Sea otter grooming fur, Monterey Bay, California, United States

Sea otter grooming fur, Monterey Bay, California, United States

Few animals are as closely tied to the health of coastal ecosystems as the sea otter. In today's image, one grooms its fur in Monterey Bay, California, USA. This behaviour is far more than a daily ritual. Unlike seals and whales, sea otters have little insulating blubber, so they rely on the densest fur of any animal. Careful cleaning traps air within their coat, creating a waterproof layer that helps them stay warm in the cold Pacific.

Sea otters are also considered a keystone species. By feeding on sea urchins and other invertebrates, they help control populations that can otherwise overgraze kelp forests. Their foraging habits are equally fascinating: they are among the few marine mammals known to use tools, often cracking open shellfish with stones. When resting, they may wrap themselves in kelp to avoid drifting away, while mothers keep pups close on their chests as they float. Protection from hunting has allowed some populations to recover, although sea otters still face threats from disease, food shortages, pollution and shark bites.