North American river otters are semi-aquatic - which means that they spend their time living on land and in the water. They have webbed hands and feet, and a very strong tail for swimming. Sensitive whiskers help them hunt for their prey - like fish, frogs, and crustaceans, and they can hold their breath for up to eight minutes underwater! River otters live in lake, river, swamp, and estuary ecosystems across North America. They are sensitive to environmental pollution, and only thrive where the water is clean. A clean and healthy habitat means a clean and healthy otter! River otters live and play in Humboldt’s watersheds, and they depend on clean water and a healthy food web to support them! Dirty water contaminates the fur and feathers of wildlife, making them unable to stay dry or warm. River otters do not have a layer of blubber - or fat - like marine mammals do, so they need their fur to keep them warm in the cold water. River otter fur is very special. The longer, oily hairs on top help repel water, while the soft hairs underneath keep them warm. The special hairs even trap bubbles of air - which act as insulation! When the watersheds are clean, wild otters maintain healthy, waterproof fur by rolling in dirt, sand, and leaves just like the Zoo otters do!