Sea otter  (Enhydra lutris)

The sea otter, the smallest marine mammal in the world, is well adapted for its predominately aquatic lifestyle, possessing a strong, rudder-like tail and large hind-feet that act as flippers (2). Unlike other marine mammals, sea otters do not have blubber and instead rely on their fur to keep warm in the water (4); their reddish-brown coat is the densest of any mammal, consisting of around 100,000 hairs per cm² (2). The natural oils produced by the fur provide a waterproof quality (5).