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2010-01-28 digital edition

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2010-01-28 / Community News

River Otters

It appears that river otters may be increasing in number or at least expanding their range. Over the last couple of years otters have turned up in some unexpected places in the district. Otters are best known for their playful behavior. They have long, streamlined bodies, short legs, and a robust tapered tail, all of which are well adapted to their mostly aquatic habitat. They have prominent whiskers just behind and below the nose, thick muscular necks and shoulders, and feet that are webbed between the toes. Their short but thick, soft fur is brown to almost black except on the chin, throat, cheeks, chest, and occasionally the belly, where it is usually lighter, varying from brown to almost beige. Adult males usually attain lengths of nearly 48 inches and weights of about 25 pounds, but may reach 54 inches and 33 pounds. Females have 4 mammae on the upper chest and are slightly smaller than males.

River otters originally occurred in most of the United States that had adequate wetland habitat. Otters were extirpated from much of their historic range due in part to water pollution and pesticides bio-magnified in fish which makes up most of the otter’s diet. Shellfish, crayfish, amphibians, reptiles, and crabs in coastal marshes make up the balance of their diets. The loss of ponds and other wetland habitat that resulted from the extirpation of beaver in the late 1800s may have also adversely affected populations of river otters more than the pollutants. Recent increases in the range and numbers of river otters in response to the return of beaver has been dramatic, particularly in the southeastern United States. River otters are almost invariably associated with water (fresh, brackish, and salt water), although they may travel overland for considerable distances. They inhabit lakes, rivers, streams, bays, estuaries, and

associated riparian habitats. They occur at much higher densities in brackish marshes and inlets, and in other coastal habitats than farther inland. Vegetative cover and altitude do not appear to influence the river

otter’s distribution as

much as do good or adequate water quality, the availability of forage fish, and suitable denning sites.

The young, called kits, are born around January and February in the south with litter size ranging from 2 to 4. The kits remain with the mother throughout the fall and into the winter. River otters are mostly nocturnal, but they are frequently active during daylight hours in undisturbed areas. They are powerful swimmers and are continuously active, alert, and quick—characteristics that give them immense aesthetic and recreational value. Seasonally, they may travel distances of 50 to 60 miles along streams or lake shores, and their home ranges may be as large as 60 square miles. So if you see a short, long tailed black cat like animal that you do not recognize there is a good chance that you were fortunate enough to see a river otter.

If you would like to contact your local biologist, see our website at; wildlifebiologist.

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