Biologists recently discovered skin proteins shared by humans and turtles which developed in a common ancestor roughly 310 million years ago.
While evolving with specialized defenses has helped animals escape predation, long-term risks need to be considered. The simple act of camouflage or mimicry, which sufficiently confuses prey, doesn't seem to have backfired, but the use of chemical defenses has. In fact, some amphibians that release lethal toxins to kill predators are now at a higher risk of extinction.
For as long as experts have been researching how bats hunt, they have also seen that some moths have the unique ability to jam honing sonar. Among hawkmoths, for instance, the sonic calls of bats are apparently disrupted by dissonant signals coming from the insects' genitals. Now, researchers think they have determined the evolutionary roots of this unusual defensive adaptation.
When you think of beetles, you probably think of the many harmless bugs that wing around a garden looking for some tasty aphids to devour. They don't bother you, and you likely have no reason to bother them. This changes in the case of the bombardier beetle - a species infamous for its ability to spray a powerful jet of superheated chemicals that can even scald human skin.