Some insects mimic dung. Ever since Darwin, biologists have explained this as a form of camouflage: selection favors individuals who most resemble dung because they are less likely to be eaten. Some have questioned how this could have evolved. In the words of one eminent scholar: ""Can there be any edge to looking 5% like a turd?"" Why might looking 5% like a turd provide a selective advantage than not looking like a turd at all?

If a bug looked 95% like a bug and 5% like, it would have a small advantage over the other bugs who didn't look like . However, there are many other factors to this. Say a bird or owl was flying through the air looking for bugs to eat. In addition to the bug looking like compared to the other bugs, there is also a fair amount of things that are blocking the birds information on where it is looking. There are trees in the way, branches, leafs, bushes, shadow, light and etc. Not to mention the bird is traveling at a fast rate. When the bird spots the bug that looks like , even though it only looks 5% like , it must make a split second decision on whether or not it's looking at food or as all of the previous factors obscure it's way of processing information.

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