Sea Otter
Enhydra lutris – Excessive hunting lead to the extermination of the sea otter from most of its range along north Pacific coasts. It recovered to about half its previous population levels through international protection, but is declining again. The sea otter is one of the few mammals that uses tools: It employs a stone to smash open crabs, sea urchins, and mollusks caught on its shallow dives to the seabed. Intelligent animals, sea otters have learned to rip open sunken, discarded drink cans in which a small octopus may hide. Sea otters are important ecologically since they control the numbers of sea urchins, which eat a lot of growing kelp. Exposed coasts are protected against heavy wave action by the kelp beds.
Where sea otter numbers have declined, urchins have increased and prevented proper growth of the floating kelp beds. Sea otters are generally solitary animals, although they sometimes gather in groups. They are exclusively marine and usually fairly sedentary, but some occasionally go on long tourneys, of about 100 miles (160 km) along the coast. The sea otter lives in the cold waters of the north Pacific and spends a lot of time floating at the surface, grooming, or sleeping among the kelp beds. It is one of the smallest sea mammals and needs very effective insulation to reduce loss of body heat. Its fur is the densest known, with more than 600,000 hairs per square inch (93,000 per sq. cm)-twice the density of a fur seal’s coat.
For centuries the thick pelt was highly valued, and the sea otter was ruthlessly hunted off the coasts of Kamchatka in Russia and in the eastern Pacific. Explorations by 18th century navigators expanded the trade in skins, and colonization of Alaska by the Russians intensified the pressures on the species across the north Pacific. The skins became the world’s most valuable fur, each pelt worth the equivalent of a seaman’s wages for an entire year. Records show that over 750,000 sea otters were killed between 1750 and 1850, and that a single shipment of 17,000 skins was made in 1803. Sea otters were easily hunted from kayaks; hunters chased the animals until they were too breathless to dive, then speared them. Each body would be skinned in the kayak and the next otter sought out. Living along the coast, and with no safety at sea, the otters could be hunted until every last one had been caught.
Success Story
Sea otters do not breed rapidly, so they became extinct over wide areas. In 1911 the Russians, Americans, and British (on behalf of Canada) agreed on total protection for the sea otter throughout the north Pacific. Gradually numbers have increased, and they are appering again in many of their former habitats. It was thought that sea otters were extinct on the California coast, but in 1938 a few were found. Numbers have grown to more than 2,000. In fact, fishermen now complain that there are too many. Animals have been transported to Washington state, Oregon, and Alaska, successfully repopulating those coasts; reintroductions to the Pribilof Islands off Alaska appear to have been less successful. The sea otter, having been reduced to fewer than 1,000 animals in the whole North Pacific, seems to have made a comeback. However, the otters still face a variety of threats-some of them natural, such as the risk of predation by killer whales. Others are man made and include oil spills and other pollution.
Enhydra lutris- Sea otter
- Family: Mustelidae
- World population: About 15,000 (1999)
- Distribution: Coasts of California, eastern Russia (Kamchatka and Commander Islands). Successfully reintroduced to coasts of Alaska, Oregon, and Washington
- Size: Length head/body: 30-36 in (75-90 cm); tail: 11-13 in (28-32 cm); height at shoulder: 8-10 in (20-25 cm). Weight: 30-85 lb (14-40 kg)
- Form: Dark-brown coat with a cream, blunt looking head. The feet are completely webbed, the hind ones forming flippers
- Diet: Crabs, shellfish, sea-urchins, fish, and other marine animals; about 13 lb (6 kg) daily
- Breeding: Breeds all year round, but most births occur in early summer. Only 1 pup is born each year. Life span can exceed 20 years
- Related endangered species: Giant otter (Pteronura brasiliensis),European mink (Mustela lutreola)
