![]() Its whiskers ( vibrissae) are long and thick, enhancing their senses. It differs from the European otter by its longer neck, narrower visage, the smaller space between the ears and its shorter tail. Large male North American river otters can exceed a weight of 15 kilograms (33 lb). Tail lengths range from 30 to 50 centimetres (12 to 20 in). About one-third of the animal's total length consists of a long, tapered tail. Its body length ranges from 66 to 107 centimetres (26 to 42 in). An average adult male weighs about 11.3 kilograms (25 lb) against the female's average of 8.3 kilograms (18 lb). The North American river otter has long whiskers that are used to detect prey in dark waters. ![]() The North American river otter's streamlined shape allows it to glide through the water. periclyzomae (Elliot, 1905) – ( Queen Charlotte Islands, British Columbia) Allen, 1898) – (Alaska, Canada, northern U.S., south to central California, northern Nevada, and northeastern Utah) mira (Goldman, 1935) – (Alaska, British Columbia) kodiacensis (Goldman, 1935) – ( Kodiak Island, Alaska) canadensis (Schreber, 1777) – (eastern Canada, U.S., Newfoundland) The otters migrated to North America and southwards again across the Panamanian Land Bridge, which formed 3 Mya. The New World river otters originated from the Old World river otters following a migration across the Bering Land Bridge, which existed off and on between 1.8 million and 10,000 years ago. Fossils of a giant river otter dating back 3.5 Mya (during the Pliocene) have been found in the US Midwest however, fossils of the modern river otter did not appear in North America until about 1.9 Mya. These analyses suggest they diverged in the Miocene epoch 23.03 to 5.33 million years ago (Mya), which is "much earlier" than indicated in the fossil record. Molecular biological techniques have been used to determine when the river otter and the giant otter ( Pteronura brasiliensis) of South America diverged. In a new classification, the species is called Lontra canadensis, where the genus Lontra includes all the New World river otters. Lutra was the early European name (from Latin), and the specific epithet canadensis means "of Canada". The North American river otter was first classified in the genus Lutra. Other documented common names are American otter, Canada otter, Canadian otter, fish otter, land otter, nearctic river otter, and Prince of Wales otter. The mammal was identified as a species of otter and has a variety of common names, including North American river otter, northern river otter, common otter and, simply, river otter. The North American river otter was first described by German naturalist Johann Christian Daniel von Schreber in 1777. A number of reintroduction projects have been initiated to help halt the reduction in the overall population. North American river otters are very susceptible to the effects of environmental pollution, which is a likely factor in the continued decline of their numbers. In some regions, though, their population is controlled to allow the trapping and harvesting of otters for their fur. The range of the North American river otter has been significantly reduced by habitat loss, beginning with the European colonization of the Americas. Occasional reports also show the river otter eating other small animals, such as mice, squirrels, birds, and even dogs that they've attacked and drowned. The most common fish consumed are perch, suckers, and catfish. Fish is a favored food among the otters, but they also consume various amphibians (such as salamanders and frogs ), freshwater clams, mussels, snails, small turtles and crayfish. North American river otters, like most predators, prey upon the most readily accessible species. Female North American river otters give birth in these burrows, producing litters of one to six young. The den typically has many tunnel openings, one of which generally allows the otter to enter and exit the body of water. It establishes a burrow close to the water's edge in river, lake, swamp, coastal shoreline, tidal flat, or estuary ecosystems. The North American river otter, a member of the subfamily Lutrinae in the weasel family (Mustelidae), is equally versatile in the water and on land. The river otter is protected and insulated by a thick, water-repellent coat of fur. An adult North American river otter can weigh between 5.0 and 14 kg (11.0 and 30.9 lb). The North American river otter ( Lontra canadensis), also known as the northern river otter and river otter, is a semiaquatic mammal that only lives on the North American continent, along its waterways and coasts.
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