Primate Pharmaceuticals, Mouse First Aid and Ant Amputations: Non-Humans Using Medical Care

You might expect a hurt animal to retreat and lick their wounds, but some creatures have a more advanced approach to treating injuries. Here are several examples of non-humans using medical care, including how...

• Chimpanzees, orangutans and bonobos treat ailments using plants
• Mice give first aid to unconscious friends
• Florida carpenter ants perform life-saving amputations

Chimpanzees, Orangutans and Bonobos Treat Ailments Using Plants: Picture an old man collecting local leaves, grinding them into an ointment and applying them to sore joints. Now imagine that figure is actually an old man of the forest, an orangutan.

The great apes are our closest relatives and their use of simple tools is well documented, but recent observations suggest our cousins can also prepare and apply medicine. Scientists observing orangutans in Borneo noticed that they would chew leaves from Cantley's dracaena until they formed a soapy lather, applying the resulting paste like an ointment. The plant is an anti-inflammatory, meaning that it would offer relief to a sore limb - in fact, the local humans use dracaena poultices to counter aches. The researchers also noted that adult females made up the majority of the ointment users - perhaps the paste is being used to treat muscle pain from carrying a baby through the trees?

Orangutans are not the only apes to turn to pharmacology. Wild chimpanzees in Uganda have been observed eating nutritionally poor plants (ones that were not normally part of their diet) when sick or injured. Researchers followed them and tested those plants, finding that 88% possessed anti-bacterial properties and 33% were anti-inflammatory.

One chimp with a hurt hand sought out and ate the leaves of a fern with powerful anti-inflammatory effects that may have reduced the pain and swelling of the injury. Curiously, some of the plants are already used by the local human population as folk remedies for similar complaints.

As well as chimpanzees, bonobos have been recorded consuming spurge leaves without chewing them. Researchers who dug through fecal matter found that the leaves had not been broken down, which means that they were not being eaten for nutrition. Instead, scientists believe that the plant may promote gut motility and be used in response to bloating and internal discomfort.

Chimpanzees have also been observed treating each other's wounds, including applying chewed plant material to injuries. Licking wounds, dabbing wounds with leaves and the aforementioned application of chewed medicinal plants have all been recorded. Researchers even managed to film a young chimpanzee treating a wound on her mother with chewed herbs. This behavior wasn't limited to family - on several occasions the chimpanzees treated unrelated individuals, suggesting a level of altruism or empathy!

Mice Give First Aid to Unconscious Friends: The typical human response to an unconscious person is an attempt to revive them - usually by calling to them or shaking them if this doesn't provoke a response. It seems that this may not be a purely human trait though, as scientists recently found that mice seem to do the same kind of thing!

Researchers anesthetized mice and observed how "social partners" (mice familiar with the unconscious rodent) reacted. The mice displayed a consistent set of behavior - starting with sniffing and grooming then progressing to biting the mouth or pulling on the tongue. It's worth noting that these actions could help clear or broaden the airways of the unconscious mouse to help them recover... and that these actions ceased if the mouse began to regain consciousness.

The mice behaved in the same way when confronted with a freshly-deceased social partner but not a sleeping one, suggesting they were able to tell that something was wrong. They also were much less likely to perform these actions on an unfamiliar mouse!

Florida Carpenter Ants Perform Life-Saving Amputations: So far we've seen the preparation of medicine and attempts at resuscitation... but did you know that there are ants that perform amputations?

Many ants treat an injured comrade by coating their wounds in a mixture of antimicrobial goop (after all, scuttling across the ground with a large open wound is just asking for an infection) but the Florida carpenter ant doesn't have the glands responsible for this sterilizing fluid When a comrade has a wounded leg, the carpenters will make a judgment call over whether to clean it... or to amputate.

The amputations seem limited to femur (thigh) injuries. Researchers found that an ant with a wound in this area would be cleaned by a nestmate and then have the limb chewed off. The treatment seems effective - ants who received an amputation survived around 90% of the time, while ants who didn't receive amputation had a less than 40% survival rate.

The ants didn't attempt to amputate tibia (shin) injuries, instead attempting to remove dirt from the wound. Survival rate here was around 75%, dropping to around 15% if other ants were not present to clean the injury.

Researchers believe that the ant femur contains a great deal of muscle responsible for pumping hemolymph (insect blood.) Damage to those muscles from a wound probably slows the rate at which infected "blood" is able to leave the limb, so a swift amputation could stop the spread. A wound to the tibia would not affect these muscles, meaning infection could quickly circulate into the body of the ant and render amputation pointless.

Sources and Further Information:

Self-medication by orang-utans (Pongo pygmaeus) using bioactive properties of Dracaena cantleyi

Study shows wild chimpanzees seek out medicinal plants to treat illness and injuries

New Evidence for Self‐Medication in Bonobos: Manniophyton fulvum Leaf‐ and Stemstrip‐Swallowing From LuiKotale, Salonga National Park, DR Congo

Chimpanzees use medicinal leaves to perform first aid

Wild chimpanzees filmed using forest 'first aid'

Reviving-like prosocial behavior in response to unconscious or dead conspecifics in rodents

Wound-dependent leg amputations to combat infections in an ant society