Taxonomy LutrinaeĬladogram showing relationships between sea otters and other otters The full genome of the northern sea otter ( Enhydra lutris kenyoni) was sequenced in 2017 and may allow for examination of the sea otter's evolutionary divergence from terrestrial mustelids. In some respects, though, the sea otter is more fully adapted to water than pinnipeds, which must haul out on land or ice to give birth. In comparison to cetaceans, sirenians, and pinnipeds, which entered the water approximately 50, 40, and 20 million years ago, respectively, the sea otter is a relative newcomer to a marine existence. The modern sea otter evolved initially in northern Hokkaidō and Russia, and then spread east to the Aleutian Islands, mainland Alaska, and down the North American coast. One related species has been described, Enhydra reevei, from the Pleistocene of East Anglia. įossil evidence indicates the Enhydra lineage became isolated in the North Pacific approximately 2 million years ago, giving rise to the now-extinct Enhydra macrodonta and the modern sea otter, Enhydra lutris. Genetic analysis indicates the sea otter and its closest extant relatives, which include the African speckle-throated otter, Eurasian otter, African clawless otter and Asian small-clawed otter, shared an ancestor approximately 5 million years ago. The only living member of the genus Enhydra, the sea otter is so different from other mustelid species that, as recently as 1982, some scientists believed it was more closely related to the earless seals. It is unique among the mustelids in not making dens or burrows, in having no functional anal scent glands, and in being able to live its entire life without leaving the water. The sea otter is the heaviest (the giant otter is longer, but significantly slimmer) member of the family Mustelidae, a diverse group that includes the 13 otter species and terrestrial animals such as weasels, badgers, and minks. For these reasons, the sea otter remains classified as an endangered species. The recovery of the sea otter is considered an important success in marine conservation, although populations in the Aleutian Islands and California have recently declined or have plateaued at depressed levels. A subsequent international ban on hunting, sea otter conservation efforts, and reintroduction programs into previously populated areas have contributed to numbers rebounding, and the species occupies about two-thirds of its former range. Sea otters, whose numbers were once estimated at 150,000–300,000, were hunted extensively for their fur between 17, and the world population fell to 1,000–2,000 individuals living in a fraction of their historic range. Its diet includes prey species that are also valued by humans as food, leading to conflicts between sea otters and fisheries. In most of its range, it is a keystone species, controlling sea urchin populations which would otherwise inflict extensive damage to kelp forest ecosystems. Its use of rocks to dislodge prey and to open shells makes it one of the few mammal species to use tools. Its foraging and eating habits are noteworthy in several respects. It preys mostly on marine invertebrates such as sea urchins, various mollusks and crustaceans, and some species of fish. The sea otter inhabits nearshore environments, where it dives to the sea floor to forage. Although it can walk on land, the sea otter is capable of living exclusively in the ocean. Unlike most marine mammals, the sea otter's primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. Adult sea otters typically weigh between 14 and 45 kg (30 and 100 lb), making them the heaviest members of the weasel family, but among the smallest marine mammals. This beautifully illustrated slipcase is a great addition to any child's story collection.The sea otter ( Enhydra lutris) is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Nature Stories Slipcase Young children can discover the wonderful rainforest and woodland animals and habitats in this original fiction box set. From tales of tigers and gorillas to butterflies and deer, there are many charming characters to meet, all with their own special stories and messages to share. These are a collection of great quality products, grouped together to give you amazing value. Get more for less with The Work’s expertly hand-picked Book Bundles. Once Upon A Time: The First Books We Remember Reading.3 for £5 Mix & Match Kids Picture Books.
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