North American River Otter

NORTH AMERICAN RIVER OTTER
Lontra canadensis
(Schreber, 1776)

lon-tra can-e-den-sis

Description:
The North American River Otter is a stocky mammal with a long, fusiform body, short legs, muscular neck no smaller than the head, and a long tail that is thick at the base and tapers to a tip. The pelage is short and very dense, ranging from pale brown to black. The toes are webbed. The dental formula is incisors 3/3, canines 1/1, premolars 4/3, molars 1/2.

Adults may attain the following dimensions: total length 900-1346 mm; length of tail 350-507 mm;; length of hind foot 112-140 mm; length of ear 22-25 mm; weight 5-14 kg. Males are larger than females.

This species can be distinguished from all other carnivores in Kansas by its aquatic adaptations, including the muscular tail, webbed toes, and dense pelage.

Distribution:
The North American River Otter once occurred in streams, lakes, reservoirs, wetlands, and along coastlines from Alaska through Canada into all but the most arid areas of the United States. In Kansas, the species occurred along all the major rivers and many permanent streams. Over-trapping and the changes in streams brought about by agricultural development led to the disappearance of the river otter in much of the Great Plains and surrounding areas and in the Midwest. The species evidently was extirpated in Kansas by soon after the beginning of the Twentieth Century. However, in 1983 and 1984, 19 river otters from Idaho and Minnesota were reintroduced on the South Fork Cottonwood River in Chase County. That reintroduction was at least partially successful, but even more successful was the immigration of river otters from Missouri, where multiple reintroductions established a population of 11,000 otters by the year 2000. North American River Otters also may be colonizing eastern and central Kansas from Oklahoma and Nebraska. Today, river otters can be found along portions of at least the Cottonwood, Neosho, Spring, Marmaton, Marais de Cynes, Deleware, Kansas, and Missouri rivers in eastern Kansas and in the unreclaimed surface mining areas in southeastern Kansas. Although river otters normally remain near water, they occasionally disperse overland between watersheds.

Close relatives of the North American River Otter evolved in Eurasia in the Pliocene. Lontra dispersal into North America occurred during the Kansan glaciation of the Pleistocene and has been found in numerous Pleistocene deposits. Specimens recovered from one late Pleistocene deposit in South America suggest that this species once occurred there as well as in North America.

(, Museum Voucher) (, Observation) (, Literature Record)
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Occurrence Summary:
55 Total Records
51 Museum Vouchers
4 Other Observations

Some county occurrences indicated below may be too imprecise to map above.
County Breakdown: County Name (# occurrences):
Allen (1); Bourbon (2); Chase (2); Cherokee (8); Coffey (4); Crawford (3); Doniphan (2); Douglas (4); Jefferson (2); Johnson (1); Labette (1); Leavenworth (1); Linn (10); Lyon (4); Marshall (1); Morris (1); Neosho (2); Not given (1); Riley (1); Saline (1); Wabaunsee (1); Washington (1); Wyandotte (1);

Natural History:
The primary habitat requirement for river otters is permanent water with abundant fish or crustacean prey and relatively high water quality. Otters are highly mobile and often move in response to shifting availability of food. Otters are more social than most other mustelids, and they forage both in groups and singly. Groups may consist of a female and her recent young, a group of males, or several mothers and their juveniles. River Otters are active year-round, but they are most active at night and during crepuscular hours. Dens may be under tree roots, in hollow logs or trees, in muskrat lodges or beaver dams, or in abandoned burrows. Otters are known for their playful activity. Often an otter will repeatedly slide down a muddy bank into the water much like a child at a water park.

The diet of North American River Otters reflects their aquatic habits. The largest component of the diet is fish, which are taken in proportion to their availability. Secondary components include crayfish and frogs. Others foods consumed opportunistically include large insects, reptiles, birds, fruits, muskrats, young beaver, and mollusks.

In Kansas, river otters have few natural enemies. Farther south they may be eaten by alligators, and in marine habitats, they fall prey to killer whales. When on land in Kansas, river otters may be preyed upon by Bobcats, Coyotes, Cougars, and dogs. More important, however, is mortality caused by humans: trapping, shooting, roadkills, and inadvertent captures in nets and on set lines. Accidents and diseases also cause deaths.

In Kansas, most mating of river otters takes place in March and April. Females are in heat for 42 to 46 days during which time the males follow scent trails of the females. Copulation may occur in water or on land. True gestation lasts from 61 to 63 days but, because the fertilized egg does not implant in the uterus for 8 months or more, the time between copulation and parturition may reach 10 to 12 months. Litter size usually ranges from 1 to 3. The fully furred but blind and toothless young are cared for by the female (males provide no paternal care). Kits take their first solid food at 9 to 10 weeks and are fully weaned by 12 weeks. Juveniles remain with their mothers for 37 to 38 weeks.

Occurrence Activity:

Remarks:
Lontra canadensis lataxina is believed to have been the original subspecies of North American River Otter in Kansas. Reintroductions presumably included animals representing the subspecies Lontra canadensis canadensis, Lontra canadensis lataxina, and Lontra canadensis pacifica.

Since 2011, North American River Otters are considered harvestable furbearers in Kansas and can be trapped with the proper licenses or a nuisance wildlife control permit.

Bibliography:

1952	Cockrum, E. L. Mammals of Kansas. Univ. Kansas Publ. Mus. Nat. Hist. 7:1-303. ():
1987	Choate, J. R. Post-settlement history of mammals in western Kansas Southwestern Naturalist 32(2):157-168
1998	Lariviere, S, and L. R. Walton Lontra canadensis Mammalian Species 587():1-8 plus erratum
2006	Boyle, S. USDA Forest Service, Rocky Mountain Region, http://www.fs.fed.us/r2/projects/scp/assessments/northamericanriverotter.pdf [24 November 2008]1-56. pp.
2008	Timm, R. M., G. R. Pisani, J. R. Choate, N. A. Slade, G. A. Kaufman, and D. W. Kaufman http://www.ku.edu/~mammals, . pp.
2009	Shardlow, Mackenzie R. Factors affecting the detectability and distribution of the North American River Otter. Thesis. Kansas State University, Manhattan, Kansas. 82pp.

Account Last Updated:
11/19/2019 2:37:48 PM

Kansas Mammal Atlas