The Spider That Pretends to Be Bird Droppings

The Disguise No One Wants to Touch

In nature, camouflage can be beautiful — like butterflies with leaf-shaped wings or stick insects that vanish among twigs. But not all disguises are about elegance. Some creatures choose something far more effective: disgust.

Meet Celaenia excavata, better known as the bird-dropping spider. Native to Australia and New Zealand, this spider doesn’t try to blend in with flowers or trees. Instead, it mimics bird poop — in color, shape, and even shine.

It’s one of the most effective and ridiculous survival strategies in the animal kingdom. And it works.

What Is a Bird-Dropping Spider?

Celaenia excavata is a member of the orb-weaver spider family, but it behaves quite differently from the spiders that build large circular webs. It’s a nocturnal ambush predator that spends most of its time sitting still — often on a leaf, branch, or fence post — disguised as something every predator avoids: a fresh splatter of bird droppings.

Its coloration is splotchy, with shades of white, brown, and grey. The body is lumpy and uneven, shaped like a dripping blob. And when it curls up during the day, it adds to the illusion by remaining motionless in a messy pose.

Even its glossy surface reflects light, creating the wet, shiny effect of fresh bird poop.

To the casual eye — or a hungry bird flying above — it looks exactly like something no one would ever want to eat.

Why Mimic Poop? Because It Works

Predators like birds, lizards, and larger insects rely heavily on their vision to spot prey. They look for shapes and movements that resemble food — like twitching legs, shiny wings, or soft bodies.

By disguising itself as something disgusting, Celaenia excavata becomes invisible in plain sight. No bird wants to taste poop. No predator will waste time with something that might be inedible — or worse, diseased.

And that’s exactly what this spider is counting on.

It doesn’t need to run. It doesn’t even need to spin a big web. It just sits and waits.

A Hunter That Uses Scent Instead of Webs

At night, the bird-dropping spider shows its true nature — as a cunning predator.

It doesn’t use a web to trap insects. Instead, the female releases pheromones that mimic the scent of female moths, attracting unsuspecting male moths straight to her hiding spot.

The moth, believing it’s about to meet a mate, follows the scent… only to land directly on the spider.

Without hesitation, she strikes, injects venom, and begins feeding.

This chemical deception makes Celaenia excavata not only a master of disguise but also a manipulator of other species' communication systems — a rare and complex strategy in the spider world.

The Females Are the Stars

Like many spiders, there’s a huge size difference between males and females. The female bird-dropping spider can grow up to 1.5 cm, while the male is barely 2–3 mm.

The males don’t mimic poop and don’t hunt in the same way. They spend most of their time wandering in search of females to mate with — often becoming prey themselves in the process.

It’s the females who own the disguise, the hunting tricks, and the ability to lure and kill.

Egg Sacs That Look Like Seeds

Even the next generation of this spider is hidden in plain sight.

The female lays her eggs in egg sacs that resemble small brown seeds or galls — another form of mimicry that protects the offspring from being eaten. These sacs are often attached to leaves or branches, blending into the environment just like the mother does.

It’s a full-circle strategy: from the mother’s body to her eggs, every stage is designed for survival through deception.

Safe for Humans, Scary Only to Insects

Despite its creepy appearance and hunting skills, the bird-dropping spider is harmless to humans. It doesn’t bite unless threatened, and even then, its venom isn’t dangerous.

People who spot them in gardens or on fences often don’t realize what they’re seeing — mistaking them for actual droppings. Only when the spider moves or unfolds does the illusion break.

In some cases, photographers and naturalists even wait for rain — because a real bird dropping will wash away, but the spider remains completely still.

Conclusion – Gross, Clever, and Perfectly Camouflaged

While many animals try to look like something beautiful or powerful, the bird-dropping spider proves that disgust can be just as effective.

By choosing the one disguise that predators instinctively avoid, Celaenia excavata survives without speed, venomous fangs, or elaborate webs. It sits, it waits, and it lures — all while looking like the last thing anyone would want to touch.

It’s weird. It’s brilliant. And it’s a perfect example of how nature sometimes rewards the grossest ideas with the greatest success.