Prehistory and the DNA of Lice
Anthropologists think they know when humans started wearing clothes. How could they possibly know that, you might ask, when clothes don’t fossilize? After all, we’re talking about a period before written records or even cave paintings. The answer comes from the genes of lice.
Body lice belong to the same species as head lice, but they have their own subspecies. They’re Pediculus humanus corporis, while head lice are Pediculus humanus capitis. Body lice have claws adapted to grasping fabric and other materials, rather than hair, and they secure their eggs to clothing. So they need clothes and can’t have evolved from head lice until our ancestors got dressed. Scientists think the bloodsuckers would’ve exploited the new environment pretty quickly after it appeared, so body lice must have split off from head lice around the time clothes came along. Genetic analysis can tell us when two species diverged: when their last common ancestor lived. The answer from studies of Pediculus humanus DNA? Lice split into two subspecies—and people started wearing cloths—sometime between 80,000 and 170,000 years ago.
Interestingly, the Homo sapiens who lived eighty-plus thousand years ago weren’t quite … us. They’re called “anatomically modern humans” because their bodies matched ours (roughly), but their brains apparently didn’t. Anthropologists think they lacked real language. In other words, our ancestors started getting dressed before they could talk.
© 2013 by David Carthage.