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

Melanin required resources to produce, and also does sloghtly reduce vitamin D production so in areas with less light, it was better to have less melanin and maximize vitamin D production. At higher latitudes, UV damage isn’t as much of a worry.

BUT this particular hypothesis on why skin color changes around the world is not definitive despite how popular the idea is. There are likely other interacting factors we haven’t worked out yet.