Fossil Evidence Reveals Whale Ancestor

Whales and dolphins breathe air and give birth to live young, just as other mammals including humans. But they live out their lives in the oceans. How did land-dwelling animals return to the sea? According to recent research, the evidence is in the skull and ears of a 50 million-year-old fossil.

Raoellids, like the Indohyus depicted in the illustration lived on land eating mostly plants. But examination of their skull and ear bones shows striking similarities to whale anatomy. Further, Isotopic evidence suggests these creatures took to the water often, possibly in search of prey.

Source: Nature.com

Illustration by Carl Buell