Animals do it doesn't sound like a good reason to me. There is plenty of things humans do and animals don't and vice versa and it's perfectly fine.

The other critters, in general, evolved where they are found.

Humans live in all kinds of environments that are far removed from the East African Rift.

Lots of animals manage by either migrating to the tropics or hibernating through the winter. Neither is viable for a modern human society.