eli5: If more melanin is advantageous in warm climates, why is less of it advantageous in colder climates? Wouldn’t darker skin still be most advantageous in cold climates where it might occasionally be hot?

Question

eli5: If more melanin is advantageous in warm climates, why is less of it advantageous in colder climates? Wouldn’t darker skin still be most advantageous in cold climates where it might occasionally be hot?

In: 1641

Answer 1

As others have already said it is not about heat but sunshine and getting enough vitamin D

Dark skin was an evolutionary adaption to losing most of our body hair and having our skin constantly exposed to the sun.

Millions of years later some of us went out of Africa and started to have problems, then some of those people gave birth to some mutant with less dark skin, who didn’t have the same problems.