Although considerable variation exists among individuals, their fur is usually reddish to chocolate brown and marked with creamy or white blotches over the chest and throat. The head is broad with a short muzzle, small rounded ears, and a hairless nose pad. The teeth are adapted for consuming fish, with large sharp upper canine teeth, curved lower canines, and sharp carnassial teeth. The jaws are similarly adapted, with the mandibular fossa fitting so snugly into the condyle on the lower jaw that the latter cannot move sideways, making it easier to capture and hold fish.