The belly has a silvery sheen. There are 4 mammae. Otter tails are fur covered, wide at the base but tapering down to a tip. Otter's feet are webbed but with 5 distinct toes and a footpad on each foot. Otters possess 36 teeth with which they dine on fish, frogs, crayfish and other aquatic invertabrates.
Entrances are underwater.
Otters usually confine themselves within a homerange of 15 miles. Otters are playful animals that are fond of transforming muddy or icy banks into slides. Otters in cold areas often travel across ice by taking a few running steps and then sliding on their bellies. They can go up to 15 miles an hour this way. River Otters by Laima Dingwall is the best book on river otters that I have found for adults or children.