Human Body Facts with No Obvious Explanation

Okay, look at yourself in the mirror.

Yeah, right in the eye. See that little fold of tissue in the inner corner of both of your eyes? Well, get ready for this. It was actually once a third eyelid or nictitating membrane. You can see it today in snakes or lizards, for example. The third eyelid was used for the same purpose as the other two, although it's unclear whether humans ever even had it fully grown. This membrane wasn't as thick as the two eyelids we have, and it could moisten the eye without obstructing the view.

Right now, all we have left of it is this tiny fold in the corner of the eye.

And most likely in the future, we will lose it altogether. And maybe we'll finally stop waking up with that yucky crust that forms in our eyes overnight. Now, while you're still in front of the mirror, look lower, lower, and lower. still. Yeah, those are your toes. Say hello and goodbye. Scientists believe that in some more or less distant future, we'll get rid of our toes completely. Our ancestors, the ancient primates, needed toes to climb trees more efficiently. They use both their hands and feet to grab tree branches. You can see it today in most monkeys and apes. They have longer and more flexible toes along with flappier feet that allow them to get a hang on branches. Their feet mobility also lets them grab objects from the ground if necessary. For us humans, even lifting a pen we dropped on the floor with our toes is a complex task, but not for our primate relatives. Humans have evolved along a different route. We started walking upright and climbed down from trees, making rigid feet and shorter toes more of a necessity over time. Today, we still use our toes for balance when rolling from the balls of our feet to the tips of the toes, but our balance is now much more centered. It first moved towards our inner feet, which resulted in our pinky toes becoming so tiny and the big toes, well, so big. As the balance moves away from the toes entirely, though, they're more likely to get fused together in the future. Now, turn around and look at your gorgeous behind.

If you've ever fallen off a skateboard or slipped on an icy patch, you must remember what a terrible thing it is to hit that tailbone on a hard surface.

Luckily for us, scientists predict it's going to go away pretty soon in the course of evolution. A tailbone is a feature that was left to us by our primate ancestors, too. And yet again, they needed their tails to achieve more mobility among tree branches, using them to fling themselves from tree to tree.

It's hard to say when humans drop the tail to never pick it back up, but facts are facts. The only thing we have reminding us of those glorious tree jumping days is the pretty useless bone at the lower end of our backs. Okay, back to the face. Now, open your mouth and say, "Ah." If you're a lucky individual to have no wisdom teeth, then you can be proud knowing that you're a product of evolution going strong. As you might know, teeth are the only part of the human body that doesn't repair itself.

So, if you lost all your teeth back in the dark times with no dentists around, the only choice you had was to eat liquid food. Not cool. Dentists believe that nature gave us wisdom teeth as a replacement for old, worn out teeth we've had since childhood. That's why they grow so late in our lives. Today though, with all the progress dentistry has gone through, we tend to keep all or most of our teeth intact until a very old age. And even if we lose some, we can always replace them with new ones.

That makes wisdom teeth a vestigial thing. And they seem to understand that since more and more people never have to go through the ordeal of teething as grown-ups.

Speaking of teeth, our entire jaw has been changing for the past oh 10,000 years and is predicted to change even more quite soon. In fact, it's been the fastest changer of all our body parts.

Back in the day, when early humans survived by hunting and gathering, they needed massive, powerful jaws and bigger teeth to chew through raw meat and grind plants. As they came to cooking and then farming, their food became less tough and so their jaws became smaller to fit the current needs. As time went by, our jaws shrank more and more, and they're likely to continue doing so in the future. With lots of processed foods that don't need much chewing, humans of the future are probably going to have more delicate facial features with thin jaw lines and smooth cheekbones.

Some body parts are not going away, but making a comeback instead. A 100 years ago, Fabella, a tiny bone in the back of the knee, was only present in around 11% of people, and scientists thought it would disappear entirely pretty soon.

But against all odds, the brave little bone has made it into the knees of a whopping 39% of modern people. It's still unknown why exactly the Fabella returned, but the most popular opinion is that we've grown taller and heavier than our ancestors. That much is true. As our diet became better and more nutritious, we learned to live longer and grow taller. We're now probably at the peak of our evolutionary height. And the fabella might have appeared in our bodies to provide a smooth surface for the tendon behind the knee to slide on, reducing friction and lowering the chances of damage because of wear and tear. Speaking of becoming bigger, let's get you back to that mirror, shall we?

Flux a little bit. Oo, nice biceps there. But unfortunately, not as nice as your ancient ancestors were. Not everything about evolution is 100% good for us. It's just a set of features that adapt at best. And that's the case with our muscles. They've grown smaller and weaker with time, especially in our upper bodies. In ancient times, humans needed big and strong muscles to do a lot of handiwork. From hunting and shleing their catch home to crafting tools and building shelters. Later, it didn't grow easier. Much the opposite.

In fact, plowing fields and building complex structures required a lot of physical strength and endurance. But as the technological progress started booming, physical capabilities gave way to brain power and machines began doing a lot of work for us. Most of it even better than us. We shifted more towards sedentary lifestyle, spending more and more time in front of computers. and our muscles have been growing steadily smaller because we simply don't need them as much anymore. It's highly likely that as the progress goes further, we'll become much slender and have more trouble gaining muscle mass. Our brain is of particular interest because it's been changing in a kind of a strange pattern. Our distant ancestors had a rather small brain at first, but the close relatives of humans, the Neanderthalss, obtained a larger brain than the average modern human has. In the course of evolution, human brain grew larger. But in the more recent centuries, it started shrinking and no one knows exactly why. Some experts say it might have to do with the change of our lifestyle and social connections. Early humans, especially hunter gatherers, had to remember every plant and animal they saw, their properties, and how to use this or that thing. They were more generalist, having to learn everything their parents knew and find out more on their own. The modern human is more specialized in a certain area, delving deeper into some narrow subject while relying on their peers for the rest. where ancient humans worked in groups in which anyone could potentially replace anyone else. We gather in teams where each member has their own specific task and is irreplaceable. Still, brain size doesn't seem to matter that much because orcas and elephants, for example, have bigger brains than us, which doesn't make them more intelligent. Happier? Hm. I'm guessing yes. And if we venture further into the unknown, meaning millennia from today, we might even develop some pretty unbelievable traits. Some go as far as to say that if the tendency for the sea levels to rise persists, humans might adapt to living in water. We might evolve to have webbed hands and feet to swim better and develop gills to be able to breathe underwater.

or if we go into space and start colonizing other planets, we will inevitably have to adapt to their conditions. Mars, for instance, has lower gravity and a much colder climate.

It will probably make humans taller and lighter, but also may cause them to grow much more body hair to keep warm. And planets with stronger gravity and higher temperatures will, on the contrary, turn humans into stocky, sturdy, and likely hairless creatures. The possibilities are endless. Hey, maybe due to social media, we'll just turn into little blobs with big eyes and thumbs and not much else. So much better for texting. H hope not. The infinite vasts of the universe hold endless possibilities and secrets.

And here's one of the intriguing questions. How life and we as humans would look like on other planets.

Imagine a world where the laws of physics, the environment, and the conditions are vastly different from what we're used to. How would we adapt and evolve to survive in these strange new lands? Let's see. Mercury is the closest planet to the sun and has a thin atmosphere. The temperatures there are extreme with the dayside reaching over 800° F and the night side dropping to -290° F. So, what can we do to survive these crazy temperatures and constant solar radiation? Maybe we can magically turn into metal. For example, titanium and platinum can perfectly tolerate high temperatures. But seriously though, there is an option. We could settle underground where the temperatures aren't so frenzied. If we lived underground, we might evolve with large eyes to better capture light. We might also evolve thicker skin to protect ourselves from the intense radiation.

Basically, we have two options. Become metal or become moles. Let's move on to Venus. This planet is extremely hostile.

First of all, Venus is known for its thick, more toxic than your ex type of atmosphere. The whole planet is covered with carbon dioxide and its surface is absolutely dry, making it incredibly hot. The average temperature is around 847° F, making it one of the hottest planets in our solar system. Also, don't forget about the crazy pressure.

Standing on Venus would be like standing 3,000 ft underwater. Only particular hearty microbes from Earth could survive in such conditions. So, if you want to live on Venus, you might have to become a microbe. But unfortunately, since we're not microbes, we have to wear special gear and equipment to survive there. Maybe we'd have to develop a heatresistant exoskeleton to protect ourselves, as well as get some new lungs that can filter out the toxic elements in the atmosphere. Let's talk about our favorite red sibling, Mars. The first noticeable change after a few hundred years would be your new skeleton. The gravity on Mars is much weaker than on Earth, so your muscles and bones would shrink. To make up for this difference, you'd have to eat more and probably start going to the gym. Also, you'd have to adapt to the low atmospheric pressure and colder temperatures. You need to retain heat, right? That means you need a thicker layer of body fat. Sorry, folks, but on Mars, we might become fatter. Another reason to start working out. Another big change would occur in your skin. Your skin is like a big barrier that protects you from harmful things such as bacteria, UV light, looking totally creepy, and so on. So, what would happen to it? Most likely, you would turn orange due to the keratenoids. Keratenoids are a type of nutrient that you get from foods such as carrots, potatoes, tomatoes, and so on.

They protect very well against ultraviolet radiation on Mars. They only have one downside. By eating a lot of pumpkins from the Martian farmers market, you'll gradually start to turn orange, but maybe it's not so bad. Maybe life on Jupiter would be easier. Yeah.

No, it has no solid land. This planet is made up of hydrogen and helium and is referred to as a gas giant. You would simply float there like in a huge cloud.

And even if you managed to land and try to walk, it would be like moving through a super thick fog. So how would we evolve there? Firstly, we might become much larger in size to withstand the immense pressures. Secondly, the temperature fluctuations on Jupiter are enormous. The surface is terrifyingly cold and the temperature rises significantly under the outer layers of the atmosphere. Thirdly, if you lived on Jupiter, there would be no verbal language. This gas giant absorbs radio waves, so even if you were speaking, no one would hear you. There would be no music either, so no parties. And what's the point then? Hey, maybe we could communicate with sign language, but that's not so simple either. Jupiter is full of wild winds and storm clouds, so it's unlikely you would be able to see anything. So, even if we evolved there in some way, our lives would still not be easy. Before landing on Saturn, you would probably want to check out its iconic rings. But you wouldn't be able to do that because Saturn's rings consist of a bunch of ice particles flying in space. So it would be extremely hard to land. So let's go straight to Saturn itself. At first, it may seem that Saturn is not bad for us. Some layers of this gas giant have quite pleasant temperatures. If we dive deeper into Saturn, it gets surprisingly warm, up to 26° F in its second layer. This is an average temperature in countries like Sweden and Canada.

But unfortunately, this is only one such layer. The rest of the planet is incredibly cold. So in order to survive on Saturn, we'd have to do a lot of work. In addition to the cold, we'd have to deal with the planet's harsh environment, including its intense storms, strong winds, and radiation. To protect ourselves from these conditions, we'd need to evolve tough skin again, find some insulation, and so on. Next planet is Uranus. Uranus has a very different environment from Earth with much colder temperatures, a lack of a solid surface, and a much different atmosphere. It's like another Jupiter, but with blue vibes. It's not that bad, though. There's even water on Uranus.

The only problem is the planet is full of ammonia, that nasty stuff we use for cleaning. So, don't be surprised if you feel the gross smell. Also, it's incredibly cold out there, almost like a neverending winter. So, what would it be like to survive in such a dark and harsh environment? We'd need thicker skin again to cope with extreme temperatures.

And again, we'd need larger eyes to see better in all this darkness. We might even have to develop a new hearing system like that of dolphins. Wouldn't that be fun? Let's move on to Neptune.

If human beings were to evolve on Neptune, they would need to adapt to its harsh conditions. Neptune, the eighth and farthest planet from our sun, is another gas giant. The only difference is this planet may have a solid core. If we were to live on Neptune, we'd need to float or swim in its methane rich atmosphere. We'd also need to develop gills or something like that in order to breathe. Basically, we turn into space reptiles or cosmic fishes. The gravity on Neptune is slightly stronger than Earth's, but strong winds make it difficult to stand in one place. To withstand the wind, we need to be much heavier. Once again, you need to eat a lot and pump up some muscles. Yeah. Yeah. Technically, it's not a planet, but we still love it and can't forget it. A small, distant, and incredibly cold world. Pluto's even smaller than our moon. And because of that, there's almost no gravity there.

It will be extremely difficult to stand on it. To avoid accidentally flying into outer space while playing football, we need to create a fake gravity machine.

And if we don't want to feel dizzy, we need to evolve a brand new nervous system. But Pluto isn't all that bad.

For example, there's liquid water under the surface and even some icy mountains.

Maybe it would be possible to survive there if we had some serious equipment, clothes, supplies, and nah, too much hassle. Anyway, from the scorching heat of Mercury to the freezing temperatures of Neptune, each planet has a unique set of environmental challenges and opportunities for evolution. While we may never truly know what humans would look like on these other worlds, it's exciting to consider the endless possibilities. Never stop looking at the stars and asking these questions. So, get this. If someone managed to uncoil all the DNA in the human body, it would stretch out to around 10 billion miles. Hey, do the math. That's twice the distance from Earth to Pluto. And that's not the only awesome thing our body is capable of.

Trillions of nerve connections are powering your memory non-stop. According to studies, after looking at 2 and a half thousand images for a mere 3 seconds, most people can recall if they have seen these pictures with 92% accuracy. Wow. Your body glows, emitting tiny amounts of barely visible light.

This glow is the product of biochemical reactions going on inside your organism.

The light waxes and wanes throughout the day, but even though it is visible, you can't detect it with the unaded eye.

From 1 to six pounds of your body weight is made up of bacteria. And from 100 million to 1 billion bacteria can live on just one tooth in your mouth. So please brush. It's impossible to taste your food without saliva. All because the chemicals in your food must be dissolved in saliva before they get detected by your taste buds. Even though it sounds like a myth, eating too many carrots can indeed turn your skin orange. Carrots have high amounts of beta carotene.

That's a compound that can cause kerateneemia. If you have too much of this compound in your bloodstream, it'll hold on to parts of your body with thicker skin. I'm talking about the soles of your feet, your knees, elbows, palms, and even certain areas around your nose. But worry not, this condition is not dangerous. You can easily reverse it by decreasing the amount of beta carotene fil food you consume.

The chin muscles, scientifically known as the mentalis muscles, look pretty quirky, giving us mixed feelings. Just look at these creepy tiny tentacles. And still, they make it possible for us to create all kinds of facial expressions that involve the lips, chin, and cheeks.

And yes, they are the culprits behind those weird wrinkles and crevices on the skin of your chinny chin chin. All because these muscles don't pull on themselves, but yank on the skin. Now, people can live without some organs, leading a normal life. The human body consists of singular organs and those that come in pairs. And speaking of the ladder, you only need one of those to survive. Your small intestine is actually not so small. It's taller than you, measuring around 23 ft. Now, the cornea, that transparent front cover on your eyes, doesn't have any blood supply. Instead, it receives oxygen directly from the air. Human beings develop their unique fingerprints very early in life while they're still embryos just 3 months after being conceived. By the way, even if fingerprints get badly damaged, they tend to grow back to their original pattern. All people are born with a diving reflex. They can get activated and shut bodily functions if one is drowning or is submerged in the water.

The human brain is by no means smooth.

But if you decided to flatten all those wrinkles covering it, the brain would be the size of a pillowcase, but not as useful. Newborn babies only blink once or twice in a minute. For comparison, a grown-up person blinks at least 10 times within the same time. Our lungs are the only organs that can float on the water.

All because they're made up of around 300 million balloonlike structures called alveoli. Also, even if we're perfectly healthy, our lungs are never completely germfree or sterile. Your nose is a superhero. It's your very own heater, filter, and humidifier. This organ is lined with tiny bone-like shells called turbine.

They contain blood vessels capable of heating the air and goblet cells that can help humidify the air. Also, the air you breathe gets filtered in your nose before going further to your lungs.

Now, every time you eat something, your esophagus, the organ your food travels through to reach the stomach, moves in a series of wavelike contractions, pushing the food forward. This is known as paristelsis. There's a bond between your digestive system and your brain. The gut brain axis. This is why stress or brain issues can affect the way your body digests food.

Now, even though hiccups are typically harmless and resolve by themselves after a couple of minutes, they aren't exactly pleasant. So, you should probably know that they might occur because of changes in temperature. The density of your brain increases throughout your whole life, all because new neural connections pop up. They appear because the structure of the brain keeps changing, too. If you don't want to sneeze, press the skin on the bridge of your nose with your fingers. When you do it, your brain receives an alarm signal. Very quickly, it puts the brake on all those other processes, including the sneezing reflex. By the way, studies have found that sneezing is your nose's way to reset. A sneeze reboots the cells that line the inside of your nose. They're called psyia. The part of your brain that's responsible for vision is in the back of your head. Interestingly, the right side of your brain controls the vision on the left side and vice versa.

If you're in some loud place, for example, in a club or at a concert, close your ears to better hear your friends, push the tragus, which is that pointy skin covered cartilage in front of the ear canal, into your ear. Then turn this ear toward your friend. On average, when a person snores, the sound doesn't get louder than 60 dB. That's as loud as a regular conversation. But sometimes the noise level can reach 80 dB. That's as loud as a working food blender. Just like salamanders regrow their tails, humans might be able to regenerate cartilage. That's the rubber-like stuff surrounding your joints. Scientists have recently discovered that cartilage could repair itself. This process is likely to be the most effective at the ankle, not that effective in the knee, and the least effective in the hip.

Now, if a person has asnosmia, which is also called smell blindness, they don't distinguish and detect smells. Your eyes never stop moving while taking in visual information.

Otherwise, you wouldn't be able to see the whole picture. These movements go unnoticed because your brain is a great video editor. It stabilizes the images and connects tons of fragments into one smooth video.

The liver is the only human organ that can regenerate completely, even if it's a mere 25% of the original liver weight.

The organ can get back to its full size. Your mouth burns when you're snacking on pineapple because while you're eating this fruit, it's eating you back. Well, kind of. Pineapple is the only known food that contains bromelain. That's an enzyme that breaks down proteins. Luckily, your stomach acid knows how to deal with the offending enzyme.

Now, we also have bacteria that can produce electricity living in our intestines. These bacteria give off electrons which creates tiny electrical currents. This might be the bacteria's way to generate energy. Deja vu might actually be something like a brain processing lag.

There's a theory claiming that it might happen when your brain is moving information from one part to another. If there's even the tiniest delay in that process, your brain will get the same information twice. In this case, it'll process it as an event that happened before. The DECT 2 gene mutation allows people to have just a few hours of sleep at night and still feel great. They don't get tired and never sleep in. On average, such people wake up at 4 or 5 a.m. No more than 5% of the world's population has this feature.

Your ears might pop or even hurt when you're on an airplane. You can solve this problem by simply chewing some gum.

This opens up your ustation tube. That's a small passage that connects your throat and your middle ear. Opening this passage helps equalize the pressure in your ears and puts an end to the popping. You can also yawn to open up the ustation tubes. Your feet are likely to become bigger with time, just like your nose and your ears. You see, when people grow older, ligaments and tendons in their feet weaken. This makes the arches flatter and the feet become wider and longer. You're out for a couple of miles with an ingrown toenail. Ouch. Now, think about those folks who tackle extreme races and marathons. To run their best, they need top-notch training and solid shoes. But there's one more thing. Perfectly trimmed toenails. And trust me, keeping those nails in check is an art in itself because there are many rules on how to do that right. To get ahead of nagging toenail issues, some athletes choose to have their toenails removed altogether, which helps them dodge problems like bruising and ingrown nails. Take Charlotte Vaserelli, an ultrarunner who had to say goodbye to both of her big toenails after relentless pain had been affecting her stride. The procedure takes about 45 minutes. A podiatrist will numb the toe, apply a tourniquet, and carefully remove the nail right down to the root. They then use carbolic acid to stop it from growing back. Recovery is pretty swift, but sometimes it can take a few tries to ensure the nail is completely gone. Now, let's say you've accidentally lost your toenail, and since you aren't a professional athlete, you decide to help it grow back. It will take you up to 1 and 12 years to fully recover. They grow three times more slowly than fingernails, only pushing around 1.6 mm a month. Plus, the older we get, the slower the process gets. With age, our toenails thicken and round out, so the growth rate slows down. It's not that everybody's feet smell bad, but if you ever notice someone's tootsies stink, here's an explanation for you. Our feet have around 250,000 sweat glands. For comparison, our armpits have 10 times fewer, only around 25,000. However, it's not the sweat that makes the feet smell. Bacteria are in charge of the stench. The primary reason is often times lack of ventilation and fungus that thrive in wet environments such as sweaty feet.

Farts and burps are just a normal part of being human. When we chow down, our small intestines don't get around to digesting all foods perfectly, and gas is a byproduct of a digestive process.

When bacteria break down leftovers in your gut, all that gas eventually has to escape, which means on average we let out about 12 to 25 farts a day. And don't worry, holding in gas won't affect you seriously. Sure, it can lead to a bit of tummy trouble, but being polite at dinner, won't mess with your health in any serious way. Gross as it is, pus actually tells you that your body is doing its job. That gooey stuff, whether it's white, yellow, green, or even brown, is just a buildup of white blood cells fighting off an infection. It means your immune system is kicking in like it should. Of course, if you see pus after major surgery, that's a flag to reach out to your doctor. But for smaller injuries, pus is just your body's way of healing, even if it's super yucky. You can even call it the white cell's precious juice, if you will. Can you give yourself a pinch without feeling anything at all? Go ahead, grab a bit of skin on your elbow and give it a good squeeze.

Surprisingly, it won't feel as bad as you'd think. That's because different spots in your skin have different kinds of nerve endings. Your elbow skin is like the superhero of skin. It's tough and has fewer pain receptors. On the flip side, the more delicate parts of your body are packed with nerve endings, making them sensitive and a bit more screamw worthy when you accidentally bump into something. You can munch on anything without actually tasting it.

All you have to do is pinch your nose and take a big bite of that not so appetizing meal. Bet it doesn't taste like much. The thing is, our taste buds only detect five flavors: sweet, sour, bitter, salty, and that savory umami.

The flavor you get from various types of meat. Still, it's not your tongue, but your sense of smell that really brings the flavor party to life. If you hold your nose, you cut off the aroma and leave your brain to rely only on those five basic tastes. That's a great life hack when you got to eat something you don't like but have to. If you're snoozing away and someone blows a puff of air at your eyes, they won't even budge. But if you're awake, your eyes are going to flutter like crazy. So next time you want to test if someone's really sleeping or not, try this little trick. You might notice that one nostril feels more stuffed up when you have a cold, but that's completely normal. It's not unusual for one nostril to be more active while the other takes a little break and they actually switch roles throughout the day. This is known as the nasal cycle. Typically, one nostril does about 75% of breathing for a couple of hours before the other one takes over. Since this cycle is controlled by your body's nervous system, you can enhance this natural pattern by consciously switching nostrils with each breath, which can help you relax. It might seem a bit goofy at first, but it could be a fun trick to get your kid to try when they need to calm down. The bones in your feet account for about 25% of all the bones in your body. There are 206 bones in total, and each foot has 26 of them.

So that's 52 bones for your two feet combined. If you do the math, that's roughly 25.24% of your total bone count.

Genetically, humans are like 99.9% the same. But not all of our genes are actually human. Out of the roughly 20,000 genes in our DNA, about 8% come from ancient viruses. Plus, another 40% is made up of repetitive sequences that scientists think might also be viral.

These viral genes have the ability to move around and replicate themselves, which could be linked to some health conditions. So, turns out you're barely half human when it comes to your genetic makeup. Believe it or not, it's rare, but some people can actually grow teeth in their ovaries. These weird growths are called terteratomomas, and they can contain all sorts of stuff like hair follicles, skin, muscle, and more.

The biggest terteratoma ever recorded was a whopping 18x 10 in and it was taken out of a 74year-old woman. Since the brain doesn't have pain receptors, doctors can do brain surgeries with patients awake and sometimes even chatting. It might sound like a scene from a horror movie, but having patients alert during the procedure actually helps surgeons avoid causing any serious harm. It's a bit unsettling to think about, though. Surprise! Your brain is the fattiest organ in your body. It's about 60% fat, and that's a good thing.

Those fatty acids are essential for optimal brain function. Imbalances could up your risk for many health issues.

Still, when it comes to having kids, your seemingly fat brain gets smaller, as if it's on a diet. Moms and dads experience shrinkage in areas tied to social cues and decision-m. These changes are totally normal and help with parenting. However, no matter if you have kids or not, your brain power still declines by the time you hit 24. Studies show that cognitive speed starts to drop and you keep losing about 15% every 15 years after. So, if you're nearly 40, don't be surprised if things take a bit longer to process. Your ring finger can give away your marital status, but it also has some interesting secrets even before you tied the knot. Back in 1998, evolutionary biologist John Manning found out that if your ring finger is longer, it might mean you had higher levels of prenatal testosterone. Since then, several studies have backed this up, showing that folks with longer ring fingers tend to excel in sports. If you've just checked your palms and your fingers are really long, don't be too fast to judge.

Not all scientists agree with that.

However, there's some proof that men with longer ring fingers can be a bit angrier than other people. Maybe that's why boxing gloves resemble mittens to keep you guessing about who the real champ is. You know, when you have a stuffy nose and all you can think about are the nights you've taken smooth breathing for granted, our bodies do a lot of work to keep us comfortable every day. So, in the spirit of staying grateful, let's take a look at a couple of these amazing things the human body does every minute. Starting with our eyes, which are constantly relaying loads of visual info to the brain. The cornea acts like an entrance gate, skillfully bending light. The iris, or the colorful part, adjusts the light dose, and the lens focuses the rest onto the retina. This last one then transforms all that light into electrical signals that are sent to the brain for interpretation. Sounds like a lot of work, but it all gets done in milliseconds. This means that in just a single minute, our brain handles somewhere around 600 million bits of visual data. More than half our bodies are made of water. 55% if you're a lady and 65% if you're a gentleman to be precise. To make sure this water balance is always in check, our bodies come equipped with a hydration monitor. It's always looking into how much water we're losing through things like sweating or even breathing.

If as little as 1% of the water quantity goes missing, we'll start to feel thirsty. We also wouldn't be here if it weren't for those hearts pumping in our chests. Well, actually, just one heart per person. The speed at which it pumps can change depending on how fit you are, your feelings, your size, and even if you're doing a new yoga pose that requires a bit more effort. On average, doctors say adults have anywhere between 60 to 100 heartbeats per minute when they're resting. Now, the fitter you get, the less pressure you put on your heart, and you might even end up having a heart rate as low as 40 beats per minute. Each time this organ gets a little thump, it's pushing about 2.4 o of blood around your body. If your resting heart rate is 80 beats per minute, your heart's pushing 1.5 gallons of blood every 60 seconds.

Ever wonder how fast your body bounces back after losing blood? We've got on average about 10 pints of it in our adult bodies. When one of them is lost, our bodies start working hard to replace it. And it's faster than you'd imagine.

Within 24 hours, the volume loss is replaced. And within a few weeks, we're as good as new. That's because every second, our bodies make some 2 million fresh red blood cells. That's 120 million every minute. When it comes to white blood cells and platelets, the process is even faster. Our breathing mechanism is fascinating, too. For grown-ups, the regular breath count is about 12 to 20 breaths per minute.

Infants, however, have a faster rate of 30 to 60 breaths per minute. When you take in air, it requires the effort of an entire team. Your brain's command center send signals down to your diaphragm, telling it to flatten out.

Your ribs and abdominal muscles adjust to allow your chest to expand, pulling the air into your lungs. Breathing out is a bit easier. Your used up air gets pushed out by your elastic lungs. But when you're putting in a bit more effort, that's when your abs help a bit more in the exhale process.

Now, when it comes to reading, our brains can amp up that skill, sometimes reaching up to a thousand words per minute. If you do the math, it means your brain can read a 300page book in just 2 and 1/2 hours. One interesting feature about how our brain processes reading is that it doesn't necessarily do it in a straight line. In fact, our eyes do these unique movements called sacads. They're quick jumps across the text back and forth. Sometimes it's a big leap, other times a tiny hop. They help us soak in tons of information fast and they happen a bunch of times every second. How big or small the jump is depends on how good we are at reading and how familiar we are with the topic at hand. Do you want to find out more about a variety of topics like science, pop culture, or history? Well, be sure to hit that subscribe button so you can stay uptodate with our latest videos. Our skin is the largest organ we own and is perpetually shedding around 30,000 cells every 60 seconds. Most of the time, we don't even notice, but our faces and bodies are constantly removing layers. Yep, a lot of that dust around your house is you. It's a month-long journey for those fresh skin cells to pop up to the surface, and that process speeds up or slows down with age. During our 60s or even later, it can take up to eight weeks for cell turnover. And that buildup of skin makes your complexions look a bit dull. Thankfully, there are a lot of products we can use these days to help with dry skin, like moisturizers and serums. You can't talk without your tongue. Well, you can technically, but most people won't understand a word you're saying. On any day, our tongue teams up with our lips and teeth to turn throat sounds into words that make sense. The tongue itself is flexible and speedy, capable of letting out more than 90 words a minute using a variety of over 20 moves. While we can vocalize without using the tongue, we need it to pronounce consonants like T, D, L, and R, or if you're a pirate, R. This important organ is the same reason parrots can so easily imitate us. Though most of them have no idea what they're saying. These birds have a thick tongue, and even though they've got fewer muscle moves, it helps them mimic human speech quite accurately. So, be careful what you say around them. Humans also blink 15 to 20 times each minute. It might not sound like a lot, but it does mean we're spending about 10% of our awake time with our eyes shut. For many years, scientists believe that blinking served a single purpose, to keep our eyes moist. That's mostly why we produce tears, by the way.

And with the help of our eyelids, this creates a little cover for the whole eyeball, preventing it from feeling itchy. However, blinking does more. A study from the past decade pointed out that when we blink, our brain hits a mini reset button. It powers down some parts linked to vision and attention.

And since attention messes with how we perceive time, blinks could be like these time travel moments for our brains or many power navs, if you like. Now, on average, people have around 35 to 48 thoughts per minute. It depends on a variety of things like what we've been through, how we're feeling, and even where we are. When it comes to thought formation, we do know that brain cells can communicate. But understanding exactly how our ideas pop up in our minds is still a bit of a mystery. Our brain features many neurons, these fascinating cells shooting out electrical charges to talk to each other. It's these neurons that spill out brain chemicals called neurotransmitters.

Think of it as passing notes that create electric signals. And as these signals surf through thousands of neurons like a wave, thoughts pop up in our heads. Now, each time you munch on a snack, you're fueling up this power plant, which is your body. One single calorie from your food is around 4,200 energy units called jewels. If you're eating 2,000 calories a day, you're transforming that into almost 6,000 jewels every minute. And here's how everything happens. After you eat, the food follows its journey through your mouth down into your stomach and makes its way into small pieces in your bloodstream. Imagine tiny delivery trucks carrying oxygen and other useful substances to your cells. Once inside, these cells have many factories inside called mitochondria. They're responsible for turning those deliveries into adenosine triphosphate or ATP. This is our cell's energy currency. It's used to make more cells. It helps us move or even send messages through electrical impulses to other cells. Come to think of it, this sure makes me want to be nicer to my body for all it does. How about you?

You wake up one morning and while you're brushing your teeth, you notice a lump on the inside of your mouth under your tongue. Immediately, you're concerned.

You've never noticed this before. But not to worry, it's just Taurus mandibularis, a simple bony growth on the mandible of your mouth. If you have this extra bit of bone, you are part of the 40% of people with this anomaly.

Although it can be more common depending on where you're from. For example, in the USA, this only occurs in 10% of the population. Bones are significant pieces within our bodies. We have 206 of them altogether. But some people may have an extra bone that they weren't expecting.

We all have 12 pairs of ribs, equaling to 24 in total. However, 0.5% of people may have 25. The 25th is known as a cervical rib.

Present from birth. It grows from the base of the neck just above the collar bone. It can be on either side as a fully formed rib or just a thin strand of tissue fibers. There are some parts of our body that have remained with us throughout our evolution as a species. And some of us no longer share that same physical trait. The palmis longus is a small tendon located in your wrist. By pressing the pads of your fourth finger and thumb, then clenching your wrist, the inside of your wrist will show the palmus longest popping out. If this isn't visible, then you are part of a relatively small percentage that no longer possesses it. Lacking it has no effects on the strength of your grip, but being absent does give a decreased pinch strength in the fourth and fifth [Music] finger. It's believed that this muscle was actively used sometime in the evolutionary process of our species. It hasn't affected our bodies in any way, and it's merely a trait that some of us continue to have. It's also not dependent on either hand, regardless of which hand is dominant. Which hand do you use more often? If you're left-handed, you're part of the 10% club. And if you're ambidextrous, you're within the 1% to use both of your hands dominantly. Most ambidextrous people initially only use their left hand. Ambidexterity and left-handedness share the indication that they are using both sides of the brain. Right-handed people are generally dominant only to the left side of the brain.

[Music] We all have tailbones, a reminder of our long story of evolution. We stopped using our tails around 25 million years ago. Although, while we are still growing as embryos, we go through the process of growing a tail. And after about 8 weeks, we lose it [Music] completely. There are some cases of humans being born with a tail. There are about 25 confirmed cases known to scientists.

Those born with tails though won't have any real benefit other than what the tailbone does for balance anyway. The tails have no function other than physically being there as they have no bones. The tails only consist of nerves, vessels, and muscles. Do you find that you are a picky eater? Do you think that coriander tastes like soap or you can't stand pineapple on pizza? This may be due to what kind of taster you are. Up to 30% of people are considered super tasters and will experience different levels of enjoyment or disappointment from their foods. Food that is bitter to the super taster will likely be sweet to average tasters who make up 40% of people. There are also 30% of people who are non-tasters and won't find anything too exciting.

Do you have the ability to identify musical notes? About 1 in 10,000 people can flawlessly distinguish perfect pitch naturally. Although this doesn't necessarily mean that they will be the next big pop star. They're just able to easily identify a specific musical note upon listening to it. Our eye colors are so diverse. The difference in light exposure to eyes throughout the world determines how much melanin is produced, which helps create many different shades of color. Since migration has become more common over the past 100 years, the variations of shades of color are numerous. Your genes, of course, also playing a huge part.

We could list hundreds of different shades of eye color to show how many variations there are, but we'll limit the distinct categories down to six main color groups to keep this brief. The vast majority of people have brown eyes. About 79% of the world's population share this eye color. Once all humans only had the brown pigmentation until around 6 to 10,000 years ago when humans migrated to Northern Europe, a mutation occurred helping the eyes to adapt to the change of light. Blue eyes became the most common of the mutated coloration and all of them today can be traced back to one ancestor from Europe. Today, blue eyes make up around 10% of the human population. Amber and hazel eyes each take up 5% respectively. Gray eyes are up to 3% and the rarest of eye colors are green ones consisting of only 2%. Rarer still is heterocchromia iridom where both eyes are of different colors.

It's inherited and also affected by other genetic factors. Only 1% of the human population have this incredibly rare attribute.

Although blue eyes have become more common, they're only more prominent within areas where people contribute similar variants of genes since blue eyes are a recessive trait, just like red hair, which only occurs within up to 2% of the population. If you have red hair and blue eyes, you will be part of the smallest percentile for hair and eye variety that makes up only 0.17% of the human population. Although green, gray, and hazel eyes are less abundant than blue, their genes are more dominant. So within the small pool of red heads, blue eyes are less likely to occur. The melanin that has helped mutate eye colors can also have other effects on the human body. A genetic mutation that affects the melanin occurs in 0.005% of people in the USA, creating albinism.

The occurrence differs in many ways throughout the world. The same as the effects with eyes. In albinism, the pigment production is altered to distribute major cells that affect the coloring of the skin, the hair, and the [Music] eyes. Most people with albinism will have snow white skin, snow white hair, and their eyes are a pale blue pinkish color, the pupil itself being red. The redness comes from the light reflecting off the vessels in the retina. There is another form of albinism which has a smaller amount of pigmentation and the shade of skin and hair are slightly darker. Albinism occurs not only in humans but practically all mammals, reptiles and amphibians. Do you have a small hole at the front of your ear above the ear canal? This is the preuricular pit.

During the first six weeks of a child's development, long before being born, the oracle, which is the external part of your ear, will develop. The pre-uricular pit forms when the oracle doesn't fully fuse. This occurs within less than 1% of humans.

Although there's speculation that having this little hole is the remnant of gills that we once had from our seafaring ancestors, there's nothing solid to confirm this theory.

There are some unique things we have that give us an advantage in everyday life. Some people carry a gene mutation of the DEEC2 gene, also known in proper English as familial natural short sleepers. Essentially, it means people within this 1% only require about 6 hours of sleep each day.

Most people will probably feel burned out after a day of this, but those lucky enough to be within this 1% will be sure to make the most out of their day. Have you ever looked at a picture and noticed that the color of something was different to what someone else can see? It may be that you have a rare ability to see more colors than everyone else, possibly seeing 100 million different kinds of shades.

If you do, you're part of the rare group of people called tetrachromats who have four cone cells in their eyes, unlike everyone else who has three and are identified as a tri chromat. Studies are varied on who is part of this rare ocular phenomenon, though it's more prominent in females.

It suggested that up to 15% of women have this rare capability. Incredibly, it's an ability also shared with some species of birds, insects, fish, and other mammals. You know, these before and after makeovers, well, if you saw a pic of an average human who lived about 1 million years ago, compare it to a pick of an average human who lives today, you'd be astonished. And get this, it's a makeover performed by mother nature.

Like back in the day, the earliest human species were basically tiny with long arms and short legs. They needed a big digestive tract to handle all those plants they were chowing down on. And their rib cages were super wide to make room for all the organs breaking down their food. Time went by and some of these humans started adapting to hot climates and they all got narrow and leggy to stay cool. They started eating meat and other quick to digest foods, which meant they could have smaller digestive tracts and use more energy for their tall bodies and big brains. And when humans spread to colder climates, they evolved short, wide bodies to conserve heat, but they still love their raw meat and cooked food, which could be easily processed in a short digestive tract.

Check out this skeleton of an 8 to 9year-old Homo erectus kid from East Africa. He was already 5' 3 in tall and weighed 106 lb. If he had grown up, he could have been almost 6 feet tall. His lean body was perfect for hot, dry environments. And then there were the Neanderthalss, who were only about 5'4 in tall on average. They had short, broad bodies that were great for dealing with winter cold and even ice ages. Junk food is bad for our teeth.

But did you know that it can also cause dental crowding? Back in the day, our ancestors had straight teeth with wisdom teeth. But thanks to processed diets and milling technologies, our jaws have shrunk and our teeth are now vying for limited space. So if you want to avoid a mouthful of crooked teeth, stick to a less processed diet. As humans spread out and adapted to different environments, they changed their body shapes to survive. And as diets changed, so did bodies. But one thing's for sure, early humans were super active with thicker and stronger bones than we have today. Nowadays, we're evolving sleeker and weaker bones thanks to our less physically demanding lifestyles. Yeah, it's cool to see how much we changed over time. Humans were cool back in the day, but they're probably even cooler now. You may not know it, but your bones are like super models. They're designed to be used all the time, and they look pretty good, too. But guess what's even stronger?

Your teeth. When you bite down, your teeth can exert a whopping 5,600 lb of pressure per square in.

That's some serious chomping power.

Speaking of bones, did you know that they're made up of water? Yep. About 25% of your bone mass is actually H2O. And here's another fun fact. Your eyes are like car engines. They need fluids to function properly, just like an engine needs gasoline. So, when you've blinked up to 20,000 times a day, you're basically giving your eyes a windshield wash. Have you ever blushed and felt your cheeks turn red? Well, did you know that your stomach lining can blush, too?

When you blush, there's an increased blood flow in your body, and that includes your stomach lining. It turns red because it has plenty of blood vessels. And when there's more blood than usual, it shows. Now, we all know that plastic is bad for the environment. But did you know that we can actually digest it in tiny quantities? However, our digestive system can't handle grass. Grazing animals have special teeth and several stomachs to process raw leaves and grass while we're stuck with just one stomach. We all have two super fast muscles that control our eyelids closing. They're actually the fastest muscles in our body and they shut our eyes within a mere.1 second when triggered. And while we still don't know why we blink, we do know that women blink more often than men and that we tend to blink in unison when watching a movie with friends. Maybe it's just a weird human thing. You flex that strong handshake and think it's all because of your gym grind. Ha! Turns out your pinky finger is the real MVP. No joke. Believe it or not, that little finger packs a punch and is responsible for 50% of your hand strength. Who knew the underdog could be such a powerhouse? Your toes are like two little homies that carry almost half of your body weight and don't even listen to people who say you don't need them.

Your toes are the most important guys when it comes to walking and pushing you forward. Our hair color is easily explained by jeans. There are not more than 2% of people with natural red hair.

They're followed by blondes about 3% and by all the varieties of brown shades only about 11%. The vast majority goes to black hair including very dark brown. Who knew that nails had a secret talent besides helping us pick up tiny objects and peel off stickers. They also give us a structure to press against so we know how firmly to hold anything.

Talk about multi-talented. Move over, Rapunzel. It's not just our hair and nails that can grow. Our liver can regenerate itself from just 51% of its original size back to full size. But don't go damaging it too much or you'll end up with scars. Did you know that the skin is the largest organ in our body? It makes up a whopping 15% of our total body weight.

And if you shed more than your fluffy cat snowball, don't worry. It's normal.

We lose up to 9 lbs of skin cells every year. Gross, but fascinating. Who would have thought that tomatoes have more genes than humans?

But don't worry, it's not the number of genes that matters. It's how they all work together. So, go ahead and enjoy that tomato sauce on your pizza. Hold your nose the next time you eat and see how much your taste buds fade. It turns out that the nose is actually responsible for 75 to 95% of our taste perception. So, don't underestimate the power of those sniffers. Keep your mouth hydrated or your taste buds won't work properly.

Saliva triggers chemical reactions with enzymes that break down the food as soon as it enters your mouth. So, drink up and savor those flavors. Forget about distinguishing between 10,000 smells. Recent research shows that we can actually differentiate between over a trillion smells. And not only that, but smells can evoke some distant memories, too. So, next time you catch a whiff of something familiar, take a moment to reminisce. When you're snoozing away, your sense of smell goes on vacation, too. So, even if your room smells like a dumpster fire, you won't even notice it.

Sweet dreams, right?

And speaking of dreams, did you ever wonder why some of them are in black and white while others are like a rainbow explosion? Well, apparently it all depends on the TV you watched as a kid.

So, I guess your grandparents had some pretty boring dreams, huh? Now, let's talk about listening to your heart. Not only is it a great metaphor for following your dreams, but it can also give you away if you're lying. Yeah, your heart rate starts racing like Usain Bolt when you're fibbing. Okay, brace yourself for this one. Even if you brush your teeth like a champ and use mouthwash like it's going out of style, your mouth is still a germ hot spot. Gross, right? But don't worry, most of those bacteria are actually good for us and keep the bad stuff away. But wait, there's more. The belly button is actually the second dirtiest place on our bodies. Yeah, I know. Who knew?

Since we don't really use it after we're born, it becomes a breeding ground for all kinds of icky stuff. It's got over 2,300 bacterial species living in there.

So maybe it's time to give our belly buttons some extra TLC. Paral eye or third eye, one of the features we lost almost 250 million years ago. If you take a closer look at animals like frogs or lizards, there's a random dot somewhere between their eyes.

It's not just a random dot, but an actual organ. Scientists claim it's some kind of sensor that detects daylight.

Not just that, it produces melatonin, a special hormone that regulates our biological cycles, such as body temperature, reproduction, and sleep.

They noticed this eye gradually became smaller over time, which means evolution realized it's a feature animals don't actually need. Maybe it happened because cells in our normal eyes became efficient enough so we didn't need one more eye to sense or when we should sleep. Also, more and more animals were becoming warm-blooded with time, which means they were able to regulate their body temperature better. We have part of the organ even today, but in the form of the pineal gland in our brains, still in charge for melatonin. Either way, bye-bye third eye. There's a gene called gula. With it, our ancestors could produce their own vitamin C. Not in a way they could set up a stand and sell it, but enough for the body to use it.

Around 60 million years ago, the gene kind of stopped working. Not randomly.

Our ancestors probably started getting enough of the vitamin C with the fruit they ate. Some of our very, very distant primate cousins that took a whole new direction in a family tree, such as lemurs, can still produce their own vitamin C. At some point, evolution decided they needed it while we didn't.

It's not just us. Our side of the primate family tree also doesn't need it anymore. Monkeys, apes, tarscers.

Bye-bye, goulop, too. We have lemons and oranges now. Our body would lose lots of energy if it had to deal with all those traits our ancestors used to have. So, it kind of deactivates those we don't need anymore. Let's say electro reception. It's the ability many amphibians and fish have. For example, the electric eel uses this feature to detect prey when water is murky, communicate, or as a navigation system.

Humans and our land cousins lost this feature because electric current can't flow through the air that easily. Then there's this thing called Jacobson's organ. It's found inside the nose and has a purpose to sense pherommones and odors. A snake flicks its tongue. Cats and horses make those weird faces. They all use Jacobson's organ. We also have it, but it doesn't quite seem to work.

It doesn't send or receive signals from our brain. And scientists think we lost the ability to use it over 20 million years ago. As human habits and the way of life changed over time, we needed bigger brains. Scientists have skull remains of our ancestors from different periods. So, they've realized our brain got way bigger over the last 3 million years. We needed to think of ways to deal with climate changes, big predators chasing us, finding some new nice food.

Yep, the brain grew for a reason. Food had a huge impact on our evolution. For instance, animals that only eat meat lost their sweet taste receptors because, well, they gave up on dessert, so didn't need those kinds of genes.

Humans are omnivores, so we've always had a well-rounded set of receptors that could recognize taste pretty good. These taste receptors came in handy because they could tell our ancestors which foods were good for them and which ones were toxic. Some bitter taste receptors stopped working through time since humans have changed their eating habits.

For instance, we learned to use fire for cooking, so many plants were less toxic for our bodies. We became sophisticated when it came to preparing food and also learned how to share information we discovered by communicating and using language like in cookbooks. We didn't need all the taste receptors anymore.

So, our body decided to shut them down and leave those that would come in handy in the future of our species. Luckily, we didn't lose our sense for nice chocolate. Our jaws have also changed.

Our ancestral relatives had way bigger jaws. But since we started eating softer and cooked foods, as well as using our brains more, the structure of our head needed some changes. Teeth became smaller, too. Plus, we lost some. Many people never developed third mers. We also call wisdom teeth. They grow between the ages of 18 and 25. We can do without them, but for our ancestors, they were pretty much vital. By this age, their teeth had already become worn out, so third mers were possibly a replacement they needed. We may wonder why exactly we have body and head hair.

But scientists wonder why we don't have more of it. Hair on our scalps is long, a bit shorter in some areas, and we don't have hair on the unders sides of the wrists, palms, and the soles of our feet. One of the popular theories about human ancestors says that when moving from cool, shady forest to the hot, dry savannah, they got a new way of regulating their body temperature. They lost the fur along the way, which made it easier for them to catch their prey without overheating. Later, they discovered clothes and fire, which could keep them cozy during the cold times. Of course, there are more reasons for losing fur. Some say without fur, there's less chance of face lice or other parasites. Other researchers think that during dry seasons, humans would try to catch prey near lakes in shallow waters. Hair is not such a good insulator in water. So, humans lost fur and instead got a layer of fat. Now, 85% of people can't wiggle their ears.

There's a muscle that surrounds our outer ear, and scientists believe it used to allow our primate ancestors to move their ears in whichever direction they wanted. That helped them determine where the sound was coming from. After they started living in groups, they didn't have to completely rely on themselves. So, they lost that feature.

Apes can use their feet as well as they can use their hands thanks to the planter muscle in their feet. With that muscle, animals can grip and do anything they want with objects they're holding.

We also have this muscle, but it's underdeveloped and rather useless. 9% of humans are even born without it now.

Hiccups are also one of the evolutionary leftovers humans may have gotten from their water dwelling ancestors. Fish push water through gills while amphibians gulp air. That's something mammals don't have wired into their brains. So, this reflex can cause spasms of our diaphragm, which in the end leads to hiccups. When we're angry, our lips may twitch. That's also a feature that used to be important for our species.

When they wanted to scare away predators or potential danger, they would bear their teeth the same as bears, wolves, and chimps do. Lip twitching is the first step towards it. Many people want to climb to a higher position or sense the urge to lift their feet when feeling anxious or scared. Evolutionary biologists believe it's because so many early land mammals used to climb trees when they felt a threat coming.

Goosebumps are something that we do have, but compared to old times, they're useless now. When hairy creatures felt cold, a reflex would contract those small muscles that make the base of hair follicles. That way, the coat was standing up and trapping more air so they felt warm. Today, it's just a reminder you need a jacket and that nice feeling you get when hearing your favorite song on the radio. All living creatures can trace their ancestry to a single bacterium from billions of years ago. DNA is that special thing that holds all the information our cells need to know. We all start as one cell that then grows into trillions of them until our body is formed. DNA completely controls our growth, eye color, height, and so many other traits. It's not just humans. Even snakes have hipbones that say they used to have four legs, just like their dear cousins, lizards.

Dolphins and whales have some kind of small bones in their bodies that show they used to have hind legs. Yep. Fossil remains say these marine mammals were once four-legged and walked on land. To be precise, about 50 million years ago.

Evolution doesn't actually track a straight line from species to species.

It's more like a huge tree with plenty of branches where some lead to new ones.

A trait there, a trait then, some in, some out, and bam, some completely new species are there. For example, birds.

Who would have thought they evolved from dinosaurs? They even lost their teeth along the way. And yeah, both seem to be coming from reptiles. Oh, and those nuts over there, that's part of my family tree. So, check this out. There are people who can bend down their pinky without bending the ring finger, but most find it hard or even impossible to do. When they move their middle or little finger, they tend to slightly bend their ring finger, too. Yep, me too. Globe luxation is an extremely rare condition when people can make their eyes protrude out of their sockets.

Unfortunately, this ability comes with downsides. It can cause numerous eye issues. Some indigenous groups of people like Tibetans can survive at altitudes as high as Mount Everest. This rare ability most likely appeared after years of evolution. The ancestors of modern Tibetans lived in high regions for thousands of years and developed red blood cell adaptations, making it possible to survive with dangerously low levels of oxygen. The Baju are sea nomads living in Southeast Asia. These people have evolved an extra-l large spleen serving as a repository of oxygenrich blood cells. Thanks to that, they can easily spend 5 to 10 minutes fishing underwater without coming up for air even once. Now about 14% of the population don't have a palmis longus muscle. Oh, it's actually a rudimentary part of the body and the need for it disappeared in the process of evolution.

So if you don't have this muscle, worry not. Its absence doesn't affect the work of your forearm anyway. About 5 to 37% of people don't have wisdom teeth from birth. These teeth are not really needed anymore. They were important for our ancestors since they helped to chew hard food like nuts, roots, and meat and saltwater taffy. Nah, I made that up.

But since most of the food we eat today is processed, wisdom teeth are now a mere addivism. Most people have just one clockwise hair whirl. But five out of 100 people have a double crown. And if both whs are directed counterclockwise, this makes a person even more unique.

Some scientists think there's a genetic link between hair world direction and handedness. A bit more than 8% of right-handed people have counterclockwise hair whs, but in the left-handed, this number grows up to 45%. A man's brain gets older faster than a woman's. As men age, they start complaining about memory problems and lack of concentration more and more often. At the same time, women don't have such acute problems with memory, but they feel depressed more often. H, which one would you choose? Now, when someone is lying, their own nose gives them away. Psychologists from the University of Granada have discovered that when a person tells a lie, the temperature around their nose and in the inner corners of their eyes goes up.

This phenomenon got the name of, wait for it, the Pinocchio effect.

Japanese people have particular bacteria in their intestines. These bacteria help them to digest sushi. The Japanese have been eating raw seaweed for centuries.

Microorganisms dwelling on the surface of the seaweed got into their bodies and actively developed. Nowadays, the bacteria help Japanese people digest raw food and prevent different problems connected with food. So, people have as many hairs on their bodies as chimpanzees. The hair count of a person and a chimp is approximately the same. The only difference is that human body hair is mostly useless and so fine that it's almost impossible to see. Humans don't have more genes than other species. In fact, people have fewer genes than a worm. Tomatoes also have many more genes than you do. But we are such complicated creatures. Well, recently scientists have concluded that the number of genes that a genome contains isn't closely connected with the complexity of a living being. Let's take a breather. Speaking of which, your left lung consists of two loes, while your right lung is divided into three parts. Plus, the lung on the left is a bit smaller since it has to make room for your heart. Your lungs also contain around 1,500 m of airways. It's more than half the distance between New York and Los Angeles. There are also more than 300 million alvoli, which are tiny balloon-shaped air sacks in your lungs. People have five most obvious senses: vision, smell, touch, hearing, and taste. But that's not all. How about thermosception, the sense of heat, or nonsion, the perception of pain, or your body awareness, propriioception? To figure out what it is, close your eyes and touch your nose. Got it? That's propriioception in action. This list can be much longer. Some experts state people have from 21 to 53 senses. So, your fingers get all wrinkly after you spend too much time in the water. Pruny fingers are caused by the narrowing of your blood vessels. When you stay in the water for a long time, your nervous system makes your blood vessels shrink. Your body sends the blood away from that area, and this loss of blood makes your vessels thinner. The skin starts folding over them, forming those funny wrinkles. Scientists think this process helps us have a better grip when our hands and feet are wet. There are three kinds of cone cells in the average person's eyes. These cones help to recognize the colors in the blue, red, and green spectrums. Thanks to them, most people can distinguish around 1 million different shades. But those with tetrachromacy have four cones in their eyes. This feature allows them to see up to 100 million different hues.

This vision anomaly is extremely rare and is much more common in women than in men. Interestingly, most people with tetrachromacy don't even realize they see the world brighter than others. Now, not all people have round pupils. Two people out of every 10,000 have unusually shaped pupils. Most commonly, they resemble keyholes. This eye disorder is called coloba.

Interestingly, some people with this condition don't have any problems with their vision. Only 3 to 22% of people in the world have Morton's toe. It's a foot structure where the second toe is longer than the first one. Michelangelo's David and the Statue of Liberty both have this unusual body feature. Hey, toes up. In some people, saliva accumulates in a gland under their tongue. It can then get propelled out in a stream when a person presses on this gland. If the mouth is open at the moment, a jet can reach several feet. This process called gleeking can occur spontaneously. A person accidentally pushes their tongue against the gland while eating, yawning, talking or cleaning their teeth and voila. Up to 35% of people can bleak, but just 1% can do it on command. I had a friend in college who did that. Yeah, it was weird. About 18 to 35% of people have an interesting reaction to sunlight. They sneeze. This phenomenon has its own name, the Fodic sneeze reflex. In the Greek language, it's called sunsne. Just like salamanders regrow their tails, humans might be able to regenerate cartilage. That's the rubber-like stuff around your joints.

Recently, scientists have discovered that cartilage might be able to repair itself. Most effectively at the ankle, not that well in the knee, and least effectively in the hip.

The human brain is 73% water just like your heart. That's why if your brain loses even 2% of liquid, you start feeling exhausted. This also makes your memory get worse, shortens your attention span, and puts a damper on your mood. So, drink up. Your brain is constantly processing tons of visual information around 600 million bits per minute. It all starts when the light goes through the cornea, your eyes clear, protective outer layer. Then the light turns into electrical signals.

They travel to your brain and it interprets them into the images you see.

It takes milliseconds for this complicated process to happen. People who live to be 110 years and older called super centinarians may have a secret. Researchers have discovered that their immune cells called te-helpers might change and adapt to the late stages of aging. These cells are likely to protect them from viruses and other health problems.

We've become impressive multitaskers thank or rather it only seems so. The human brain can't concentrate on two things at once. What it can do is to switch between several tasks really fast. But it makes your attention span shorter and harms your short-term memory and the ability to learn. So put that phone down. Ready for a shock? Only about 43% of you is actually you. The rest are your friendly neighbors, microscopic creatures that help you function properly. They mainly live in your gut, but also spread to other parts of your body and never leave it. Still, even though your own cells are fewer than microbial ones, there are on average about 100 trillion of them in you. If you take all the microbes dwelling within your body and count their genes, it'll be anywhere from 2 to 20 million genes and their combinations. Tomatoes have more genes than humans. Well, the part that's actually us, of course. This shouldn't concern you, though, because it's not the number of genes that matters, but the complexity of their connections. Our brain is actually pretty large, almost as large as a pillowcase. It's squeezed into a relatively small head just because it's very wrinkly. If you could spread it out, you'd see how brainy you are in reality. When you age, your brain is gradually reducing in size. By age 75, it's much smaller than at 30 and it starts shrinking by the age of 40. It happens in everyone and doesn't affect your mental strength in any way. Our brain can store only seven bits in its short-term memory. Don't even try to compare your brain with a phone capacity. Not even the one you had back in 2005. A mere bite is eight bits.

That's why you can't even learn a phone number by heart. Our short-term memory functions just like a chalkboard. You can get some info, but sooner or later you run out of space. Working memory is an essential thing that we need to perform almost any everyday activity, including basic conversations, navigating in the city, and even trying to copy the moves from a workout video.

Our strongest and most emotional memories are usually fake. It's the way the central memory works. It gives us the confidence to believe everything we remember is real, even though we should be confident about fewer details. Your bones become more brittle with age as well, and your spine gets compressed.

That's why older people often lose some of their height. In the same way, you're a bit taller in the morning than in the evening because your spinal column gets some rest while you're asleep. This effect is temporary, but the one that comes with age is unfortunately permanent. Our lifespan is programmed within our cells. They constantly renew and divide, but they have a sort of internal timer that stops at some point.

Some cells also stop reproducing sooner than others. On average, cells cease dividing when we reach the age of 100.

That means if we could find a way to trick ourselves into turning off the timer, we could potentially live forever. Among mammals, only humans can always walk on two hind limbs and keep that posture for their entire lives. You might object that kangaroos and gorillas move in the same way. But kangaroos use their tail as a third leg, and gorillas use the help of their long arms to keep balance. Body fat isn't just a nuisance.

It acts as insulation material, energy reserve, and shock absorber. Your body sends the most fat into your waist region because that's where your internal organs are. If something happens to you, this layer of fat might as well protect your vitals from irreparable damage. Your bones take part in metabolism, too. since they mostly consist of calcium. When there's not enough of this element in your blood, bones start shedding it into the bloodstream, balancing your body. And vice versa, when there's too much calcium in your blood, it goes into the bones to be stored for later. Your skull consists of 28 different bones, many of which are fused together to protect your brain. The mandible or lower jaw is the only skull bone that's only kept attached to your head with connective tissues and muscles. And the smallest bone in your whole body is inside your ear. It's called stapes and it's no larger than a grain of rice. The only bone to have a sense of humor in your body is inside your upper arm. That's why it's called humorous. Okay, I made that one up. Move along.

Some of the strongest muscles in your body aren't in your arms or legs.

They're in your head. Massi is the main muscle responsible for chewing, and it needs to be the strongest for you to eat normally. And you know those muscles that allow you to move your ears? Those are temporales, located above your temples. They also help you to chew your food. We've got two really fast muscles.

They control the eyelid closing. In fact, they're the fastest muscles in our body. Eyes are fragile and need protection. That's why when a reflex is triggered, these muscles shut the eyes within less than a tenth of a second.

It's been believed for a long time that a person could distinguish more than 10,000 smells. A recent research showed that people were able to distinguish more than a trillion smells. We also remember them better than anything else.

And smells can even evoke some distant memories. We recognize only purple, blue, green, yellow, and yellow, red colors. Everything else is a combination of these three. It's impossible to calculate how many of these combinations the human eye sees because every single person has slight vision differences, but it's about 1 million combinations on average. We feel about 80% of the taste of any food thanks to the nose and its ability to recognize odors. If you hold your nose while eating, you will taste almost nothing. You might have a chocolate bar or smoked fish in your mouth. There will be no difference for you. Your sense of smell turns completely off while you're asleep. Your brain just doesn't register any smells.

So, if you fallen asleep and then something starts stinking in your house, you won't be bothered in the least.

Rover, you bad boy. Your nose doesn't just help you breathe and catch odors.

It filters the air for sensitive throats and lungs. If we inhale dry air, the nose moistens it, cools it, and heats it if it's necessary. Also, the nose cleans the air from dirt. We can accidentally digest small objects such as plastic items, glass, coins, and many other small objects. They'll make their way through the digestive tract within 48 hours. And there's even a man who managed to eat a whole airplane. It took him years, though. But little by little, he finished his metal meal with no trouble at all. When asked if the plane was staying there forever, the guy replied, "No, just passing through." Yeah, I made that up. Speaking of meals, you feel sleepy after a hearty lunch or dinner because of your basic instincts.

Your brain thinks, and rightfully so, that when you eat, you're safe. And if you're safe, you can lie down and have some rest before going back to the world so full of dangers. Every person has their unique smell that can't be confused with anyone else's. Still, if you have an identical twin, you will both have the same smell. Now, our brain perceives giving presence as a more positive act than receiving them. Humans are social creatures. That's why when we do something good for others, we feel good ourselves. The brain gives us a reward for acting this way in the form of oxytocin, the happiness hormone. Our eyes are powerful tools, much more so than any camera invented to this day.

But still, unfortunately, they can't see the glow coming from our bodies. Yep, we're bioluminescent just like some deep sea creatures. The only difference is that our glow is so weak that only very sensitive capturing equipment can actually see it. Oops. Time's up. Got a glow. Here's a young man in a business suit. He's got a secret. He's in the bathroom standing in front of the mirror washing his face with cold water to cheer up. There's no one else here besides him. But he's not alone. The guy looks nervous. He slaps his cheeks, looks in the mirror, and says, "Don't worry. We can deal with it. We've been going to this for so long. We will win." He said we not because he has a split personality. And no, he's not talking to someone else through a small microphone.

He said we because he knows a secret.

Technically, he's not all human, but a group of billions of living creatures. Him, you, and all the people on Earth aren't really who they think they are. Only 43% of your body is made up of human cells. The remaining 57% are microbes and bacteria. Now this guy is going on stage to tell us this secret.

Get on the scales. See the number? Now subtract a little more than half from it. This is your actual weight.

Everything else is microscopic organisms. It's hard to believe because in this case, your body should constantly change its shape, disintegrating into tiny particles. You would see your skin pulsating and continually moving. Fortunately, this doesn't happen for two reasons.

Firstly, microbes are tiny. Their movements aren't visible. Secondly, most of this microbial world is in a dark place we can't see. A place without access to oxygen in our intestines. It's where billions of little creatures are roaming. Feeling kind of crowded, huh?

Some of them appeared before we were born, but most were colonists who came with food and water. On your body surface, all microbes come from the environment. Every corner of your skin is covered with microbes. No matter how you try, it's impossible to get rid of them. There are more microbes than human cells. Our genome consists of about 20,000 genes. The number of microbes genes in the human body is about 2 to 20,000 million. That means that technically we're not people, but microbes. Fortunately, it's not so bad.

The genome of microbes complements our own. Such a model of existence reveals many opportunities for medicine. The human microbiome includes bacteria, fungi, and other microorganisms. All of them divided into many species, and each type performs its own functions. Some microbes are responsible for vitam. Others help the breakdown of destructive substances. Another type helps your tummy digest food. A separate group regulate your immune system, protects it against ills, parasites, and viruses. Some control weight. Simply put, microbes make your life better, help your body function, and affect your health. There are microorganisms that provoke many diseases. They impair immunity or affect vital organs. Imagine you know exactly which bacteria are responsible for feeling unwell. Next, you find a way to rid yourself of them.

It can be some pill with poison against those microbes. You drink it and the cure erases all the harmful pests inside your body. A disease might appear because of the lack of beneficial microbes. This is one of the ways doctors heal many people in the world.

Now, let's say you've determined a group of microbes that help strengthen muscles. Then you find out which trace element helps these bacteras work faster and more efficiently. You add this vitamin to food or just get a pill containing a billion of these microbes.

As a result, your muscles grow twice as fast. The presence of some microbes or the lack of others can show the state of your entire body. A sample of your microbes can indicate your level of health or the presence of some disease.

Any person can improve their body not only with the help of genetic engineering but with microbial medicine.

Studying human microbes is cheaper, more efficient, and faster than expensive complex gene modifications. This area is just beginning to develop all over the world. But there are already some discoveries. Previously, humanity thought microbes were enemies. We made up many ways to destroy bacteria and viruses. But along with the harmful germs, these cures get rid of the good ones. Now scientists understand that microbes can both take away and save lives. So they started large-scale research on this subject. Let's have a look at a big panda. This animal with an ample supply of fat under its skin is omnivorous. It rarely eats meat. Its diet mostly consists of berries and bamboo shoots. But in winter there's none of this. So pandas feed on bamboo leaves. That food is low calorie.

There's almost no proteins in it. But still, pandas don't lose weight after a cold winter. Recently, scientists found out how pandas do that. It's all thanks to a unique microbiome. Every winter, a lot of unique bacterias are born in their intestines. These microbes extract and synthesize helpful substances from bamboo leaves better than others and thus preserve the panda's weight.

Scientists put these bacteria inside field mice. Small rodents began to gain weight much faster. Hamburgers, cakes, and other heavy foods contain calories and help develop colonies of microbes that contribute to weight. Millions of species of microbes have millions of functions. In theory, each of these functions can be used for the sake of humans. So, imagine you need to lose or gain weight and you just add these microbes to your lunch. Do you want to sleep better or fight drowsiness? Drink microbes that will affect the production of sleep hormones. Do you want to strengthen the bone tissue? Yeah, no problem. Bacteria are not only inside our bodies. They're everywhere. Part of the planet is made up of microbes. These tiny organisms are constantly multiply.

Look, there are a trillion of them on your keyboard. One bacterium increases in size and splits into two bacteria.

After a few minutes, these two increase and divide again. Four microorganisms appear. Each of them splits in two. The colony of bacteria is rapidly growing.

With such quick reproduction, one microbe can make one ton of offspring in just 24 hours. After 5 days, bacteria will fill all the seas and oceans. They will weigh more than the whole planet.

Under ideal conditions, bacteria could take over the whole world. However, this will never happen. There are no such perfect conditions for uncontrolled bacterial growth. The speed they multiply at is equal to the speed of their destruction. Dryness, water, light, high temperature, gases, humidity, all these phenomenon help control their population. At the same time, microbes are in charge of most of the chemical reactions on Earth. An old apple on the ground is rotting because of germs and bacteria. Mold forms on bread because of microorganisms. But they don't just exist and affect the condition of any material and other living creatures. An endless battle for survival continues in the world of microorganisms. Giant bacteria absorb smaller ones. Microbes with spikes defeat long microbes. There are also viruses that penetrate bacteria and infect them with their cells. A small ball with a virus can destroy an entire colony of microbes. Viruses multiply and take over more and more territories until they meet strong immune cells on their way. There are also creatures resembling robots. They look like diamonds with mechanical legs. Despite this unusual appearance, they're 100% natural. We call them bacteria phasages.

They have only one purpose, to destroy all bacteria. Bacteria phasages are additional protection of the planet from uncontrolled reproduction of microbes.

When some microorganisms multiply, they leave decay waste. This waste is harmful to humans. Bacterial phasages fight these microbes and save our lives. The coolest thing is that these defenders don't seek to take over the planet. They only attack bacteria. Every second, billions of microbes battle with billions of bacterial phasages on any surface. Sounds like a video game. The crystal headed jumps on the bacterium and injects the genetic code inside it.

This code has separate elements that connect to each other inside the microb's body and becomes a new bacterial phase. Then it destroys the bacterium from the inside and goes for the next one. Look closely at your fingertip. There's a lot of life there.

The strongest survive, the weak disappear. Wash it off and new bacteria will come along with the water. Wipe your wet finger with a towel and new germs will jump on you from there and the battle will begin again. This is just the tip of your finger. Inside your body, some bacteria are fighting for your health against microbes that want to harm you. Some microbes in our intestine can be responsible for a good or bad mood. There are also parasitic bacteria that can affect our brain, the way we think, and our emotions. Some creatures control the behavior of animals and insects.

Scientists constantly make discoveries in the world of microorganisms.

So bacteria are the rulers of our world.

They appeared long before humans and the first animals and most likely they'll remain after us. Think about that. So you have a six sense. It tells you where the various parts of your body are in space. Thanks to it, you can walk up a flight of stairs or touch your nose even with your eyes closed. Your vocal cords only produce a buzzing noise. Your nose, mouth, and throat determine what your voice will sound like. If you have a deep voice, your vocal cords are thicker, and your cavities are larger than average, letting the sound resonate. By the time you wake up, you'll have forgotten 50% of your latest dream. After 10 minutes, you won't remember 90% of it. When you blush, your stomach lining goes red along with your face. It happens because your sympathetic nervous systems causing an increased blood flow throughout the body. Your hair follicles have the same receptors as your nasal passages. That's why your hair can detect scents, too.

Sandalwood can help you develop that superpower. Out of 5 million hair follicles on your body, only 100,000 are indeed on your head. An average human will have eaten 35 tons of food over a lifetime. That's like three school buses. No matter how hard you'll try, you'll never be able to tickle yourself.

is because your brain prepares the body for tickling and helps you avoid the typical laughing I'm sorry typical laughing reaction. One human hair is so strong it can hold up to 3 and 1/2 o. If only the scalp were that strong as well, you'd be able to hold the weight of two elephants with your hair. Your eye has 256 unique characteristics and your fingers just 40 of them. That's why retinal scanning is more reliable than fingerprint scanning. 50% of your hand strength is in your little finger alone.

Yet, the thumb is the most important finger. You wouldn't be able to grip without it. If you stretch out your arms to the sides, the distance from the middle fingertip of the left hand to that of the right hand is equal to your height. An average human produces enough saliva to fill two swimming pools over a lifetime. Hey, dive in. Your spine has a great memory. It remembers your posture, making it so difficult to change it for the better. You owe goosebumps to your ancestors for many, many, many years ago. Their hair used to stand up to make them look bigger and scarier to foes.

Cats hiss and arch their backs for the same reason. Your left lung is a little smaller than your right lung to make some room for the heart. The right lung has three loes and the left one just two. Both of them are protected by your rib cage. Next time you get the hiccups, try bending over in a chair. Drinking from the far side of the glass also helps get rid of them. You can easily survive without your appendix, stomach, one kidney, or one lung. Hey, nice to know we have spare parts. A human eyebrow lives for about 4 months. After that, you get new ones. You, along with other humans, have the superpower of glowing in the dark, especially in the late afternoon. Your face has the strongest glow. Still, it's too dim for your eyes to pick it up unaded. The beating sound of your heart is in fact the clap of the valves inside opening and closing. The lyrics for that are loved dub love dub. You can't breathe and swallow at the same time. While you're breathing, the pipe leading to your stomach shuts down. When you're swallowing, the gateway to your lungs temporarily closes. Under 1% of all people are born with their hearts on the right side of the chest and not the left one. You blink 15 to 20 times per minute or 30,000 times a day. Your eyes have the fastest muscles in your entire body.

They slow down to five blinks per minute when you're looking at a computer screen. Your eyes owe their color to a pigment called melanin. People with brown eyes have more melanin than greeneyed individuals. If you have blue eyes, it means the eye tissue is completely colorless. Your eyes get color just like water in the sky do.

They scatter light and reflect blue light back. The first known person with blue eyes was born in the Stone Age around 7,000 years ago. I wasn't around then. There are about 3 million sweat glands in your entire body. Many of them are on the soles of your feet and on your palms, forehead, armpits, and cheeks. With every sneeze, the air is traveling out of your nose at a speed of 100 mph. There's no wax in your ear wax.

It's made of fat, skin cells, sweat, and dirt. Yum. Before you try to get rid of it, remember it protects the ear from bacteria, dirt, and dryness. Stress and fear boost its production. If someone made a camera out of the human eye, it would have a resolution of 576 megapixels. Your brain can hold up to 25 million gigabytes of data. Not my brain.

You swallow every minute while you're awake and three times per hour when you sleep. That sums up to 600 swallows per day. Gulp. If you're left-handed, you most likely chew on the left side, and if you're right-handed, on the right side. Your fingerprints will always find a way to grow back their unique pattern, no matter how bad you damage them. Every human has a unique pattern of ridges and furrows in their ears. They also sound different thanks to microscopic hair cells in your inner ears. You need a powerful microphone to pick up the noise they produce. The way you walk is your unique feature. Machines can easily distinguish your individual tiny ticks, bounces, and ways of swinging your legs you use with every step. Your sense of smell helps you taste 80% of the flavor of any food. That's why it seems so dull when you hold your nose or have a snack while traveling by airplane that makes your sense of smell weaker. Women are better at remembering faces and tasks for the future, but easily forget what has been done. It's the opposite for men. Your eyes can change color as you age or even depending on your mood or dieting habits. 300 billion new cells are born in your body every day. Now that's recycling. Your fingers don't have a single muscle in them. Their joints move thanks to the muscles in the palm and the forearm. Your fingernails grow faster than your toenails. That's because you use them more actively and they get more sunlight and air. Your eyes send a 2D upside down image of the world to your brain. It quickly corrects it and turns it into a 3D right side up image that it's used to. There's more nerve cells and connections in your brain than there are stars in the Milky Way. If you decided to count them all, it would take you 3,000 years. To make it easier for you, you have around 100 billion neurons in there. The space between your eyebrows is officially called gloella. You're taller in the morning than in the evening. Gravity makes the cartilage around your bones compress over the day, making you shorter by the time you go to bed. In case you're right-handed, your fingernails on the right hand grow faster than your left one. That's because you use this hand more often and are more likely to damage it somehow.

Your body is trying to protect it and sends more blood and nutrients its way.

If you walk a healthy amount of steps every day, you'll have covered 100,000 m by the time you're 80. It's like circling the equator four times. The largest muscle in your body is the glutius maximus at the back of the hip and you're sitting on it. But never mind. The tiniest muscle in your body is in the middle of your ear. Its main purpose is to stabilize the stapes, the tiniest bone in your body. It takes care of transmitting sound waves to your inner ear. You spend about 5 years of your lifetime eating and onethird of your life sleeping. An average adult weighing 150 lbs has a skeleton weighing about 21 lbs. So, I guess the remainder is meat and stuff. Your heart beats over 2.5 billion times over your lifetime.

Your skin thickness is different throughout the body. You have the thickest skin on the palms of the hands and soles of the feet, and the thinnest is on your eyelids. It takes your skin cells 28 to 30 days to completely renew themselves. Even if you only have less than half of your liver left, it can still regenerate to its original size.

Your taste buds only live for 10 to 14 days. Then they renew. Then what?

Everything tastes fresh. Even when you're resting, your brain uses more than 20% of your body's energy to keep it going. The brain's main function of processing and transmitting data is really pricey when it comes to energy costs. Your big toe bears 40% of your body's weight. Without it, running and walking would be slower, shorter, and less efficient. Thanks to zero gravity, your discs in between each vertebrae expand when you're in space. That's why you can grow up to 2 in taller. An average adult body is home to seven octillion atoms. That's 7 billion billion or 7 followed by 27 zeros. Do the math. A caterpillar has more muscles than you do. It's 4,400 versus 650. Your peripheral vision is almost completely black and white. It's because you have more color detecting cones in the center of your retina than at the sides. An average adult human body has enough fat in its cells to produce seven bars of soap. Your sweat itself doesn't smell like anything. The bacteria living on your skin mix with it and give it that notorious smell. You get red eyes and photos because when the camera flash goes off, your pupils don't have enough time to constrict. A large burst of light reaches your retina and it bounces back. Your legs feel leavy when you're afraid because of the adrenaline that gets in your system. It turns on the fight orflight reaction. Your body sends blood flow to your most needed areas to let you take action and protect yourself. Women can distinguish more colors than men because they have two X chromosomes and men only have one. Even if something is wrong with one of the chromosomes, a woman can still see colors correctly. That's why women are rarely colorblind. No matter how slim or plump you are, you have the same exact amount of fat cells as everyone else.

When you work out and diet, they don't go anywhere, but shrink in size and can grow back again. All muscles in your body are connected to bones at two ends to be able to pull and create motion.

The only exception is your tongue. It's connected to a part of your neck on one side and is free on the other side, so you can make funny sounds.

The weird-l lookinging flies you see right in front of your eyes every now and then are eye floaters. You see them because of tiny structural imperfections in one particular part of the eye that get in the way of life. They get worse with age. Oh, goody. An average woman speaks about 20,000 words a day, while an average man only speaks 7,000 words.

That's because the brain region responsible for language skills and social interactions is larger in females. Your hands and feet alone would look rather creepy. They also contain more than half of the bones in your entire body. Each hand has 27 bones and each foot has 26. Your thumbs have their own pulse because there are big arteries inside them. That's why you can't feel your pulse in the neck with your thumb.

You spend 10% of the time when you're awake with your eyelids closed. It's all those times you're blinking. Humans are capable of using echolocation like bats and dolphins. With some training, you can find your way in complete darkness, analyzing the surroundings by sounds bouncing off objects. Oh, need to practice that. On average, it takes 7 minutes to fall asleep. There are some techniques to speed up that process to 120 seconds, though. You can physically see your nose, but the brain chooses to ignore it. Otherwise, it would stand in the way of your vision. Plus, it would be out of focus. Around 12% of people can't dream in color. There used to be more of them before color TV had been invented. All your muscles relax at the same time right after you've fallen asleep. Your brain thinks you're about to fall and sends quick signals to all of your muscles to awaken them. That's why it sometimes feels like you're literally falling. You've inherited fingers that get wrinkly from water from your ancestors. It gave them the grip they needed to survive in rainy weather.

Your toes get wrinkly, too, to let you stand on a wet surface safely. Many centuries ago, people used their wisdom teeth to chew through tough plants and roots. As their brains grew bigger, leaving less space in the mouth, these teeth became the extra ones. Now, you can just cook your food and survive without them. Every day, an average woman unknowingly puts on about 515 chemicals on her body. They come from deodorants, shampoos, conditioners, moisturizers, and other beauty products.

Most of them are harmless. You can't sneeze when you're sleeping because the nerve cells in your nose that activate sneezing are sleeping, too. You can't sense smells in your sleep, either. An average person has around 250 hairs per eyebrow, but some lucky fellows have a total of,00 hairs. They keep raindrops and sweat from getting in your eyes.

Your skeleton completely renews itself every 10 years or so. The process never stops but slows down with age. That's why your bones become thinner. An adult takes 12 to 16 breaths per minute. It adds up to a total of 17,000 to 23,000 breaths daily. If you stretch your entire network of blood vessels, its length would be enough to circle the earth twice. That's over 60,000 m. And you would be very sore if you did that.

Women have more taste buds on their tongues than men. 35% of women are super tasters and have more than 30 taste buds in the space the size of the hole punch on their tongue. That's an interesting comparison. Sugar is sweeter and sodium is saltier to them. Blondes have the biggest number of hair follicles, around 146,000. Second place belongs to blackhaired people. They have 110,000 follicles. If you have brown hair, there are around 100,000 hair follicles on your head. With an average of 86,000 follicles, red heads have the least dense hair. As you age, your feet might get bigger, but it doesn't mean your bones are growing. It happens due to weight gain and loose ligaments that make your feet flatter and wider over time. When you have that stomach in your throat feeling on a roller coaster, some of your organs are really shifting. It happens to your intestines and stomach which are connected rather loosely and is harmless. It says here your teeth have enamel on the outside that makes them just as strong as a sharks. They aren't as sharp though. Your hair can stretch about 30% of its length when wet. Your brain constantly needs oxygen and uses 20% of its reserves in your body. When you're trying to solve some problem, it can even use more oxygen up to 50%.

If you decided to smooth out all the wrinkles in your brain, it'd be a flat surface the size of a pillowcase. As you're listening to music, your heartbeat sinks with the rhythm. Faster tempos make it beat faster. Your diaphragm sometimes twitches, which makes you suddenly intake more air. Your throat closes and interrupts the intake.

This is how hiccups work. Unlike what every space movie tells you, you won't instantly freeze if you got into open space without a suit. Space vacuum is a great insulator. So you would retain your heat for some time. Just don't make a habit of it. The atoms in your body are billions of years old. Nearly all of them were made in a star and many have come through several supernovas. It makes you a big chunk of stardust.

Scientists still don't know why humans yawn. The most popular theory says it happens to cool down your brain and regulate body temperature. Humans are the only animals that have chins. Even chimpanzees and gorillas have lower jaws that slope down and back from their front teeth. When you're breathing, most of the air is going through one of the nostrils. After a few hours, it starts going through the other, and they keep switching like that. Your nose can pick up about one trillion smells with 400 different types of scent receptors. The sound you hear while cracking knuckles are gas bubbles bursting in your joints.

Ooh, more fun body sounds. You burn calories when you're just breathing, watching TV, and even sleeping. By the time you turn 60, you will have lost almost half of your taste buds. That's why most elderly people don't notice the unusual or bitter taste. It only takes you 0.05 seconds to recognize a sound.

That's 10 times faster than blinking.

It's virtually impossible to destroy a human air. Water, cold, and corrosion can do nothing to it. The only way to go is to set it on fire. Nah, don't do that. Around 1% of people are missing a special lens in the eye and can see ultraviolet. Famous impressionist painter Claude Monaet belong to that 1%.

When you sleep in a new place, half of your brain stays awake. Thanks to that, you'll be able to quickly get up if you have to protect yourself from something or someone. The way your sneeze sounds depends on your nose size. The larger the nose, the bigger the sneeze because more air can go in and out. All the strangers from your dreams are real people you've met at some point in real life. You just didn't remember them.

Unlike other cells, neurons can't replace themselves. If you typed 60 words per minute for 8 hours a day, it would take you 50 years to type the human genome. That sounds like a big waste of time. There's a name for the dip between your upper lip and nose.

It's filtrum. Some people can navigate using the magnetic field of the planet, just like birds. Me? Nah, I can barely use my GPS. Hey, can you speak up? I just ate an entire pizza. That's because after eating a hearty meal, our hearing tends to be a bit less sharp. During digestion, most of our bloodstream is directed toward the stomach, which takes away a bit from all the other organs.

So, next time you want to go listen to your favorite band at a live concert, make sure to eat a lighter meal to keep your ears pitch perfect. On top of our stomach and left kidney, we have a magical organ that can grow back if we remove a part of it. Our liver can regenerate itself by making new cells called heptoytes. They begin to multiply once the liver is damaged. The seriousness of that damage defines if it can regenerate completely and the amount of time it takes to do so. Ever wondered what's worse for your body? No sleep or no food? Turns out the lack of sleep is more dangerous. That's because if you don't rest, your body becomes exposed to a lot more risks. After 24 hours without any shutye, you can start to have memory problems and find it difficult to concentrate. At just 17 hours without sleep, you start to feel tired and groggy, irritable, tense, and more emotional. I need a nap. Your pain receptors also become more sensitive, which means everything hurts a bit more than it should. Oh, and it also affects your hearing, too. What? On the other hand, you can be well into your 24-hour period with no food before your body realizes you've stopped eating. In the first 8 hours, you just keep digesting the last meals you had. After those first hours, you start to use stored fats for energy. Not eating for more than 24 hours means that your body will start eating away at its own protein, which means you literally start to lose muscle. Rain water isn't always safe to drink. It can sometimes hold harmful bacteria and viruses. Also, in heavily polluted locations, it may even meet other harmful materials. Some communities out there do depend solely on rainwater as their primary source of hydration. But does rain water have any other health benefits? Not really.

According to current studies, some of those risky substances may be removed from rainwater if you boil it, but it's best to stick to the safer side and only drink water from sources that are 100% safe for human consumption. Now, we produce sweat mostly to regulate our body temperature and for some added moisture, like the one we need in the palms of our hands for a better grill. But sweat doesn't just show up on our skin. It comes out of around 5 million pores on our bodies.

We're literally stepping on a quarter of our bones each day. We have just over 200 bones in our body, but about a quarter of those are in a very small surprising area, our feet. Since we have 26 bones in each foot, we end up with literally 52 in both.

Now, our eyes produce tears for many reasons, like protecting themselves from infection or clearing up debris, such as smoke and dust, or when your baby done you wrong. But the number of tears we produce is quite surprising. Up to 30 gallons per year. That's almost enough to fill a bathtub. Wow, that is heartbreaking. Our blood pressure wakes up hours before we do. That's because in the morning, the body produces a bunch of hormones like adrenaline and noradrenaline. They help give us the energy boost we need during our morning hours, but they also increase our blood pressure, which is usually higher between 6:00 a.m. and noon. During the night, since we should technically sleep and perform no physical activity, our blood pressure drops down by up to 20%.

Speaking of our vital fluid, our blood accounts for about 10% of our total body weight. We tend to think of our body weight as being mostly made up of muscles, fat stores, and bones, but there's a lot more to it. In a fit adult person, bones make up 15% of the total body weight. About 40 to 45% is left to muscles, about 15% to fat deposits, and the rest are stuff like skin, tendons, hair, and other yucky things. Let's say that adds up to, yep, 100%. Your lungs aren't twins, they're siblings. That's because they aren't the same size or shape. Your right lung is bigger and tends to weigh more, and your heart is to blame for it since your ticker tilts to the left a little bit.

This creates a small indentation in the left lung called the cardiac impression, which is also what funny heart doctors do at comedy clubs. The right lung may be bigger, but it's a bit shorter since it needs to make room for the liver.

Doesn't your house have a liver room?

Many of your body measurements are quite symmetrical in surprising ways. If you were to stretch out both of your arms, your wingspan, and measure it, it should show how tall you are. Based on these similar measurements, specialists can even produce theories about what ancient humans used to look like. Looks like we've evolved to be increasingly symmetrical to appear more attractive and healthier to attract mates. H more so, since we've evolved to also walk on two legs, our symmetrical features help us to move around with the least amount of energy because it creates balance.

Now, humans aren't natural champions when it comes to the scent of smell.

That's for sure. But our noses can pick up about 1 trillion different scents.

Scientists are still performing research on this subject and believe the number may be even higher. Some dog breeds may be able to notice sense somewhere between 10,000 and 100,000 times better than we do. But turns out the best nose in the animal kingdom may be attributed to the elephant because of its staggering number and type of receptor genes over 10,000 while humans and chimpanzees have less than 400.

We tend to look at our pinkies as our most delicate fingers, but we do have more power in them than we think. Turns out that should our pinky finger be lost or affected, the overall strength of our grip may decrease by up to 33%.

The liquid in our stomach made of hydrochloric acid, potassium chloride, and sodium chloride is way more powerful than any acidic food you can think of like lemons, pineapples, or tomatoes.

The pH of healthy stomach acid should be between 1 and three. So, if you think about it, it's just below that of battery acid. Our hair strands are strong, too.

so strong that research is performed on them to duplicate their resistance into human-made materials. A healthy head of hair should be able to withstand up to 26,000 lbs. It's due to a little protein in the hair strand called keratin, which you can also find in your nails and skin. Now, only about 1/3 of us humans have perfect vision. There are a lot more glasses and contacts out there than you'd think, making up about 66%.

Apart from different eye conditions, our vision also gets worse with age. When we're born, our heads amount to one quarter of our total length. By the time we reach 25, our head will only be 1/8 of it. That's because our heads won't change their size a lot as we grow older, as opposed to the rest of our body, mostly when it comes to the legs and torso. Our brains are these super powerful computers and a single human brain cell can hold five times as much information as the entire encyclopedia bratannica. Maybe you remember that.

We've yet to pinpoint the exact amount of data it can support, but in electronic terms, the storage capacity of the brain is around 2,500 terabytes.

For comparison, the National Archives of Britain, which keeps over 900 years of history, only takes up 70 terabytes. That's probably the reason our brains need the most amount of oxygen compared to other organs. About 20% of the total oxygen that enters the bloodstream. And that's despite the fact that it makes up only 2% of our body mass. Our normal activities plus the effect of gravity make the cartilage in our ankles, knees, hips, back, and neck slowly compress. Once you rest overnight, the cartilage goes back to normal. On average, you are somewhere around 4 in taller in the morning than you are later at night. And that's why they call me [Music] stretch. The human tongue consists of eight intertwined muscles. The whole structure resembles an elephant's trunk or an octopus tentacle. Just like them, the tongue is very flexible and can move in any directions. People who live to be 10 years and older, also called super centinarians, may have a secret.

Researchers have discovered they have more immune cells called t-helpers than the average person. These cells are likely to protect some people from some health problems. Scientists have always thought that the human brain is a sterile place free of germs or bacteria. But the latest studies have shown that experts might have been wrong all along. It seems there are harmless microbes living in our brains. But researchers need a bit more time to make sure.

Researchers believe that if people suddenly started to be born with six fingers, the brain would easily adapt to it. Those with polyactilly extra fingers or toes usually don't have any problems with this feature. Their brains know how to control additional fingers and how to use each of them independently. Such people sometimes need only one hand to carry out a task for which others would need two hands. In some people, saliva accumulates in a gland under their tongue. It can then get propelled out in a stream when a person presses on this gland. If the mouth is open at the moment, a jet can reach several feet.

This process called gleeking can occur spontaneously. A person accidentally pushes their tongue against the gland while eating, yawning, talking, or cleaning their teeth. And voila, up to 35% of people can bleak. But just 1% can do it on command. About 25% of people have an interesting reaction to sunlight. I mean sneezing. This phenomenon has its own name, the fodic sneeze reflex. In the Greek language, it's called sun sneezing. Just like salamanders regrow their tails, humans might be able to regenerate cartilage. That's rubber-l like stuff around your joints.

Scientists have discovered that cartilage is likely to repair itself most effectively at the ankle, not that well in the knee, and least effectively in the hip. The older you get, the fewer bones you have. When people are born, they have many more than 206 bones. In babies, most bones look different than they do in grown-ups, and there are more than 300 of them. Where do those extra ones go? They sure do not disappear or dissolve. They fuse together as they develop until they merge. Some bones contain neither collagen nor calcium.

What we think is standard bone material.

No, they start as flexible yet tough cartilage. Later the cartilage turns into sturdier bones and some of the pieces come together. For example, the skull initially consists of 44 different elements. But a grownup skull is made up of 22 bones. Some bones don't fully form till our early to mid20s. When someone's lying, their own nose gives them away. Psychologists from the University of Granada discovered that when a person told a lie, the temperature around their nose and the inner corners of the eyes went up. This phenomenon was called the Pinocchio effect.

Ancient Greeks had stories about fireb breathing creatures called chimeas. They were a fearsome mixture of a god, lion, and snake. In real life, chimeas are people who have two different sets of DNA. Scientists have recorded no more than 100 cases of human chimeism. Albanism is a rare feature to have. People with albinism have very little to no melanin, a substance that produces pigmentation. But if it's ocular albinism, that's even more unique. This kind of albinism affects only a person's eyes. Experts don't have exact numbers, but they think between one person in 20,000 to one person in 50,000 have ocular albinism.

Scientists have figured out that you might be good at hearing things thanks to a teeny jello violin. Inside your ear, there is a miniature assembly line of nerves, tissues, fibers, and bones.

It turns vibrations into sounds. And there is also a blob of jellyike substance made up of 97% water. Researchers believe that thanks to this jello, your ear can separate high frequencies from lower ones.

Your brain is constantly processing tons of visual information around 600 million bits per minute. It all starts when the light goes through the cornea. Your eyes clear protective outer layer. After several transformations, the light turns into electrical signals. They travel to your brain and it interprets them into images you see. It takes milliseconds for this super complicated process to happen.

The human brain is 73% water just like your heart. That's why if your brain loses even 2% of liquid, you start feeling exhausted. This also makes your memory worse, shortens your attention span, and puts a dampener on your mood. Around 65% of the world's population have loop-shaped fingerprints. In 30% of people, fingerprints are whirl shape. And only 5% of people have arch-shaped fingerprints. All these types are divided into smaller groups. For example, there might be plain or tinted arches, accidental whirls, or the peacock's eye, and so on. If you have a circular hair whirl on your head, it's likely to be clockwise.

Some scientists think there is a genetic link between hair whirl direction and handedness. A bit more than 8% of right-handed people have counterclockwise hair whirls, but in the left-handed, this number grows up to 45%. There are more than 650 skeletal muscles in your body. They make up around 40% of your body weight. Up to 85% of the heat your body produces comes from your muscles contracting. At the same time, caterpillars have many more muscles than people. some species, up to 4,000 of them, and the grasshopper has 900. Your brain can decide what sounds to focus on when you're in a loud place.

Thanks to this ability, you can shut out all other voices and concentrate on the person you're listening to. The Bajger is a group of nomadic people that live in the waters around the Philippines, Indonesia, and Malaysia.

Thanks to a rare DNA mutation, they can stand in water for up to 13 minutes. The Baja people have evolved splints that are way larger than average. This feature provides them with a genetic advantage. See nomads needed to hunt for fish or look for underwater stuff that can be used in crafts. Human bones might be loaded with a network of tiny tunnels. Scientists knew nothing about them until recently.

That's why it was unclear how blood cells which are produced in our bones could quickly exit bones and get into the blood circulation. But now the mystery may be finally solved. If there are holes, there can also be capillaries, miniature blood vessels. Some people have more than one row of eyelashes. This phenomenon is a genetic mutation called disticasis. A person with this condition has a second set of eyelashes growing behind the first. All these thick lush lashes sure look beautiful, but they can also cause some discomfort. Some hairs can start growing in the wrong direction or in the place where an oil gland is supposed to be. It can cause irritation and tearing. Why do your fingernails turn blue when you get cold? For one thing, your fingers are rather far away from the rest of your body. Just like your toes or the very tip of your nose.

Imagine a piece of tissue in the middle of your body. It gets circulation from all sides, left and right, up and down.

But the ends of your fingers have just one option. Blood can only flow from the hand down the fingers. When it's cold, little blood vessels, aka capillaries, in your fingers narrow. It prevents blood from flowing as freely as before.

When blood circulation slows down, the tips of your fingers and your fingernails don't get enough oxygen rich blood. And the less oxygen your blood contains, the darker it becomes. Its color is actually dark red, but we perceive it as blue. The hippocampus is a part of your brain that helps you navigate in space.

You have two of them, each the size of a chestnut. London cap drivers have bigger hippoc campai than most other people.

Researchers are sure it's thanks to their regular mental workout. It's not a gimmick to navigate 60,000 London streets. Your dog doesn't actually have a stronger sense of smell than you do.

People often talk about how dogs have a superior sense of smell. And this probably started when a researcher from the 19th century, Paul Broca, marked humans as non-smellers. No one ever provided sensory testing to support this theory, but people still believed in it for a long time. The truth is different types of animals can identify different kinds of scents. There was an experiment done where human volunteers needed to track a scent. Researchers dipped twine in chocolate essence and then zigzagged it all across a grassy field. Volunteers weren't allowed to use other senses. For example, they were earmuffed and blindfolded. They even wore thick gloves and knee pads. The conclusion they came to is that while we are not as effective as dogs, we can follow a scent trail and become way better if we practice.

Interestingly, humans are more sensitive to certain smells compared to dogs like fruit or flowers. This is because the evolution of dogs didn't require them to sharpen their sense of smell for these types of odors. A TV screen won't ruin your eyesight. At least, there's no evidence that looking at a TV screen can really hurt your eyes. It's the same for phone or computer screens. Looking at them may lead to eye strain or fatigue, but in most cases, it's nothing you can't ease with proper rest. That doesn't mean watching TV or staring at your phone for too long doesn't have negative consequences in other parts of your life, like reduced concentration and lack of socialization, among many other things. Being able to roll your tongue is not really a genetic trait, even though biology teachers often say this gift is based on a dominant gene.

There was a study that showed seven out of 33 twins who didn't actually share this feature. Identical twins share the same genes, which implies that they should share this trait, too. But they don't, which means genes are most likely not the factor that decides if you'll be able to roll your tongue. And this myth still exists even though it was debunked over six decades ago. You're going to catch a cold if you go outside with wet hair is yet another myth. To actually catch a cold, we need to have a virus inside of our body. Also, wet hair is not something that makes you more attractive to the various germs lurking around you. People mostly believe this is true because they a heard it from their parents and b ass associate going outside with your hair being wet with getting sick because you're generally more exposed to germs when you're outside. There are no truly double-jointed people. Some individuals have certain parts of their bodies that are very flexible, so they can, for example, touch their chin with their elbow or bend their fingers backward. We often call these people doublejinted like the secret is in them having an extra hinge somewhere. Well, it's not true. They have single joints, but they may have bones with oddly shaped ends or their connective tissue may be very pliable. It seems the appendix, as in the organ, is useful after all. Despite its poor reputation as a useless intestinal tube that pretty much goes nowhere, it seems the appendix is actually a reservoir for bacteria, but a good and helpful one. It stores microbes that assist our body when it's fighting certain problems and illnesses. In the early stage of our life, the appendix also helped us with the process of forming white blood cells together with certain types of antibodies. Hey, do you know where the stomach is? Huh, sounds easy, right? But it's probably not where you think. Most people believe it lurks somewhere in the area behind the belly button. In reality, it's a bit higher in the abdomen, sitting on top of the rest of the gut. Here's how you can find it.

Look for the point where your lower ribs meet in the middle. Now, go down approximately three finger widths and then three to your left. Now, you're supposed to be right over the center of your stomach. You don't have taste sections on your tongue. The tongue map probably showed up at the beginning of the 20th century because scientists found minute differences in how strong a taste had to be in different areas inside the human mouth to actually register. This study created a myth that each part of the tongue was responsible for different tastes. In reality, all types of taste buds are spread across all areas of your mouth, and they can detect each taste. This includes umami, too, which is now accepted along with the usual four: sweet, salty, bitter, and sour. We don't only use 10% of our brain. We use way more, even when we're sleeping. Scientists tested this statement and one of the methods they used was measuring activity in the brain while a person was performing various tasks. Results have shown we use most of our brain most of the time. The exact percentage varies from person to person depending on what they're doing. Plus, it's not possible to monitor every single one of our brain cells. There are billions of them after all. So you can't know the exact number of active ones at any given time. When asleep, your frontal cortex, the part responsible for let's say higher level thinking and certain areas that help you sense your surroundings are still working. Humans don't just have five senses, hearing, taste, touch, sight, and smell. This idea originated from Aristotle, a famous Greek philosopher who said that there was a sense organ for every sense, eyes for seeing, a tongue for tasting and so on. But that was thousands of years ago.

And he was missing the vestibular system, a key sense organ. The vestibular system is the apparatus of the inner ear that our body uses to stay in balance. Not every sense requires its own sense organ, just a different type of sensory receptor. For example, your skin alone has four different receptors for temperature, touch, pain, and propriioception. Proprioception is body awareness, which means that even if you move your arm behind your back, you still know it's there. Something an octopus, for example, doesn't know. So saying we have 33 senses could be closer to the truth, not five. These include senses of balance, temperature, thirst, and many more we need to survive. If you like cracking your knuckles from time to time, no need to worry. The whole idea that it increases risks for potential knuckle problems perhaps makes sense in the first place because that's what happens when you constantly put pressure on your joints over the years. The satisfying sound you hear happens because of bubbles bursting in the fluid that actually lubricates your joints called synenovial fluid. If you eat a big meal, you can still go swimming. You won't get cramps. The idea behind this misconception is eating a heavy meal will increase the amount of blood flow to your stomach. That way, blood won't go to your muscles, which will potentially cause cramps if you go swimming. The truth is, you probably won't feel that comfortable swimming immediately after eating a large meal, but you're safe to go if you really want to. It's even recommended to have a small snack that's rich in carbs not long before your swimming session. This will boost your energy. When you shave your body hair, you don't have to worry about it growing back darker and thicker. Because this is a myth, you may believe there are some changes in the color, thickness, or growth rate of the hair. That's because after you shave, you give the follicle a blunt tip, which may look or feel darker and rougher than it was before. But that's just a perception trick. You'll see that once your hair grows in again, it will be the same as before. It's a myth that we lose a disproportionate amount of body heat through our heads. You may feel like that because our head, chest, and face are definitely more sensitive when it comes to changes in temperature. In reality, you'd be just as cold if you went out without a hat as if you weren't wearing pants. You probably feel like you're losing heat through your head because it's often one of those parts that we leave uncovered when going out.

No need to worry if you wake up a sleepwalker. You're not going to seriously harm them by doing so. If you startle one, they can be quite disoriented and may have a confused reaction. Sometimes it's better to do that than to let a sleepwalker get up and start doing certain things that they shouldn't be doing while sleeping, like cooking or driving. Or you could just show them the way back to bed. Yep, I think it's safe to say that falling from any height can be really dangerous, but especially when you've tumbled out of an airplane and worse without a parachute.

Now, the trick here is to create drag to slow your descent. Use your shirt, pants, or do an air snow angel. anything to slow you down a little bit. But hey, you've always wanted to make an impact, right? Well, check this out. A Yugoslavian woman was working as a flight attendant. She survived an incredible fall on January 26th, 1972.

After the plane she was working on exploded, falling from a height of 33,000 ft. She managed to survive, but spent the next year and a half recovering after waking up from her coma. Experts disagree on the right way to land, but there's definitely a wrong way. Landing on your head. Do you remember the rule of three for us squishy human beings? Uh, that's you and me, by the way. 3 minutes without oxygen, 3 days without water, 3 weeks without food. It's a great guideline, but some people manage to stretch it out a bit further. If watching a sunset, smelling flowers, or ordering that big juicy hamburger is important to you, well, you better start thanking that delightful gas oxygen. Don't believe me?

Try doing even one of those things without it. 2 minutes without oxygen will cause the average human to pass out. After 10 minutes, well, there isn't usually a comeback to her. This varies, of course, from person to person depending on their fitness levels, but we love to push the boundaries as humans, don't we? The longest someone held their breath for was an outstanding 24 minutes 3.45 seconds, give or take. That's 100 times longer than the first airplane flight. Take that, Wright, brothers.

Alex Sigura Vendrrell from Spain pushed the limits of breath holding in 2016 by floating in a controlled pool environment. Just before going under, he was gulping in air like a fish to try to get as much oxygen as possible.

Strangely, holding your breath underwater is easier than trying it on dry land. Swimming activates your divers's reflex, slowing down our heart rate and metabolism. Not only is oxygen important, so is precious H2O and tasty food. Each cell in our body needs water to survive. If we can't replace the water lost quickly, we only have about 3 days to a week before it's all over. How humid the air is, our age, physical activity, and health play a huge part in water retention in our bodies. When we're running low on water, the important areas of our body, like the heart and brain, pull water from wherever it can. Like a sponge, these organs soak up everything until there's nothing left. In 1979, an Austrian man in a holding cell lasted 18 days without water. He allegedly lick condensation off the prison walls to stay hydrated.

What's the scariest thing in the universe? The fridge is empty. Where's all the food? Without any calories, your body starts to feed on itself. Not exactly the diet I had planned for this year. During the first few days, our carbohydrate reserves are turned into glucose. When that's all used up, our body starts to target fat, muscle, and other proteins all the way down to the bones. Fasting is a common way to let our bodies use those extra reserves inside of us. Mahatma Gandhi's longest of many fasts lasted 21 days. The longest known fast was when a 27year-old lived off water and vitamin supplements for 382 days and shrank from 456 to 180 lb. Yow. Our bodies are equipped to survive without food for long periods.

Our ancestors didn't exactly have a supermarket to go to. This makes us pretty good at dealing with starvation.

We humans can cope with many extreme survival situations, but how long can you swim in freezing water without turning into a popsicle? What happens if you're stuck in the desert or at the top of a mountain? Climbing the peaks of the world, like the Rocky Mountains, the Swiss Alps, or even Mount Everest, is challenging on a good day. But the real danger is altitude sickness. It affects about half of all climbers, starting at roughly 1 and 1/2 m up. The lack of oxygen can cause dizziness, tiredness, and headaches for some. Others can even get insomnia. This is just the start of a whole bunch of symptoms that affect our bodies. Consciousness becomes a big problem for most people at 3 m up without proper preparation. Ascending too quickly can even lead to fluid in your lungs or even worse. The thing about altitude sickness is that it doesn't care if you're old or young, male or female, a couch potato or an athlete. Everest is 5 and 1/2 m high and the ultimate challenge for climbers.

That's like hiking up 20 Empire State buildings or two times the Hollywood Walk of Fame. Austrian Felix Bombgardner pushed the altitude tolerance limit on October 14th, 2012. He jumped from 128,000 ft up. That's nearly 24 miles.

It's no surprise that he's also the first sky diver to go faster than the speed of sound, reaching a mind-boggling 833 mph. He definitely had the right equipment, like a pressure suit with oxygen and safety checks in place, which goes to show you if you're going up high, remember the five Ps. Proper planning prevents poor performance.

Surviving extreme heat isn't just about the temperature. Humidity is the real danger to us. The less humid the air is, the more water stays where it belongs, in our body. Ever walked into the sauna and realized that it's over 230°. That's so hot and humid, you'd probably only last about 3 to 4 minutes max. Wait, humans can't melt, right?

Above 104°, there's a real chance of heat stroke. It doesn't sound like a big change from our usual body temperature, but it is. Just imagine getting caught in a desert for a few days. And not just any desert, the world's hottest. The hottest temperature ever recorded on Earth was in Nevada, a crazy 134°. Cooling way down really quickly can help relieve cramps, headaches, and even nausea. But breathing can become kind of impossible once your organs start to shut down and hypothermia sets in. As soon as our bodies drop below our natural body temperature, our muscles start to stiffen. That's why you stop feeling cold and pain after a while.

There just aren't any nerve endings functioning anymore. Shivering quickly to produce heat is our body's natural way to keep our organs warm. This only works for cold air, though. In cold water, shivering drains your body heat even faster. If you've never heard of the 300 club, you're not alone. A base in Antarctica has found a great way to test the extreme limits of the human body in the most peculiar way.

Participants at the station warm up in the sauna, which is heated to 200°. Then they pull on their boots and run outside where it's minus 100. Not only do they have to endure the 300° temperature change, but they've also got to run around the South Pole before coming back to the sauna to warm up again. Am I tired? Time for a little snooze. Sleep is very important. Maybe that's why getting out of bed in the morning is so tough. We need sleep to recharge our body from the long day we've just had, leaving us refreshed and alert when we hear that alarm. Our brain can turn all fuzzy without enough sleep.

And a good 8 hours is perfect for a healthy immune system. Sleeping improves our memory, our heart, and puts us in a better mood for the day. Randy Gardner and his friends tried to test the limits of staying awake. It was for their science fair project. They managed to stay awake and functioning for 11 days and 25 minutes. Even when tested during and after the experiment, Randy could play basketball and had no abnormal brain waves. Now, it's almost impossible to calculate the exact G force that would harm a human. That's because there are three types of geforce out there: side to side, up and down, and forward and backward. The danger lies in how long we have to sit there while we're being thrown around like a rag doll. The longer we sit there, the more it affects our bodies. We experience GeForce at home simply by sitting down on the couch too quickly, sneezing, or having someone slap our back a little too hard. Pilot John Stap demonstrated that a human can withstand over 40 G's. That's nearly 10 times the amount an average racing driver feels. The experiment only went on for a few seconds, but for an instant, his body weighed almost 7,000 lb. Survival isn't always about taking on the elements. Sometimes it's fighting against time. The current record for the longest living human is Jean Calman, who was born in [Music] 1875. The distance between your outstretched arms is your height. You renew your skeleton every 10 years. Time to renew. You lose around 100 hairs every day, and that's totally normal.

Humans are the only creatures who sleep on their backs for a long time. Koalas, like humans, have their own unique fingerprints. In a lifetime, the average person will walk the equivalent of three times around the world. A person can have from 250 to over 1,000 hairs in each eyebrow. Your eyebrows also have a lifespan, about four months, for all the hairs to fall out and be replaced by new ones. Thank goodness. Your eyes are the only organ that doesn't grow with age.

Human DNA is 96% similar to a chimpanzee, 90% similar to a cat, 70% to a slug, and 50% to a banana. That has a peel. You share 99.9% of your DNA with any random person on the planet. Your heart is the size of your fist. Your brain, two clench fists. When you listen to music, your heartbeat sinks with its rhythm. You can't swallow and breathe at the same time. Trust me on that one.

There are as many nerve cells in your brain as there are stars in our galaxy, about a 100 billion. The popular belief that people only use 10% of their brain power is nothing but a myth. Even when you're resting or sleeping, more than a tenth of your brain is working. You're more likely to get attracted to a person who thinks and looks the same as you.

The belief that opposites attract isn't true. Your nose and ears are the only parts of your body that never stop growing. The human brain generates enough electricity to power a small light bulb. If your eye was a digital camera, it would have a resolution of 576 megapixels. Your tongue prints are also unique to you, but let's not lick the scanner. Scientists at the University of Pittsburgh found that blue and greeneyed people are less sensitive to pain than browneyed people. But lighter colored eyes are more light sensitive than dark ones. The microorganisms in the human body outnumber cells 10 to one. I I about 6% of people can vibrate and rapidly shake their eyeballs back and forth. It doesn't mean something's not right with their eyes. It's just a unique trick they can perform. Good at parties, I suppose. Fun fact about bones. You know that your body is about 60% water, right? What's new here is that your bones are also in this, too. About 25% of human bone mass is made up of water.

Not all of your brain's regions are active all the time, but most work on this or that task 24/7. Every 2 minutes, people all over the world take more pictures than they did in the entire 19th century. However, there's nothing said about today's photos being any better. People are kind of programmed to return favors. This instinct probably developed when people needed to help one another to survive.

Studies have proved that sneezing is your nose's way to reset. A sneeze reboots the cells that line the insides of your nose. They're called psyia.

Sneezing is also one of the first defenses against bacteria and other, you know, unwanted stuff. When the delicate nose lining gets tickled with a foreign substance like pollen, dirt, or dust, it sends a signal to your brain. The brain informs your body it's time to sneeze.

The part of your brain that's responsible for vision is actually in the back of your head. The right side of your brain controls the vision on the left side and vice versa. Okay, put down your phone and pay attention.

Multitasking is actually impossible.

Your brain only allows you to switch between different tasks really fast, but not to do them at the same time. Such context switching isn't ideal either.

Studies show that in this case, people make mistakes much more often. Plus, they need twice as long as usual to do things. So, focus. There is one exception, though. When you're engaged in some physical activity you've done many times before, you can simultaneously perform a mental task.

That's why you can easily walk up the stairs or take a shower and think about problems at work. Now, food tastes better when someone else has made it.

That's why a sandwich from a cafe looks more appetizing even though you use the same ingredients. One study suggests it's because it takes time to make yourself a meal. So when you're ready to dig in, you don't feel all that excited.

Your body contains enough blood vessels to wrap around the planet 2 and 1/2 times. You spend 4 months in each year asleep. In a lifetime, you rack up 26 years. Only six of those years will be spent dreaming. We forget 50% of a dream within 5 minutes of waking up. 10 minutes later, it's 90%. Each cell in your body contains 1 and a half gigabytes of information. Do the math for your 100 trillion cells and see that you're one powerful walking computer. Your brain cools down when you yawn. Your ears work even when you're asleep, but your brain ignores the incoming information. The bumps on your tongue aren't taste buds. They're called pill. Not all pilli contain taste buds, but those that do that have one to five in each. The atoms in your body are 99% empty, and yet you feel full after dinner. Now, how is that? The brain grows for the first 18 years of life and then gets 5% smaller every 10 years after the age of 40. Well, that explains a lot, don't you think? We spend 10% of our waking hours with our eyes closed just from blinking. The muscles that work your fingers are actually in your forearm. Your foot is the same length as your forearm. Same ratio with your thumb and nose. Your toenails grow three times slower than your fingernails. Your lungs aren't identical. The right one has three loes and the left one has two.

Your hair grows faster when you're sleeping. The only thing that grows faster than hair is bone marrow. Your body releases enough heat in a half an hour to boil two quarts of water. Your brain uses 20% of the energy your body generates. Your body uses more energy to cool itself on hot days than to warm up when it's cold. People can go much longer without food than without sleep.

Stomach acid can dissolve metal. It's so strong that the stomach has to create a new lining every 3 to 4 days. So, what's eating you? Your stomach. In terms of muscle, your tongue is like an elephant trunk and an octopus arm. That's just wrong. Your nails are made of the same stuff as a rhino's horn and a horse's hoof. And the rhino wants it back. We have nails to protect our fingertips.

Without them, you wouldn't be able to grip things as well. You use 200 muscles just to take one step and 50 muscles just to use chopsticks. You use only two fingers to play chopsticks. Most people speak about 125 words per minute. The brain can process 800 in the same time.

me, I can go 185 with wind gust up to 250. Your skin completely renews itself every 27 days. Now, you can't tickle yourself. Your brain already knows of your intentions and prepares your body for it. Humans are the only species with an outline that separates the lips from the surrounding skin. Half the bones in your body are in your feet and hands.

Come on, let's share guys. Finally, cornflakes have more genes than people do. Your cereal has 32,000. You have 20,000. Your memory is affected by your body position. For example, you're much more likely to recall a situation where you wave to someone if you stand and wave again. Your brain has millions of neurons. They're all different. And the speed of the connection between them is different, too. That's why you can recall some information faster than others. The brain itself, by the way, can't feel pain. It has no nerve endings of its own. People with red colored hair are 1% of all people. 2% are natural blondes. Yeah, most people you see with these hair colors have dyed hair. Black is the most common hair color in the world. A human eye resembles a car engine. Both of them need liquid for good lubrication. The engine needs oil and the eye needs tears. To make sure the eyes work right, tears are distributed all over them. That's why we blink more than 10,000 times a day. So, let me tell you a tale about tails. There are some cases of humans being born with a tail. There are about 25 confirmed cases known to scientists.

Those born with tails, though, won't have any real benefit other than what the tailbone does for balance anyway.

The tails have no function other than physically being there as they have no bones. The tails only consists of nerves, vessels, and muscles.

Now, do you find that you're a picky eater? Do you think that coriander tastes like soap? Or you can't stand pineapple on pizza? Really? Well, this may be due to what kind of taster you are. Up to 30% of people are considered super tasters and will experience different levels of enjoyment or disappointment from their foods. Food that is bitter to the super taster will likely be sweet to average tasters who make up 40% of people. There are also 30% of people who are non-tasters and won't find anything too exciting. I guess you just have to develop a taste for that. The vast majority of people have brown eyes. About 79% of the world population share this eye color. Once all humans only had the brown pigmentation until around 6 to 10,000 years ago, and I wasn't around then when humans migrated to Northern Europe. A mutation occurred helping the eyes to adapt to the change of light. Blue eyes became the most common of the mutated coloration and all of them today can be traced back to one ancestor from Europe.

His name was Chadwick Abernathy. His friends called him Chad and he was a boulder mover at Stonehenge. Well, not really. Today, blue eyes make up around 10% of the human population. Amber and hazel eyes each take up 5% respectively.

Gray eyes are up to 3% and the rarest of eye colors are green ones consisting of only 2%. Rarer still is heterocchromia iridum where both eyes are of different colors. It's inherited and also affected by other genetic factors. Only 1% of the human population have this incredibly rare attribute. Do you have a small hole in the front of your ear above the ear canal? This is a pre-oricuricular pit.

During the first 6 weeks of a child's development, long before being born, the oracle, which is the external part of your ear, will develop. The preoracle pit forms when the oracle doesn't fully fuse. This occurs in less than 1% of humans. Although there's speculation that having this little hole is the remnant of gills that we once had from our seafaring ancestors, there is nothing solid to confirm this theory.

If you can lick your elbow easily or touch your thumb to your forearm, congratulations. You're among the minority of people. But some people bring flexibility to the next level.

This condition is called hypermobility.

It allows rare individuals to twist their bodies into weird positions just like a snake, putting their head between their feet, doing a back bridge, and all sorts of splits. But in some cases, hypermobility can increase sensitivity because such people have a larger medela. This brain area is responsible for processing emotions. 90% of people are right-handed and only 10% are left-handed. Yes, that adds up. But there's also a very small percentage of those who can use both hands equally well, including writing, drawing, and doing any tasks. Naturally, ambidextrous people account for only 1% of the entire population, which is about 70 million people. If you want to check whether you're one of them, try to write the same phrase with both hands or draw a circle first with your right and then with your left hand. If there's no difference, congrats. By the way, these exercises are very good for balancing the hemispheres of the brain, regardless of which hand is your dominant one. And if you have three hands, well, that's a different video. Your fingernails grow faster on your dominant hand. In other words, if you write with your right hand, it's all right. And you'll have to trim those nails more often. Your fingernails also grow faster in the summer and during the day. Your skeleton will renew itself completely within 10 years, and yes, without surgery. An adult uses around 200 muscles just to make one step. So, don't tell me I don't work out enough. Every minute, your body sheds more than 3,000 skin cells. It's almost 200,000 skin cells per hour and more than 9 lb per year. Hey, it's the shedding skin cells weight loss plan.

Oo, sign up. But hey, don't worry. You still have about 300 million skin cells at any given moment. Plus, your skin completely renews itself every 28 to 30 days. The liver is the only human organ that can regenerate completely. As little as 25% of the original liver weight can get back to its full size. Some people can hear their eyeballs moving inside the eye sockets.

Wow, that must be no fun. Unlike other parts of your body, your ears and nose never stop growing. Wow, that must be no fun.

Your skin wrinkles if you stay in the water for too long, but not because it absorbs water. When your body's wet, wrinkled fingers and toes provide you with a better grip. You know, like when the treads on your car tires grip the road better when they're new. Your eyes are an amazing instrument. They can distinguish between 10 million different colors. Your brain uses more than 20% of your body's energy, even when you're resting. When you're asleep, it still consumes almost as much power as when you're awake. It also burns around 330 calories per day at that. An adult person has about 25% of all their bones in the feet. Most of them are tiny but crucial. If these bones are out of alignment, so is the rest of the body.

You breathe around 20,000 times a day.

I've counted. Try not to stop. I actually set a personal best record today for consecutive days breathing, and I plan to top that tomorrow. Human bones are a real paradise. They're almost five times stronger than a steel bar with the same width, but can fracture on impact and are rather brittle. If a person has asnosmia, also called smell blindness, they can't distinguish and detect smells, but they can still be smelly. Sorry. You start feeling thirsty when water loss is 1% of your body weight. More than 5% and you may faint.

Water loss that's bigger than 10% of the body weight and dehydration can end a person if you know what I mean. The strongest muscle in your body based on its weight is your jaw muscle.

Yes, mine is way overdeveloped. At any moment 50,000 cells in your body are getting replaced by new ones. Boy, that sounds like a company I used to work for. By the end of their life, the average person can recall up to 150 trillion pieces of information, except for where they left their car keys. Even if fingerprints are badly damaged, they still go back with their original pattern. Don't believe me? Hey, give it a whirl. Your brain's memory capacity is equivalent to about 4 tab on a hard drive, which is more than 8 million photos.

People are the only living creatures that can naturally sleep on their backs.

Even apes usually sleep in a sitting position leaning on something. Don't wake them up. Your longest bone is your thigh bone, not your funny bone. And the tiniest one is in the ear. It's shorter than a grain of rice. Do you feel ticklish when you tickle yourself?

Normally, you wouldn't unless someone else tickles you. It happens because the cerebellum area of the brain, which monitors movements, predicts the sensations caused by your own movements.

Then it sends a signal to other parts of the nervous system to cancel these sensations. But some rare individuals can actually feel ticklish on their own.

If you're not among them, touching a new texture that the brain doesn't yet recognize or using a scalp massager can help to excite your nerves and bring relaxation.

Hey, you can give it a tickle test. If you want to check out the work of your vestibular system, try this simple trick. Stand on one foot and close your eyes. Most people lose balance, at least during the first attempt. Your vestibular system includes many organs and systems throughout the body.

Together, they allow your body to stay in balance in different positions. This system includes the inner ear and vision, which is why keeping balance is much easier in silence while your eyes are open. Can you wiggle your ears intentionally? Are you popular at parties for doing that? Congratulations.

Around 22% of people on the earth are capable of wiggling one ear. As for moving both ears at once, only 18% can do that. Air wiggling used to be a common thing for our distant ancestors.

Scientists believe they could perform a variety of movements with their ears.

The group of muscles responsible for wiggling are called the oruriculars.

Mostly don't need it today. But some people claim that everyone can learn to move their ears. It only takes time and practice. Unfortunately, we still cannot acquire this classy habit of twitching an ear toward a sound source as dogs and cats do. Nor can we actually lend an ear to someone. They're challenging to remove and [Music] reattach. We um I mean human beings have been evolving for 6 million years, but we're still not perfect. Turns out that our bodies have a bunch of design flaws. First of all, human eyes have tiny blind spots. Never mind the philosophical ones. Such a spot is about the size of a pin head. It's located at the point where the optic nerve passes through the surface of the retina at the back of the eye.

Your optic nerves connect your eye to the brain. They carry images for your brain to process. This is how you see.

In the spot where these nerves leave your eye, though, there's a lack of something called photo receptors. These receptors detect light and are the reason you can see. Without them, your eyes wouldn't be able to send any signals to your brain to describe what you're looking at. But because there are no photo receptors there, you've got a tiny blind spot in each of your eyes.

If people were designed perfectly without this flaw, they'd have eyes just like octopuses. It may sound weird, but the eyes of these creatures are eerily similar to humans. But their optic nerves run behind the retina. This means that the nerves don't have to leave the eye at any point. So there's no gap that causes the blind spot in human eyes. What else? Around 65 million Americans complain about having issues with their back. And this is because of evolution. Just like dogs, humans used to walk on all fours. When people were walking on their hands and knees, the curve of their spine was pretty much perfect and all their organs felt comfortable. Because of this, there was never any pressure on their backs. Well, we evolved to start walking on two legs to save energy. The search for food took longer and longer. And when walking on two legs, people saved 25% of energy.

But this was bad news for people's backs because this way their spines were basically forced to turn into a column to support all the weight and make space for other organs. But if your spine was completely straight, you wouldn't be able to walk on two legs. So it evolved to become curved. But this puts a big amount of pressure on your lower back.

So basically, to get rid of our pesky back problems, you should start walking on all fours again. That'll work. Make no bones about it. People have too many bones in their feet. We have all these bones because our ape-like ancestors needed them to grab onto tree branches. Now people aren't swinging from trees anymore, but we still have all those bones, which makes us prone to damaging them. And this can be extremely uncomfortable. Think about how many times you've stubbed your toes. If we were designed perfectly, our feet would look like those of an ostrich. These birds have way fewer bones. And the parts that look like knees turned backwards are actually their ankle joints. This makes ostriches less prone to injuries and also helps them run fast. Wow. If people were designed this way, it would make the Olympics way more interesting. I'd sure watch. Now, chew on this one. Human teeth are also far from perfect. People spend so much money on preserving them.

At the same time, no other animal has to visit a dentist as we do. Also, once our teeth are permanently damaged or fall out, we can't grow new ones. Sharks are the opposite. They have an endless supply of teeth. In some shark species, a new set of teeth develops every 2 weeks. Kangaroos also have way better teeth than people do. If we were designed perfectly, we'd probably have the same teeth as our bouncing buddies. Once their teeth wear down, they fall out and their rear teeth migrate forward.

That's not the only issue we have with our teeth. Our mouths are way too crowded. Hey, I normally have a foot in mine. In the process of evolution, the human brain grew dramatically, and our jaws had to become wider and shorter to make room for it. But this left almost no room for our wisdom teeth. In the past, wisdom teeth were helpful when people needed to break down food. But as we learned to cook and process food, these teeth weren't needed anymore. So in short, people should just get rid of them completely. And this may actually be happening. Around 25% of people, mostly Eskimos, are now born without some or all of their four wisdom teeth. Now, it happens that our knees are quite impractical, too. It's the most complex joint in the body. It's sandwiched between two massive levers, which is already pretty risky. The knee only moves forward or backward, which doesn't make it a very secure construction. That's why there's a bunch of rules in many kinds of sports like soccer or rugby that forbid hitting an opponent's knee from the side. To make people better suited to their new sporty lifestyle, the hinge-like mechanism of the knee could be replaced with a ball and socket. This would be like the structure you have in your shoulders and hips. Friends, Romans countrymen waggle your ears. Yep, like dogs and cats, some humans can waggle their ears. These lucky ones can move their ears independently thanks to special muscles called extrinsic ear muscles, but those serve literally no purpose apart from providing a cool party trick. Speaking of design flaws, human voice boxes are in the completely wrong place. Your windpipe, thanks to which you can breathe, and your food pipe, which is, you guessed it, where the food goes, open into the same space. This space extends from your nose and mouth down to your voice box.

You have a little leafshaped flap that covers the opening to your voice box whenever you swallow. It prevents food from going into your windpipe. But this mechanism isn't always fast enough. If you're talking while eating, it's incredibly easy for the food to slip down and accidentally go into your airway, and you definitely don't want that. The whale's voice box is designed much more wisely. It's located in its blow hole away from its mouth. If people could move their voice box into their nose, they would have two separate tubes and there would be no risk of choking. But there would be a downside.

We wouldn't be able to talk. But we could communicate through singing instead like our whale friends. We'd be able to do this by producing vibrations in our noses. Kind of like this. Don't I sound better? Hey, leave me a comment below. You like ribs? I love them. But we're not talking about those kind of ribs. Some of us humans have an extra 13th set of ribs. Between 1 and 3% of the world's population have these ribs called cervical and they serve absolutely no purpose. Some people have just one of such ribs on the left side or the right side of their body and others have cervical ribs on both sides. Now, you don't really need your appendix. It may contain some useful bacteria to help when you have stomach issues, but apart from that, it's not really necessary. The worst thing is that the appendix can get easily inflamed. The appendix was originally designed to help people digest cellulose, which is found in most green plants. This was back when people's diet mainly consisted of plants and almost no animal food. So, I say, let's get rid of it. Moving on. Blood is delivered from your heart to all the tissues of your body through thin pipes called arteries.

The blood flows into each of your arms and legs through one large artery. For your arms, this artery is located at the biceps. And for your legs, it's in the front of the thigh. But your back needs blood, too. And still, instead of having a large artery at the back of your body, you have smaller ones branching out and bundling around your bones and nerves.

This is really impractical and makes people pretty susceptible to glitches, which is why you often get numb arms or legs.

Bummer. How about something humorous?

Take a look at your elbow. There, a branch of the artery meets up with something called the ulnar nerve. Thanks to this, you can move your pinky fingers. This is also why when you bang your funny or humorous bone, your arm goes all numb and tingling.

Ow. To fix this, we really need one more large artery in the back of our body near the shoulder blades. This extra pipe would provide the blood with a more direct route. This would also stop your arms and legs from going numb when you bump them in the wrong place.

Finally, there's this tail. People still have a tailbone even though there's no tail in sight. For our ape-like ancestors, the tail was incredibly helpful. They used it to balance themselves while jumping from one high branch to another. Now that we live in actual houses, most of us don't swing through trees anymore. The tailbone, whose official name is the coxus, is easily fractured. So, currently, it's just a design flaw. Researchers also claimed that removing it would improve posture issues, too. That's it for today. So, hey, if you pacified your curiosity, then give the video a like and share it with your friends. Or if you want more, just click on these videos and stay on the bright