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Lontra canadensis

(North American Otter)

Overview

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Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in Dutch:

Rivierotter

Common Names in English:

North American Otter, Canadian otter, North American River Otter, northern river otter, Otter, river otter

Common Names in French:

Loutre Du Canada, Loutre De Rivi, loutre de rivière, loutre de rivière

Common Names in Spanish:

Nutria De Canad?, Nutria Norteamericana, Nutria-De R, Nutria-de río norteamericana, Nutria-de río norteamericana

Description

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Physical Description

Species Lontra canadensis

The River Otter is long and cylindrical in body shape . It has short legs and a short, thick neck. The snout is short and broad. The ears are small, and the tail is long and thick at the base . The feet are webbed .

The otter's dense, water-repellent fur is critical to its survival in chilly waters. Grooming the fur provides the otter with maximum levels of insulation.

Many land animals do not see well while under water, as the water distorts their vision. Otters compensate for this distortion by having strong eye muscles that change the shape of their lenses, correcting their vision while under water.

Color:

The short, dense fur is dark brown, with the face , chin, and throat having a grayish sheen.

Size/Age/Growth

Adults are 0.9 - 1.2 m (3 - 4 ft ) in total length and weigh 5 - 10.4 kg (11 - 23 lbs ).

Habitat

The River Otter ranges widely along rivers, streams , swamps , and marshes. An individual otter may move from 77.2 - 96.6 km (48 - 60 mi ) along a waterway in a season , but the average is from 4.8 - 16.1 km (3 - 10 mi). Throughout its home range , a River Otter has "pulling out spots" where it makes "scent posts" by gathering and piling up water-logged leaves, sticks , or aquatic plants , and marking them with feces and urine. A scent post informs other otters of the River Otter's presence, but otters do not defend territories against one another.

Typically found at an altitude of 0 to 498 meters (0 to 1,634 feet).[2]

Ecology: Historical records indicate that river otters were well established throughout most major drainages in the continental United States and Canada prior to European settlement (Hall 1981). The continent’s largest otter populations occurred in areas with an abundance and diversity of aquatic habitats such as coastal marshes, the Great Lakes region, and glaciated areas of New England (Nilsson 1980; Toweill and Tabor 1982; Melquist and Dronkert 1987). In addition, riverine habitats in interior regions supported smaller, but viable, otter populations (Nilsson 1980).
North American river otters prefer bog lakes with banked shores containing semi-aquatic mammal burrows and lakes with beaver (Castor canadensis) lodges , and they avoid water bodies with gradually sloping shorelines of sand or gravel (Reid et al. 1994b). In Maine, use of watersheds by river otters is negatively associated with the proportion of mixed hardwood-softwood stands in forested areas adjacent to waterways and positively associated with the number of beaver flowages, watershed length, and average shoreline diversity (Dubuc et al. 1990). In Idaho, river otters prefer valley over mountain habitats, and they select valley streams over valley lakes, reservoirs , and ponds (Melquist and Hornocker 1983). Logjams are used intensively where present (Melquist and Hornocker 1983). In Florida, abundance of North American river otters is lowest in freshwater marshes, intermediate in salt marshes, and highest in swamp forest . During the dry season , L. canadensis will retreat from marshland and move to permanent ponds where water is available and food is more concentrated (Humphrey and Zinn 1982). In Idaho and Massachusetts, habitat features preferred for latrine sites include large conifers, points of land , beaver bank dens and lodges, isthmuses, mouths of permanent streams, or any object that protrudes from the water (Melquist and Hornocker 1983; Newman and Griffin 1994).The diet of the North American river otter is comprised mostly of fish that are abundant, midsized, and close to shore (Larsen 1984; Stenson et al. 1984), as well as amphibians (mostly frogs ) and crustaceans (mainly crayfish) (Knudsen and Hale 1968; Reid et al. 1994a; Sheldon and Toll 1964). Small mammals, mollusks, reptiles , birds, and fruits are consumed opportunistically (Gilbert and Nancekivell 1982; Greer 1955; Hamilton 1961; Morejohn 1969; Verbeek and Morgan 1978; Wilson 1954). North American river otters have few natural predators in the water: alligators (Alligator mississippiensis), American crocodiles (Crocodylus acutus), and killer whales (Orcinus orca). They are considerably more vulnerable on land or ice where bobcats (Lynx rufus), cougars (Felis concolor ), coyotes (Canis latrans), dogs (Canis familiaris) and wolves (Canis lupus) can kill adults (Melquist and Dronkert 1987; Melquist and Hornocker 1983; Route and Peterson 1991; Toweill and Tabor 1982). Most mortality , however, is human-related and includes trapping , illegal shooting, road kills, and accidental captures in fish nets or set lines (Jackson 1961; Melquist and Hornocker 1983).North American river otters can reach 13 years of age in the wild and up to 25 years of age in captivity (Melquist and Dronkert 1987; Stephenson 1977). Females usually do not reproduce until 2 years of age, although yearlings occasionally produce young (Docktor et al. 1987; Hamilton and Eadie 1964). Males are sexually mature at 2 years of age (Hamilton and Eadie 1964). North American river otters usually breed from December to April (Hamilton and Eadie 1964; Liers 1951), gestation lasts 61-63 days, and young are born between February and April (Hamilton and Eadie 1964; Melquist and Hornocker 1983). Litter size may reach five (Park 1971) but usually ranges from one to three (Docktor et al. 1987; Hamilton and Eadie 1964; Tabor and Wight 1977).[3].


List of Habitats:

[more info]

Biology

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Diet

Forages for foods such as rough fish , crayfish, mollusks, crabs, amphibians , rodents, birds, eggs , and small reptiles . Contrary to popular opinion , the River Otter does not affect the quality or quantity of sport fish populations. If anything, it contributes to a healthy fish population by culling out the weak and sick individuals.

The otter preys on the fish that are the most available and the slowest. The slower fish include carp , suckers and catfish. Fish that are abundant and are found in large schools, like sunfishes and perches , are also important. The faster fishes , trout and pike , are taken less frequently by otters. Otters also eat frogs , insects, birds and small mammals.[1]

Reproduction

River Otters mate in late winter and early spring . After mating, a delay of 290 - 380 days occurs before the actual development of embryos begins. Gestation takes 60 - 63 days once implantation of the embryos in the uterus occurs. In March or April, from 1 - 6 young are born in a leaf- and grass-lined den constructed in an old muskrat lodge , abandoned burrow, or hollow tree close to a water source. The young, called kits, are developed enough to leave the den with the female at 10 - 12 weeks of age. The female River Otter teaches the young to swim and hunt for food. The male may assist the female in caring for the young once they leave the den. Young remain with the female until the breeding season after their birth. A River Otter is capable of breeding once it reaches two years of age.

Behavior

The River Otter is an extremely intelligent animal and exhibits a high level of curiosity. When encountered along a waterway , it will stop and crane its neck to look at a human, if the person is moving slowly and is not acting in a threatening manner. Otters have a playful nature and will play both by themselves and with other otters. They will make slides on mud banks into the water and use them over time to the point where they become deep troughs .

Unlike the infamous, bad-tempered wolverine and badger, the otter loves a game. Games are most fun in a group, and here a family of otters excels. Tag , hide-and-seek, keep-away and wrestling may start the day. A muddy riverbank becomes a free-for-all slide that improves with use. Zoom, kerplunk! Then up to the top of the slope for another turn . After a day of sliding, tail chasing, stick juggling, and a few rolls in the grass or snow, it's into a den for a huddled snooze. Play behavior indicates intelligence, and the otter doesn't come up short.[1]

The River Otter is most active from dawn to midmorning and again in the evening.

The River Otter has few natural predators , but there are reports of it being preyed upon by American Alligators, Bobcats, and Coyotes. River Otters have lived for 20 years in captivity, but 5 - 7 years is the average in the wild.

Taxonomy

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Notes

Name Status: Accepted Name .

Last scrutiny: 15-Aug-2007

River otters from North and South America were recognized as distinct from their European river otters by van Zyll de Jong (1987). However, the genus name Lontra is rarely used in the present literature, and numerous authors still use Lutra (Kellnhauser 1983). Herein, Lontra is used in concordance with van Zyll de Jong (1972, 1987) and Wozencraft (2005).[3].

Similar Species

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No other large aquatic mammal in North America looks like a River Otter. Both the Beaver and the Muskrat are stocky and squat in build, whereas the River Otter is long and slender.

Members of the genus Lontra

ZipcodeZoo has pages for 8 species and subspecies in this genus:

L. canadensis (North American Otter) · L. canadensis canadensis (North American River Otter) · L. canadensis kodiacensis (Kodiak River Otter) · L. canadensis mira (Northern River Otter) · L. canadensis sonora (Southwestern Otter) · L. felina (Marine Otter) · L. longicaudis (South American River Otter) · L. provocax (Southern River Otter)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 29, 2008:

Identifiers

Footnotes

  1. New Mexico Wildlife. New Mexico Department of Game and Fish Version of April 24, 2009. [back]
  2. Mean = 74.720 meters (245.144 feet), Standard Deviation = 84.250 based on 85 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
  3. Sefass, T. & Polechla, P. 2008. Lontra canadensis. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 01 February 2012. ... [back]
Last Revised: 2012-07-14