Humans and mammals

why do Humans and mammals have white skin, yet no black skinned mammals only Gorillas.

All cats and dogs have white skin, so this can't be a mutation, and shows that Africans are not related, to all other humans are mammals.

That is because fur protects animals from sun. And clothes protect white people. All while black people evolving in the warm climate don't need to wear fur during day.

Black people also get nasty diseases in colder climate. That is why American Blacks slowly become white. Those having darker skin produce less kids.