The surprising evolution of the weirdest animals on Earth, according to a new study

A new study suggests the platypus and echidna — the only egg-laying mammals — had a water-dwelling ancestor. The finding could upend what’s known of their evolution.

​ A new study suggests the platypus and echidna — the only egg-laying mammals — had a water-dwelling ancestor. The finding could upend what’s known of their evolution. Read More Breaking News, Latest News and Videos | CNN