Lontra canadensis (Schreber, 1777)
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publication ID |
https://doi.org/ 10.5281/zenodo.5714044 |
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DOI |
https://doi.org/10.5281/zenodo.5714105 |
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persistent identifier |
https://treatment.plazi.org/id/038F87D4-CA46-FFA8-CFE1-3F3EFAECF921 |
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treatment provided by |
Conny |
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scientific name |
Lontra canadensis |
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North American River Otter
French: Loutre du Canada / German: Nordamerikanischer Fischotter / Spanish: Nutria neértica
Other common names: River Otter
Taxonomy. Lutra canadensis Schreber, 1776 View in CoL ,
Eastern Canada.
Seven subspecies are recognized.
Subspecies and Distribution.
L. c. canadensis Schreber, 1776 — E Canada (Maritime Provinces, Ontario & Quebec), NE USA (Maine through New York) and Great Lakes of USA (Michigan and Wisconsin).
L. c. kodiacensis Goldman, 1935 — Alaska (Kodiak and Shuyak Is).
L. c. lataxina Cuvier, 1823 — E & SE USA.
L. c. mira Goldman, 1935 — S Alaska (Prince of Wales I), SW Canada (Vancouver I).
L. c. pacifica Rhoads, 1898 — W USA and W Canada.
L. c. periclyzomae Elliot, 1905 — W Canada (Queen Charlotte Is).
L. c. sonora Rhoads, 1898 — SW USA (Arizona, California, Colorado, Nevada, New Mexico & Utah). View Figure
Descriptive notes. Head-body 70-73 cm (males), 58: 3-71.3 cm (females), tail 42-47 cm (males), 31.7-40 cm (females); weight 7.7-9.4 kg (males), 7.3-8.4 kg (females), adult males are approximately 5% larger than females. The North American River Otter has an elongated body, short limbs, and a tail that is flattened dorso-ventrally. The pelage is short and very dense, varying in color from brown to black, with a grayish upper chest, throat, and chin. The rhinarium is bare and there are long vibrissae on each side of the face. All four feet are fully webbed and equipped with small claws. The skull is flat, with a broad rostrum and large braincase. Dental formula: I 3/3, C 1/1, P4/3.M 1/2 =36.
Habitat. North American River Otters are found along streams, rivers, ponds, lakes, reservoirs, and in saltwater marshes. Generally, they prefer waterways with well-vegetated shorelines, and avoid areas with no shoreline vegetation. They inhabit the murky waters of southern alluvial valleys as well as the crystal-clear waters of rocky mountain streams. In many areas, they occur in close association with American Beavers; Beaver ponds provide prey and dens/rest sites.
Food and Feeding. The diet is mainly fish, but also includes amphibians, crustaceans (especially crayfish), rodents, molluscs, reptiles, birds, and fruits. In many areas, the abundance and availability offish is the primary determinant of North American River Otter abundance. Typically, fish are consumed in inverse proportion to their swimming abilities: slow-moving species are captured and eaten more often. In coastal areas, the fish eaten are those that are abundant, intermediate in size, and found close to shore. North American River Otters hunt by sight and by touch. They inspect logjams, pools of deeper water in shallow streams, areas below waterfalls, natural eddies, or any other areas likely to hold fish and other prey. Upon detection, prey are pursued until captured. In shallow or murky water, North American River Otters hunt and detect prey with their vibrissae or by feeling with their forefeet. They can remain underwater for up to four minutes, and can swim at speeds of 11 km /h. They may hunt in small family groups, herding fish to shore or to each other to facilitate capture.
Activity patterns. Mainly nocturnal, with some crepuscular activity; diurnal activity increases during colder months. Active year round, even when water freezes in winter. Rest sites are in dry bank dens, Beaver lodges, or other natural cavities accessible from underwater.
Movements, Home range and Social organization. North American River Otters are highly mobile, aquatic animals and can travel more than 40 km in a single day. Daily movements average 4-5 km for males and 2-3 km for females. They typically travel in water and are able to swim long distances under ice during the winter. North American River Otters may travel long distances over land from one watershed to another. When traveling on land, they often slide instead of bounding, especially if snow is present or when going downhill on slippery ground. When sliding, they push forward with their back legs, while the front feet are tucked under the belly. They will also play on steep banks next to water, repeatedly climbing up the bank and sliding back down into the water. North American River Otters have a complex social system, which varies across their range. They often occur in groups of up to 15 individuals; the largest groups are found along coastal shorelines. These groups mainly consist of a female with young. In coastal areas, groups consist either of adult females with young, or male groups. The cohesiveness of male groups disappears during breeding, when each male attempts to find and mate with numerous females. Home ranges may reach 275 km ” for males and 135 km? for females. In south-eastern Minnesota, annual home ranges of males were 3-2 times greater than those of females, and annual core areas of males were 2-9 times greater than those of females; 69% of the individuals exhibited core-area overlap. In general, conspecifics were not excluded from home ranges or core areas and signs of cooperation were evident, suggesting that they were social rather than territorial. Population densities range from one per 4 km of water in Idaho to one per 1-25 km of coastal water in Alaska.
Breeding. North American River Otters are polygynous. Mating occurs from December in the south to April in the north. Implantation of the fertilized eggs into the uterus is delayed for eight months; embryonic development lasts 61-63 days. Births occur from February to April, usually in a bank den or an abandoned Beaver lodge. In south-eastern Minnesota, two females used man-made brush piles as maternal dens, four used small limestone caves, one used a cavity in the roots of a big-toothed aspen (Populus grandidentata) and one used a American Beaver bank den. Dens were located a mean of 316 m from the nearest body of water. Seven of eight females placed dens outside of their normal activity areas, and all females appeared to select den sites that were protected from flood events. Litter size is one to five. The young are born furred, blind, and toothless. The eyes open after 30-38 days, and weaning occurs after twelve weeks. Sexual maturity is reached after two years. Males do not provide parental care.
Status and Conservation. CITES Appendix II. Classified as Least Concern in The [UCN Red List. North American River Otters are considered to be fairly common throughout their range. However, one subspecies, L. ¢. sonora, may be of concern in Mexico. One threat is water pollution, which not only reduces the availability of prey, but also affects reproduction due to bioaccumulation of toxic pollutants. In coastal areas, oil spills are the most severe threats. Throughout their range, they are harvested for their fur, but this controlled harvest does not constitute a major threat when habitat conditions are suitable. Reintroductions have been successful in areas where North American River Otters were once common.
Bibliography. Gorman, Erb, McMillan & Martin (2006), Gorman, Erb, McMillan, Martin & Homyack (2006), Green (1932), Hall (1981), Lariviere & Walton (1998), LeBlanc et al. (2007), Melquist & Hornocker (1983), Reid et al. (1994), Serfass (1995), Serfass & Rymon (1985), Shannon (1989), Van Zyll de Jong (1972), Wozencraft (2005).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
