Louse specialists now seem at last to have solved the question of how people came by their superabundance of fellow travelers. And in doing so they have shed light on the two major turning points in the history of fashion: when people lost their body hair, and when they first made clothing.
Three kinds of louse call Homo sapiens their home, but each occupies a different niche on the human body. The head louse, Pediculus humanus, lives in the forest of fine hairs on the scalp. Its cousin, the body louse, lives not on the skin but in clothes. And the exclusive territory of the pubic louse, Phthirus pubis, is the coarser hairs of the crotch.
Lice are intimately adapted to their hosts and cannot long survive away from the body's blood and warmth. If their host evolves into two species, the lice will do likewise. So biologists have long been puzzled over the fact that the human head louse is a sister species to the chimpanzee louse, but the pubic louse is closely related to the gorilla louse.
Apes, lice and prehistory(or 'family heirlooms', and 'new aquisitions'):
Human DNA might show 98% similarity to that of chimps, but we share less than 50% of our microbes and parasites with them. Ashford  argues that the great apes became more specialized forest dwellers at the same time that early hominids explored the savannah, and that human gut parasites resemble those of omnivorous baboons more than those of chimps because humans, like baboons but unlike chimps, are omnivorous. Further opportunities for horizontal crossover of microbes and parasites from animals to humans arose when humans spread out of Africa. When we domesticated ruminants, and animals such as dogs, cats and rats 'domesticated' us for the rich pickings around human habitation, we acquired many infections from our new neighbors [5,7]. Thus a shared habitat, rather than a shared ancestry, is important for the acquisition of many infections.
« Older Abortion Drugs Given in Iowa via Video Link.... | How Battle.Net 2.0 is killing ... Newer »
This thread has been archived and is closed to new comments
Buy a Shirt