Otters are members of the weasel family. There are 13 species throughout the world including the northern river otter, sea otter, Eurasian otter and the giant otter. Otters are semi-aquatic mammals. They have short legs, long bodies and webbed feet. With the exception of the sea otter, all have long muscular tails. Otters live near bodies of water. They sleep by floating on the surface of the water and they hunt down below the surface. Otters are playful animals and appear to engage in various behaviors for enjoyment.
Otters mainly eat fishes and other aquatic invertebrates.River otters' diets consist largely of crayfishes, crabs, and other aquatic invertebrates; fishes; and frogs. Giant otters eat mainly fishes and crabs. Cape clawless and Asian small-clawed otters feed mainly on crabs and other crustaceans, molluscs, and frogs.A sea otter's diet consists mainly of slow-moving fishes and marine invertebrates including crabs, sea urchins, abalones, clams, mussels, and snails.An otter's high metabolic rate is important for generating body heat and requires a substantial amount food. River otters eat 15% to 20% of their total body weight each day.