This story appears in the March 2017 issue of National Geographic magazine.
Lice have plagued humankind throughout history. Spreading from person to person by close contact, they latch onto hair with hooklike claws and pierce the scalp to suck up a meal of blood. The result is often a very itchy head. Relief comes only with the removal of all traces of infestation—the insects, each about the size of a sesame seed, and the tiny eggs they lay, known as nits.
Picking off the parasites one by one is tedious, so many cultures have crafted fine-tooth combs to hasten the job. Combs of wood, bone, and ivory have turned up at ancient sites in the Old World, but solid evidence for such tools in the Americas was lacking until a recent study in northern Chile.
That research focused on a museum collection of double-sided combs made from common reeds. All came from cultural groups that flourished in river valleys in the Atacama Desert between about A.D. 500 and 1500.
Experts previously suggested that such combs had been used to create complex hair styles. Also, since most of the combs were found in the graves of women, they might have served a function in the female task of weaving.
But viewing the combs at 10 times normal size revealed their true purpose: Many still bore traces of the lice and nits they had extracted from someone’s tresses. In pre-Columbian times, as today, people apparently resisted cutting off all the hair, the easiest way to get rid of lice. “Vanity is stronger than itching,” says lead scientist Bernardo Arriaza. “People prefer to feel ‘lousy’ than bald.”