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Northern River Otter (Lontra canadensis) - Wiki
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Northern River Otter
From Wikipedia, the free encyclopedia
[Photo] North American River Otters, Lontra canadensis (per Schreber, 1777. More commonly used, but allegedly incorrect latin name: Lutra canadensis). Taken at San Francisco Zoo on 08/29/2005 by Dmitry Azovtsev - http://fotki.azovtsev.com/
The Northern River Otter, Lontra canadensis, is a North American member of the Mustelidae or weasel family. It is also known as the North American River Otter. This species can be found all across North America, inhabiting inland waterways and coastal areas in Canada, Alaska, the Pacific Northwest, the Atlantic states, and the Gulf of Mexico. However, their numbers have significantly dropped since Europeans came to the Americas. (Linzey, 2002)
Description
L. canadensis have streamlined, muscular bodies with short legs, webbed toes and a long muscular tail. The North American river otter’s body measure is somewhere between 25.98" to 42.13", and their tail measure is between 12.40" to 18.11" (a river otter’s tail makes up 30 to 40% of the total length of its body). It can weigh between 6 and 31 pounds. River otters have a round and small head and eyes, short yet powerful legs, and have large whiskers. Otters have sexual dimorphism, as the male is larger than the female. They have glossy dark brown fur and their throat is often silver grey. Otters are powerful swimmers, but can also travel quickly on land and often propel themselves into a rapid slide on their bellies on snow or ice; they also like to slide down river banks into the water. North American river otters have nostrils that close underwater and their fur is soft and dense; both of these adaptations help them to live underwater. On land, the river otters can run up to 18 miles per hour. Their current life span is 10-15 years in the wild, but they can live up to 25 years in captivity. (Fact Sheet: North American River Otter)
Habitat
Northern river otters have their dens on land, and they hunt in a wide variety of aquatic habitats, including lakes, rivers, inland wetlands and swamps, coastal marshes and even the open ocean. In many areas of the United States and Canada, the damming activities of the beaver creates ideal habitat for otters.
Diet and natural history
Otters mainly eat fish but also eat insects, frogs, crustaceans and sometimes small mammals. On occasion some larger river otters will attack and kill water birds such as ducks, geese, and even herons. They are capable of swimming in circles, which creates a whirlpool-like motion that brings fish from the bottom of the water up to the top. They are generally more active at night, dusk and dawn, but are active during the day where undisturbed by human activity. They use musk and urine to mark the land bordering their territories. They often use dens built by other animals, sometimes killing beavers or muskrats to take over their lodges. Females evict males while babies are still young, the male will return later however to help care for them when half-grown. (Dewey, 2004) North American river otters usually mate once a year in late winter or usually early spring. Males often mate with several females during the breeding season. They have a gestation period of 2 months, and the pups are weaned for 3 months. The size of the litter can range from 1-6 pups, but usually there are only 2-3. (Dewey, 2004) There is a delay in the implantation of the fertilized egg, so that the young are born in late winter or early spring. Mating occurs in water.
Personality
Like their relatives, the weasels, river otters are highly active predators. If an otter is not sleeping, it's moving. They are very playful, chasing, sliding, swimming, jumping, wrestling. This makes them popular for exhibits. However, they are not friendly towards humans if raised in captivity. Usually a captive raised river otter becomes very aggressive towards humans when it reaches sexual maturity, and thus they do not make good pets. There are times when otters have remained tame through their adult life, or have been taken from the wild as adults. However, "tame" is a relative term, even the most human-friendly otter will still bite and scratch, sometimes quite badly. They can be highly curious animals and have been known to follow trout fisherman along the opposite bank.
Conservation status
Otters are trapped for their highly-prized fur. Over harvest in the 1800s has led to their disappearance from many parts of their historical range. Trapping is still permitted in some areas where otters remain abundant. In other areas, the otter is being restored to places where it may have long since been extirpated, such as the Hudson River. The North American river otter is not a nationally endangered species, but it is endangered in many states and it is threatened in others. Over-hunting, habitat destruction, and inadequate laws protecting the North American river otter are major factors where otters remain threatened. Ever since the discovery of the americas, hunters have captured and killed the otters for their pelts. Hunting still continues today, their pelts being worth over $100 (USD) each. Over 30,000 otter pelts are sold each year in the United States and Canada.
Otters eat many game fish in the habitats that they live in. These game fish are better fish that people fish for food. Efforts have been made to bring the otter back from endangerment. Since 1986, the National Park Service has reintroduced over 100 North American river otters back into the wild. (Linzey, 2002)
Care In Captivity
Otters are only suited for professional exhibits or care. Their diet is flexible. Some groups feed their otters a variety of fresh water creatures in addition to live fish, while others live on a diet of pre-killed rodents. They need access to fresh water deep enough to swim and play in, and this water will need to be changed regularly or filtered. Some groups add chlorine to the water to reduce bacteria and algae growth, but this may result in skin problems for the otter. As they are very active, they are easy to train for medical exams, demonstrations, and behavioral enrichment. Common enrichment objects include ice with food frozen in it, floating balls, and segments of wide pipe.
http://en.wikipedia.org/wiki/Northern_River_Otter
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North American River Otter
ORDER: Carnivora
FAMILY: Mustelidae
GENUS: Lontra
SPECIES: canadensis
I. DESCRIPTION:
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.
III. DIET:
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).. |
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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. |
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North American River Otter
(Lontra canadensis)
Members of the weasel family, playful river otters enjoy sliding down muddy and snowy hills, bouncing objects on their paws, playing tag, and wrestling.
Description
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.
Range
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.
Habitat
River otters can make themselves at home in nearly any inland waterway, as well as estuaries and marine coves.
Diet
These otters eat fish, frogs, crayfish, mollusks, other invertebrates, and small mammals.
Behavior
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.
Fun Facts
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. |
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Scientific Name: Lontra canadensis (Schreber, 1777)
Synonyms: Lutra canadensis Schreber, 1777
Common Names:
English – North American River Otter, Northern River Otter, North American Otter, Common Otter
French – Loutre de rivière, Loutre du Canada
Spanish – Nutria de Canadá, Nutria Norteamericana, Nutria-de río norteamericana |
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