Sea otters spend most of their lives in water that can be as cold as 0°C (32°F). Many marine mammals have blubber, a thick layer of fat, to keep them warm. But sea otters don’t have blubber. So how do they stay warm?
In the past, scientists had only known about one feature that helps keep otters toasty—their thick waterproof fur. Recently, researchers discovered that sea otters also stay warm thanks to their cells, the basic units of life. Mitochondria are the energy-producing parts of a cell. The mitochondria in sea otters’ muscle cells leak out excess energy in the form of heat, keeping the animals warm.
Other marine mammals may keep warm in this way too, explains Terrie Williams. She studies how an animal’s anatomy interacts with its environment. “This could be a game changer!” says Williams.