Why Aren’t (Most) Humans Furry?

Ever since Darwin first made headlines, scientists have been pondering why humans lost their natural coats as they evolved from apes. The theories range from lice to cannibalism.

The traditional theory—refined by scientists over the past 40 years—proposes that humans gradually became furless in order to withstand the brutal heat of the African savanna or to prevent over heating while chasing prey. One alternative idea, put forth in 2003 by evolutionary biologist Mark Pagel of the University of Reading in England, is that as humans learned to keep warm by making clothing and building shelters, they no longer needed heavy body hair. This hairlessness prevented parasites, such as mites and ticks, from sticking to their bodies. Avoiding parasites led to healthier humans, Pagel posits, and because there’s nothing as attractive as a bug-free hominid, hairlessness became a desirable feature in a mate, and natural selection drove the hairier folks into extinction.

In 2006, developmental psychologist Judith Rich Harris suggested a far more gruesome mechanism. As humans became hairless as a result of chance mutations, they split geographically from their hairy cousins. Once hairlessness was in style, any hirsute baby born to a hairless tribe was abandoned. As hairlessness became the norm, a thick fur coat would have become so rare that hairy humans would have been seen as animals and hunted for food. The days before waxing were savage indeed.

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What Causes Volcanic Lightning?

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