Sometimes I learn something that makes me say, "Holy shit, that's interesting!" One such thing happened today, so I took to the Internet and decided to shout impotently at the masses in the hopes that someone else will be similarly impressed by the shit.
So, holy shit, scientists can use lice to determine when humans started wearing clothing. I've been lucky enough to only personally know lice as a mysterious head-related ailment that made me leave class in elementary school once in a while to have my head fondled by a nurse. As it turns out, head lice can only live on human scalps and subsist entirely on human blood. They can't exist without us.
Body lice are the same way, but even more interesting. They live exclusively in human clothing. Their evolution was based on a synthetic factor, which in itself deserves a fresh "Holy shit!" Using what they call "molecular-clock dating," biologists are able to estimate the origin of body lice at about 107,000 years ago. That's apparently right around the time certain packs of humans decided that Africa was too goddamn hot and started colonizing the rest of the globe. They may have tried before, but guess what they had this time to keep them from freezing to death?
And body lice.