Inner Ear Facilitated Cetaceans’ Agility

Whales originated from land animals that looked like pigs, but changes in their inner ear helped them evolve into acrobatic swimmers, British scientists reported in the May 9 issue of Nature. By studying fossils of whales, the team uncovered clues about the evolution of cetaceans--whales, dolphins and porpoises--and how and when they became such agile sea creatures.

Whales left land permanently about 45 million years ago. Whales and other cetaceans have a unique sense of balance because the semicircular canals in their inner ears, which sense head movement, are much smaller for their body size than those of other mammals.