Politically incorrect Q: If different racial charactistics evolved as response to different climates, why aren't Alaskan natives or oriental peoples from the north or indigineous peoples of Australia and South Africa as pale as northern Europeans?
According to this article, it has to do with dietary differences. People with diets high in vitamin D don’t need the sun to help them synthesize it. That’s the explanation offered for the Inuit, at least. I don’t know how broadly it might apply.