In a creative use of insect genetics to solve an enduring mystery of human evolution, scientists studying the DNA of lice have concluded that early humans may have started wearing clothes just a few tens of thousands of years ago, more recently than many had presumed.

The new work — based on subtle genetic differences between human body lice, which depend on clothing for their survival, and human head lice, which do not — suggests early humans may have lived in Europe for tens of thousands of years after leaving Africa before availing themselves of clothes.

Among the work’s controversial implications: Early humans such as Neanderthals — which lived from about 150,000 years ago until 30,000 years ago and which are typically depicted as hairless and clad in furs — may in fact have been quite furry until surprisingly late in their evolution.

“If you look at how Neanderthals are routinely depicted in books and museums, people have just thought they must have had clothing to protect against cold weather,” said study leader Mark Stoneking of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “But if you ask, ‘What’s the evidence?’ it’s just not compelling that they had clothes. Perhaps they had more body hair than we thought.”

The transition from hairy to hairless, and the related advance from naked to clothed, were seminal events in human biological and cultural evolution. But scientists know little about the timing of either.

Anthropologists are especially interested in knowing when people graduated from crude, animal-skin togas to sewn, tailored and decorated clothing — a major cultural advance that offered new ways to broadcast information about tribe, social status or fertility.

“In terms of warmth, you can wrap yourself in a hide, for god’s sake,” said Olga Soffer, an archaeologist at the University of Illinois. “But clothes let you really make much more complex statements. The body is turned into a stage to play all of the kinds of social games you can invent.”

DNA clues

Scientists studying early human culture are increasingly turning to genetic techniques — either studies of ancient human DNA or the DNA of plants and animals that coexisted with early humans — to get around the lack of traditional archaeological evidence. But there is little consensus on how to interpret the first rounds of results.

Long-lasting lice

The new work, published in today’s issue of the journal Current Biology, focused on parasitic lice — highly successful insects that don’t merely hatch but literally blast out of their eggs after pumping them overly full of air — and then live out their bloodthirsty lives biting, chewing or piercing their hosts.

Individual species of lice are intensely specialized, largely to avoid grooming and preening behaviors by creatures trying to get rid of them.

Stoneking took advantage of a specialization that separates two species of human lice. Head lice stay on the head and glue their eggs to the shafts of hairs (with a cement that dries so hard and so fast that the female sometimes gets fatally stuck there by mistake). Body lice feed on hairless parts of the body and lay their eggs only in clothing, especially in protected areas such as seams.

By figuring out when body lice first appeared, the team reckoned, they’d get a good idea of when clothing arose. “It’s possible that clothing may have existed for some time before body lice,” Stoneking said. “But in general … when a new ecological niche becomes available, organisms move in very quickly.”