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Otters are any of thirteen aquatic or amphibious mammal species in the subfamily lutrinae. They are carnivorous mammals related to weasels, and subsist on diets of fish, shellfish and small mammals. Otters live in rivers and oceans throughout the world, and are beloved for their charming appearance and abilities.
Probably the most recognizable member of the family is the Eastern and Northern Pacific sea otter. These ocean-going creatures lives in coastal regions along the western borders of North America and parts of Russia, and is notable for its eating habits. Sea otters often use rocks to pound open the shells of clams or crustaceans. Their habits are quite easily observed, as sea otters float on their backs at the surface, trying to smack their meals open. Much of the affection for sea otters is attributed to their care for pups, which they hug tightly to their chests as they swim.
Sea otters are considered to be a keystone species, vital to maintaining the ecological balance of coastal environments. Bottom dwelling sea-urchins make up a large proportion of sea otters’ diet. Urchins, when unharvested, multiply in huge numbers and can destroy fragile ecological systems such as kelp forests. The introduction of otters into urchin infested areas has been shown to restore the balance of the environment and promote species diversity.
The remaining twelve species of otter are usually classified together as river otters. All twelve feature long, powerful tails, which the marine species lacks. All species of otter have high metabolic rates, meaning they must constantly consume food in order to maintain body temperature and function in the water. Most species consume between 15% and 25% of their body weight each day. Unlike sea otters, which remain in the ocean almost constantly, river otters tend to stay close to land.
Otters are believed by some experts to have consistently playful personalities. Observations of the animals have shown that otters will slide repeatedly down snow-covered slopes, for no apparent reason other than enjoyment. Captive otters play with a variety of toys such as balls and frisbees. Some otters have even been known to have favorite toys in particular that they guard as possessions.
Some species of river otter appear to be monogamous, at least in captive environments. The Asian small-clawed species shares pup-raising duties between parents and older siblings. Pairs of this species will stay together through many breeding cycles, and may even form lifelong pair-bonds.
A rarely seen species is the giant otter of South America. These animals grow to be over 6 ft (2 m) long, and live in family groups of up to ten otters. They are quite noisy and are often referred to as river dogs for their persistent, carrying barks. Listed as endangered by the International Union for the Conservation of Nature (IUCN,) giant otters are threatened by habitat depletion, fur poaching and competition from fishermen for prey. Estimates suggest that giant otters have lost over 80% of their natural habitats, but recent efforts have been made by South American governments to federally protect some of their remaining home ranges.
Otters are beautiful and charming creatures, and their presence in the wild is often of vital importance to their natural environment. While some species maintain healthy populations, others, such as the giant otter and hairy-nosed otter of south Asia, are in danger of extinction. Conservation organizations to help otters are widespread, and always in search of donations and volunteers to aid their efforts.