Why Are Black People Black-Skinned?

While asking the question ‘Why are White People White?’ (here), I touched on that black people are black by the same mechanism. However, my explanation was too brief, and the question deserves its own full answer. Keep in mind this evolutionary cheat-sheet: first, there was panting and hairiness, and then came limited sweating and hairiness, and now we have full-body sweating and no hair (little hair).

To begin, earlier hairy primates, or proto-humans, living in Africa were less efficient at dissipating the body heat that resulted from strenuous exertion (hunting, gathering, and avoiding predators). Panting is the way most mammals cool themselves, rather than through sweating. As an evolutionary alternative, sweat glands appeared first over hairy bodies and then over less-hairy bodies, allowing for rapid cooling and quick evaporation. Evaporative cooling pulls heat away, countering the insulating effect, whereby the moisture stays on the skin, trapped by hair, and increasing in temperature from both the sun and internal exertion.

Indeed, sweat glands were an improvement over panting, allowing for greater exertion, but there was another hurdle. Full-body hair on proto humans grew out of ‘white (non-pigmented) skin’ underneath, in combination to regulate Vitamin D(3) production, for bone and reproductive health. Without the hair to block the sun, the skin had to take on this critical task by itself, via melanin production, thereby making the evolutionary case from fully covered, dark haired, white-skinned, proto-humans into hair-less dark-skinned humanoid descendants. Viola, black people!

It was relentless large brain demands (thinking) of proto-humans that drove body evolution to change and advance. Hairlessness, sweat glands, and dark-skin proved a potent combination in response, allowing humans to run greater distances, fight longer fights, dehydrate at a slower pace, and recover normal body temperature more quickly. Humanoids quickly became formidable foes, as their body capabilities ‘caught up to’ their brainy demands.

Reference: Nina Jablonski, PhD., "Skin:A Natural History".

James C. Collier

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