Life
I'm fascinated by the history of medicine — particularly when it gets gory, gross and preferably involves random animal parts. Everything from ground-up vulture brains up the nose (a medieval European cure for migraine) to wolf's testicles in oil (an Occitan idea for a woman who had "too much desire", to be rubbed on her genitals) pops up if you delve deep enough, and the weirder and more faintly confusing the better. However, modern medicine, with all its wonders, occasionally delivers the sorts of potential cures that may not have looked out of place in a 14th century medical manual. Fish venom to help the immune system? Crab blood to stop the progression of disease? Come off it.
As those previous (and, might I add, discredited) cures attest, we've often looked to the animal kingdom to help us out with our human medical needs, and in some cases it seems as if that was a good idea. Not only that, scientists are increasingly looking to the least benign animals, those in possession of venoms and toxins any sensible person would avoid like the plague, to give us clues about pain relief, the immune system, and other aspects of human health. Nobody said working at the forefront of science was boring.