Lee Richardson Zoo
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North American River Otter

River otterOrder: Carnivora - Canines, felines, bears

Family: Mustelidae - weasels, skunks, badgers, ferrets

Scientific Name: Lontra canadensis

 

Description Head and body length is 18-32 inches, tail length is 12-22 inches.  Weight may be up to 33 pounds, with males generally larger than females.  The head is rounded and flattened.  The ears are small.  The neck is short and thick.  Fur on the upper parts is varying shades of brown, with light brown or gray on the belly.  The throat may have a silver or white patch.  The fur has a heavy, soft, oily underfur overlain by glossy, smooth guard hairs.  The feet are webbed and the tail is slightly flattened, muscular at the base, and tapers to a point.  Like all mustelids, they have a long body with relatively short legs.

RangeHome Range:  All of North America except extreme NE Canada, the SW States of the US and Mexico.  Formerly found in Kansas, extirpated in 1904, reintroduced in 1983, and now established again across the eastern half of Kansas.

 

Habitat Type:  Found in many aquatic environments from saltwater estuaries to inland streams, marshes and rivers.  Seem to prefer areas with diverse vegetation and aquatic life.

 

Reproduction:  The female does not excavate her own den; instead, she uses that of another animal or a natural shelter.  Several males may compete for the right to breed with a female.  Utilize delayed implantation to time birth with weather.  Mating occurs in winter or spring, with offspring born from January through May.  Gestation is 288-380 days, but actual embryonic development time is only 60-63 days.  Litter size varies from 1-6, usually 3-4 kits.  Young are born with dark brown or black fur, and eyes and ears closed, but with well developed claws.  Eyes open at one month, and kits begin to follow their mother at 2 months to learn to swim and fish.  They are weaned at 5-6 months.  The young generally stay with their mother until just before the next litter is born.  Males do not help raise the young.  Maturity for both sexes is reached at 2, but males do not breed until 5 years.

 

Diet in the Wild:  Mainly fish with crustaceans, amphibians, reptiles and occasionally mammals and birds.

 

Diet in the Zoo:  Triple A brand feline meat.  Minnows, crayfish, and bits of lobster occasionally given as treats.  

 

General Information:  Otters are somewhat territorial, and both sexes will avoid other river otters; however, territorial defense has not been documented, and several territories may overlap.  River otters mark territories with scratches and latrines or “scent posts.”  These posts are piles of debris that the otter scrapes together and urinates or defecates on.  When threatened, they have anal musk glands that can emit a foul odor.  These animals are primarily nocturnal or crepuscular, but have been known to be active during the day.  Otters may use several temporary shelters, but usually have one permanent shelter.  Frequently, the entrance to the shelter is underwater on the side of a riverbank.  The burrow then slopes upward so that the den is well above water level.  They also utilize beaver dens, even when beaver are present.  When underwater, their nostrils and ears are closed.   Otters are very playful animals, and several signposts mark an area where an otter is active:  frequently, there are “slides” of mud or snow where otters slide into the water.  There may also be “rolling areas” used to roll and groom the fur, as well as “runways” that connect different water sources. 


The guard hairs of their fur trap air in the pelt. The air can be seen escaping as bubbles when the otter first enters the water.  Though trapping for their luxurious pelt has caused populations to decline over most of North America, river otters have also been adversely affected by pesticide pollution and habitat destruction.  They have been reintroduced in several midwestern states including Kansas, Missouri, Oklahoma, and Nebraska.  KDWP released 17 otters in Eastern Kansas in 1983-1984.  Missouri released over 800 otters from 1982-1992.  Kansas releases and immigration from surrounding states have reestablished otters in Kansas.  They are now known to range over the eastern ½ of Kansas, with greater concentrations at Perry Lake, Glen Elder Reservoir, Flint Hills National Wildlife Refuge, and Marais des Cygnes Wildlife Refuge.

 

Predators:   Few natural enemies, but sometimes attacked by bobcats, coyotes or other mammalian predators, and by some birds of prey or alligators.

 

Bibliography

Animal. (Smithsonian Institute).  David Burnie and Don E. Wilson.  2001.  DK Publishing, New York.  pg. 201.

 

Distribution and Mesohabitat Characteristics of River Otters in Eastern Kansas.Master Thesis by Andrea OstroffDec. 2001.  Emporia State University.

Mammals in Kansas. James W. Bee et al.  1981. University of Kansas Press. Lawrence, Kansas.  pg. 209-211.

 

The Natural History of Living Mammals.  William Voelker.  1986.  Plexus Publishing, Medford, New Jersey.  pg. 210-214.

 

Personal communication.  Furbearer Biologist KDWP.  8/20/2004.  Peek, Matt. 

 

"Send in the Clowns." Kansas Wildlife.  May/June. 1986: pg. 27-32.  Fox, Lloyd.

 

Reintroduction of the River Otter Lutra canadensis in Kansas.  Master Thesis by Donald Eccles.  May 1984.  Emporia State University.

 

Smithsonian Book of North American Mammals.  Don Wilson and Sue Ruff.  1999.  Smithsonian Institution Press, Washington and London.  pg. 179-180.

 

Walkers Mammals of the World Sixth Edition Volume I. Ronald M. Nowak. 1999. Johns Hopkins University Press. Baltimore, Maryland.  pg. 738, 740-741.