Two types of ancient human ancestors coexisted more than 2 million years ago, fossils show

Fossilized teeth show that two different kinds of ancient human ancestors coexisted more than 2 million years ago. One of them may be an unknown species.

​ Fossilized teeth show that two different kinds of ancient human ancestors coexisted more than 2 million years ago. One of them may be an unknown species. Read More Breaking News, Latest News and Videos | CNN