The Sea Otter (Enhydra lutris) is the smallest marine mammal in North America – males measure 1.2 metres in length and weigh an average of 45 kilograms (females are a bit smaller). At the same time, the Sea Otter is the largest member of its family, the mustelids, which includes River Otters, weasels, badgers, wolverines and martens. It’s also the only member of its family that doesn’t need land at all; it’s completely adapted to life in the water. It may come to land to flee from predators if needed, but the rest of its time is spent in the ocean.
The Sea Otter’s fur is one of the thickest in the animal kingdom, with 150,000 or more hairs per square centimetre. It varies in colour from rust to black. Unlike seals and sea lions, the Sea Otter has little body fat to help it survive in the cold ocean water. Instead, it has both guard hairs and a warm undercoat that trap bubbles of air to help insulate it. The otter is often seen at the surface grooming; in fact, it is pushing air to the roots of its fur.