At the Caldwell Zoo in Tyler, Texas we visit the Northern River Otters, who are always up for some fun. Otters have long, slim, torpedo-like bodies, and short limbs with webbed paws. They have a very soft underfur which is protected by their outer layer of long guard hair. This traps a layer of air, and keeps them dry and warm under water. Otters feed on fish and other water inhabitants, and some are experts at openinig shellfish. Otters are very playful and social animals. The Northern River Otters live predominantly in North America in freshwater rivers, lakes and streams, and in estuaries and both salt and freshwater marshes.