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If you're a small animal, one of your biggest challenges in life is making sure that you don't get eaten. And there are all sorts of ways of doing this— like, being toxic, or blending in with your surroundings.

Some species even disguise themselves as unpalatable things, like twigs and stones. That way, they can hide in plain sight. But why stop there?

The five species we're going to talk about today take this kind of masquerade to a whole new level of icky. Instead of plants or rocks, they disguise themselves as poop. And not just any poop.

Bird poop. That may be because bird droppings are a bit different from mammal feces. You see, unlike mammals, birds don't produce urine.

They can't afford the water weight. So instead of pee, they excrete noxious ammonia-containing compounds alongide their feces —that's why bird droppings have that pasty white part. And it's possible these additional unpleasant chemicals make their poop that much more repulsive—which, in turn, makes masquerading as bird poop that much more effective as a defense.

Or, it may simply be that bird poop is more common on leaves and other, higher-up surfaces where small, edible animals often want to hang out. Either way, the five creatures on this list show that in a dog-eat-dog world, looking like poop is a great way to stay off the menu. The name “potter wasp” comes from the pot-shaped nests most species in this group of hymenopterans make.

But of the thousands of potter wasp species out there, one from Brazil—Minixi suffusum—builds nests that look like bird poop instead. It might seem surprising that these wasps would need to go to such lengths to stay safe when they're pretty hardcore to begin with. They are wasps, after all, so they're armed with a painful sting.

And when it's baby time, a female potter wasp lovingly deposits a single egg into each chamber of her nest along with a paralyzed but definitely still alive caterpillar, which the soon-to-hatch larva will feed on until it's ready to emerge. But those baby wasps are pretty defenseless. And there are plenty of predators, like ants and other wasps, that would love to make a snack out of them.

Which is why many species of potter wasp disguise their nests in some manner. And it's probably why M. suffusum's nests are splotched white and brown —so they strongly resemble bird poop. When researchers first noticed this, though, they weren't sure what the white part actually was.

So, they watched the wasps build their nests to find out. And it turns out that after a female seals in each of her eggs with their caterpillar meals, she goes out and collects bird poop. So the white stains on these nests are literally the white part of fresh droppings.

I mean, I guess it makes sense. The best way to look like bird poop is to be bird poop. But that may not be the only reason they plaster this stuff onto their nests.

Some researchers think that the additional layer of mud mixed with the white paste could increase the structural integrity of the nest or even help keep the nest cooler by reflecting more light. Now, many orb-weaver spiders make large webs —you know, those big, nearly-invisible bug traps you don't see until you've already walked into them. But Cyclosa ginnaga orb-weavers from tropical forests in East Asia make at least part of their web really obvious.

The juvenile spiders weave a white, irregularly-shaped web decoration on the spot where they hang out when they're waiting for a meal to stick. And since these spiders have small brown and white bodies, together, the web and spider look pretty convincingly like a splat of bird poop. At least, to humans.

But scientists wondered if the strange web spots were really effective against the spiders' main predators: wasps. So, they measured the light that reflected off of bird droppings, web decorations, and the spiders themselves. And since bees and wasps are closely related, researchers used previous research on bee vision to build models of what wasps likely see.

And based on all that, the team concluded that wasps probably can't distinguish between actual bird poop and the spiders on their fancy webs. But that was still not confirmation that the decorations deter hungry wasps. So, the scientists dusted some of the web decorations with black powder —essentially removing the spiders' ability to masquerade.

And when they did that, the spiders were attacked about 4 times as often. Of course we'll probably never be able to tell exactly what wasps are thinking—so we don't know if the spiders really look like bird poop to them. But one way or another, those web decorations do seem to throw them off —and therefore, protect the spiders.

Now, butterflies and moths are often beautiful, delicate creatures. But some have distinctly less attractive origins. The caterpillars of several species are mottled brown and white —presumably, to look like bird poop.

And some caterpillars in Japan take this masquerade one step further. They aren't just colored like droppings. They also seem to modify their behavior to pull off the ruse.

See, some scientists noticed that these caterpillars curl themselves up when they're resting. And that shape was more poop-y looking to them. But they weren't sure if the caterpillar's primary predators (birds) would agree.

So the researchers made models of fake caterpillars. They were either green or brown and white, and had straight or curled-up postures. They then put hundreds of these four different models in cherry trees all over Tokyo and observed what happened to them.

It turned out that the combination of color and posture did matter. Both of the green caterpillar models were attacked by birds about 20% of the time. But curled-up brown and white caterpillars were attacked about half as often!

Now, it's not really surprising that there are multiple spiders on this list. After all, over one thousand species of spider are thought to masquerade as some sort of object. So the idea that there's more than one that pretends to be bird poop isn't all that unexpected.

But the appropriately-named bird-dung crab spiders from Southeast Asia and Australia are probably the most convincing. Their mottled brown coloring—and lumpy and glossy texture— help them look like fresh feces. And though they don't make a classic web, they may weave a whitish blob of silk on a leaf to rest on, adding to the illusion.

But what really allows them to steal the show is that they don't stop with visual cues. These spiders also produce chemicals that make them smell like poop. Now, it's not totally clear which compounds give the spiders that Eau de Excréments—but according to researchers, it's quite a pungent scent.

And though there's not a ton of work on this, preliminary research suggests the smell alone can put off potential predators. It might even do more for the spiders. Although this has yet to be confirmed in follow up studies, preliminary results indicate that these foul-smelling chemicals may help attract prey, as well!

Because not everything avoids poop. Many flies absolutely love the stuff! So far, we've seen animals that look like poop, smell like poop, and even act like poop.

But the moth Macrocilix maia is a true fecal artist. Instead of merely masquerading as bird poop, it seems to have an entire poop tableau painted across its wings. See, when they're unfolded, the wings seem to depict two flies feeding on poop.

The “flies” have grey and black bodies and red heads— just like some species of muscomorph flies that live in the same area and have been known to feed on feces. Plus, each has a patch of white which might be mimicking the light that a real fly's wings would reflect. Then, in between their heads is a brownish, mottled section that sure looks a lot like a splat of bird poop.

And photographers have reported that these moths smell like bird droppings, which would make the illusion even more convincing. But, it's not totally certain that this scene is what the moth is going for. This species lives in tropical Asia and very little is known about it.

Almost no formal research has been performed on them. And the potential advantage of having a mural on its wings is also a mystery. There are lots of things that eat flies which also might enjoy eating a moth – so why look like flies and poop rather than just poop?

I guess we're just going to have to wait for someone to conduct some more research on this amazing animal to find out. But that amazing moth is hardly the only potential mimic in need of further study. Like, the frog Theloderma asperum is sometimes called the bird poop frog—but it's unclear if this is a true masquerade, or if the coloring simply helps the frog blend in with the brown, bumpy tree bark where it lives.

The lack of research into bird poop mimics is actually why this list isn't a lot longer. There are a shocking number of creatures that seem to look like droppings. But only a few have been studied formally to show that other species are actually deterred by their behaviors, colors, shapes, and/or smells.

So I guess what I'm saying is that if you're looking for a research project, there are a lot of fecal fakes out there just waiting for someone to prove that they're convincing. Thank you for watching this episode of SciShow! We hope you enjoyed learning about these unsavory characters.

Let us know which was your favorite in the comments! And if you thought these mimics were wild, you'll probably love our episode on ant mimics. I mean who knew there were so many things that dress up as ants?

I guess Entomologists? I don't know. You should check it out! [OUTRO ♫].