|North American River Otter
Long, slender, sleek body, weighing approximately 20 pounds (9 kg) and about two and a half feet (76 cm) long. Head is small and round, with small eyes and ears; prominent whiskers. Legs short, but powerful; all four feet webbed. Tail long and slightly tapered toward the tip with musk-producing glands underneath. The short dense fur is dark brown. Chin and stomach are reddish yellow, tinged with gray. Females are a third smaller than males.
II. GEOGRAPHICAL RANGE AND HABITAT:
All of the United States and Canada except the tundra and parts of the arid southwestern United States. Allied species occur in Mexico, Central and South America, as well as Eurasia. Found in streams, rivers, lakes, estuaries, and salt- and freshwater marshes.
Fish, crayfish, frogs, turtles, and aquatic invertebrates, plus an occasional bird, rodent or rabbit. Because otters prey most easily on fish that are slow and lethargic, much of the diet consists of "rough" fish like carp, suckers, catfish, and sculpins. Zoo diet: fish or horsemeat with vegetables. Feline diet with fish three times a week and vitamin E twice a week.
IV. LIFE CYCLE/SOCIAL STRUCTURE:
Spends two-thirds of the time on land. (Leopold says they live primarily in water.) The female mates in the spring shortly after giving birth to two to four young (or she might skip a year). The new litter of youngsters will not begin to develop until late in the fall. This process, known as delayed implantation, enables the fertilized eggs to mark time within her, receiving only sparse ration to stay alive for several months. Then within her body an obscure signal awakens the tiny embryos which resume their growth.
The otter kits start their life in a burrow in a river bank, usually an abandoned muskrat den. Born blind and helpless, they are nursed by the female for a month. Venturing out of the den, they rough-house and play in the shallow water, where their mother teaches them to swim and hunt.
V. SPECIAL ADAPTATIONS:
Almost impervious to cold because of an outer coat of coarse guard hairs, plus a dense, thick undercoat that helps to "water-proof" the animal. They have no blubber; it's the fur that keeps them warm. They seem to enjoy frolicking in ice and snow. Perianal scent glands are used for identification, defense, marking territory, and trail marking. Small ears and nostrils can be tightly closed when in water; they are excellent swimmers and divers. During a dive, pulse slows to a tenth of the normal rate of 170 beats a minute, thereby conserving oxygen. Both diurnal and nocturnal.
VI. INTERPRETIVE INFORMATION:
Otter droppings are called spraints. King James I of England kept a pack of tame otters to catch fish for his table, even appointing a "Keeper of the King's Otters" to tend them.
VII. STATUS IN WILD:
The river otter is native to northern and central California, being found in the delta region of the Sacramento and San Joaquin Rivers, where it sometimes dens in thick tules. In California the river otter is fully protected under law and may not be taken at any time. Population densities are low, even in the best habitat. Over 30,000 pelts are sold annually in the United States and Canada. On Appendix II of CITES (threatened)..
|North American river otter
Scientific name: Lontra canadensis
Country: USA, Canada
Continent: Central & North America
Diet: Fish - piscivore, crustaceans - crustacivore, frogs - ranivore, also rodents and worms.
Food & feeding: Carnivore
Habitats: Fresh water, coast
Conservation status: Not Threatened
Relatives: Sea Otter, Skunk, Weasel
Description: This species of otter is one of the largest, growing up to 1.5 m long (including the tail) and weighing up to 11 kg. The male (dog) otter is larger than the female (bitch). The otter's body is streamlined and the feet are webbed so they are well adapted for swimming. When they go underwater their nostrils and ears close. Their stiff whiskers are used to feel around as they search for food. When swimming on the surface, legs are used to perform a doggy-paddle, but when hunting underwater, the legs are folded close against the body and forward motion is powered instead by undulating the body and tail, just like a seal.
Lifestyle: In the wild they spend a lot of time foraging for food, so in the Zoo food is often hidden in different parts of the enclosure so they have to search for it as they would in the wild. They are mostly active early in the morning or late afternoon. They dive in pursuit of fish, dragging bigger ones to the bank to eat. They can remain beneath the water for upwards of a minute.
Family & friends: Female otters rear their young without help from the male (dog) otter. Otters are territorial, each defending a section of prime river bank or coast.
Keeping in touch: Otters use anal glands to mark their territory so that other otters know who they are. They deposit special piles of excrement scented with anal gland smells, usually on top of a prominent rock or log, along the river bank or shoreline.
Growing up: Otters usually give birth about two months after mating, but the female otter can delay the time when the fertilised egg begins to develop into a baby by up to nine months (this is called delayed implantation). The young are usually born in an abandoned musk rat burrow. Usually two or three young are born in early April, but litters range from one to five and are sometimes born as early in the year as January. The babies weigh about 100-200 g at birth, are weaned at 3-4 months and become sexually mature in their second or third year. In captivity, they may live up to 22 years of age.
|North American River Otter
Members of the weasel family, playful river otters enjoy sliding down muddy and snowy hills, bouncing objects on their paws, playing tag, and wrestling.
Built for swimming, river otters have a streamlined body, short legs with webbed feet, dense fur that keeps otters warm, a tapered tail, small ears, and nostrils that can close underwater. They can grow to be more than a meter long, from head to tail, and weight up to 14 kg.
Once abundant in U.S. and Canadian rivers, lakes, and coastal areas, river otters have suffered from fur trapping, water pollution, habitat destruction, pesticides, and other threats. Today, they can be found in parts of Canada, the Northwest, upper Great Lakes area, New England, and Atlantic and Gulf Coast states.
River otters can make themselves at home in nearly any inland waterway, as well as estuaries and marine coves.
These otters eat fish, frogs, crayfish, mollusks, other invertebrates, and small mammals.
Male and female otters are generally solitary, except when adult females care for their juvenile offspring, who disperse by the time the otters give birth again.
At the Zoo
North American river otters can be seen in the Zoo's Beaver Valley. Their cousins, Asian small-clawed otters, can be seen at the Small Mammal House.
The largest of the 13 species of otter is the giant otter, reaching a length of up to 1.8 m and known as the river wolf in Peru. The smallest is the Asian small-clawed otter, less than a meter long.
North American river otters can dive to a depth of 60 feet.