Sarah Kuta in Smithsonian Magazine:
The follicles at the root of each hair contain stem cells, which, in addition to producing hair, can grow new skin when necessary. Since humans have much less hair than other mammals do, it makes sense that our wounds would also take longer to heal.
“When the epidermis is wounded, as in most kinds of scratches and scrapes, it’s really the hair-follicle stem cells that do the repair,” says Elaine Fuchs, a biologist at Rockefeller University who was not involved with the research, to the New York Times’ Elizabeth Preston.
At some point in the evolutionary journey, humans lost most of their body hair. Since chimps’ wounds heal faster than ours, this shift likely occurred after humans diverged from our shared ancestor with the primates, reports New Scientist’s Chris Simms.
It’s not entirely clear why early humans lost their hair. But it seems our species swapped the once-abundant hair follicles for sweat glands, which are not as efficient at healing wounds but help keep us cool in hot environments.
More here.
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