Actually, as an amusing bit of trivia, there is an Indian (Native American) tribe that due to some wonky genetics actually has no nipples. They relied on domesticated animals to provide milk for their children. But throughout the centuries their numbers have dwindled, so now only about 500 of them survive.
Among anthropologists, they're called the Indian-nippleless 500.
Wow....how have I lived in Indiana all my life and NEVER heard this one before???