An otter is a carnivorous mammal that lives in water. They are found in many parts of the world, including North America, Europe, Asia, and Africa. Otters have a long, slender body with a thick, bushy tail. Their fur is waterproof and keeps them warm in the water. Otters have sharp teeth and claws that they use to catch and eat fish, amphibians, and other small animals. The claw of an otter is called a spur.