J. David Solf
Alaska Department of Fish and Game
Wildlife Notebook Series, 1972
"How retired the otter manages to live here!
He grows to be four feet long, as big as a
small boy, perhaps without any human being
getting a glimpse of him."
H. D. Thoreau, Walden
A SINGLE SPECIES OF land otter (Lutra canadensis) ranges over most of North America north of Mexico. It is found throughout Alaska with the exception of the Aleutian Islands, the off-shore islands of the Bering Sea and the area adjacent to the Arctic coast east of Point Lay.
Land otters of other species inhabit most of the rest of the world. All are amphibious members of the family Mustelidae along with mink and sea otter. Animals in this family produce a more or less disagreeable scent that is discharged from a pair of anal glands.
General Description: The North American land otter is a thick-set mammal with short legs, a neck no smaller than its head, inconspicuous ears and a muscular body that is broadest at the hips. Its tail is powerful and a little more than a third as long as its head and body. Only the hind feet are webbed. Adults weigh 15 to 35 pounds and are 40 to 60 inches in length. On the average, females are about 25 per cent smaller than males.
When prime, their fur appears black-brown, with the belly slightly lighter in color than the back. The chin and throat are greyish. This fur consists of a very dense undercoat overlaid with longer guard hairs which are usually removed by furriers.
Land otters appear to have a well-developed sense of smell and very acute hearing. Their vision is not good and may be better underwater than above. Several sets of strong whiskers on their faces are used by the animal in hunting and avoiding obstructions.
These animals are graceful swimmers and propel themselves in the water primarily by flexing their body from the head to the tip of the tail. They can swim at about 6 miles per hour and can go faster for short distances bv "porpoising" along the surface. Land otters dive to depths of at least 60 feet and can stay submerged for more than four minutes. They can run as fast as a man and on hard snow or ice reach speeds of more than 15 miles per hour by alternately running and sliding.
About half of a land otter's time is spent sleeping. Both young and adults are fond of play. They manipulate rocks or sticks, play tag and hide-and-seek, duck each other, wrestle and slide on mud or snow.
Signs of land otter activity are seen more often than the animals themselves. They travel several miles overland between bodies of water and develop well-defined trails that are used year after year, and they may flatten and dig up the vegetation or snow over an area of several square yards. There are usually scats, twisted tufts of grass and small piles of dirt and vegetation here. Urine and scent deposited on these piles serve as identification. During the winter, they dig elaborate tunnels and feeding dens within the snow over a frozen lake or bay where fluctuations in water level leave cracks for them to come and go.
Life History: Land otters in Alaska breed in spring, usually in May. Mating can take place in or out of the water. One to six pups (usually 2-3) are born the following year between late January and June after a gestation period of nine to 13 months. Delayed implantation (a period of arrested embryonic growth) accounts for this variation in the length of gestation.
The pups are born toothless and blind in a den that is usually a subterranean burrow. Their eyes open seven weeks later. When about two months old, they begin to leave the den and shortly thereafter start to swim and eat solid food. They are taught to swim by the female who must coax or drag them into the water. Pups are weaned when about five months old but stay with their mother until shortly before her next litter is born.
Land otters are sexually mature when two years old. A female will then mate with the male of her choice and will produce one litter each year. They can live and breed for more than 20 years.
Food Habits: Land otters in Alaska hunt on land and in fresh and salt water. They eat snails, mussels, clams, sea urchins, insects, crabs, shrimp, octopi, frogs, a variety of fish and occasionally birds, mammals and vegetable matter. Aquatic organisms no bigger than a man's finger are usually eaten at the surface of the water; larger food is taken ashore.
If a fish or other animal is too big to be eaten at one meal, the remains are abandoned and become available to other flesh-eating mammals and birds. Scraps left out of the water may be a significant part of the food available to some scavengers when snow and ice are present.
Social Habits: Land otters are often found in groups. A family unit is made up of a female and her pups, with or without an aduIt male. They usually travel over an area of only a few square miles. The female appears to dominate the rest and may drive other animals away from a small area around the den where her pups are living.
Other groups may consist of an adult male and female, a litter of pups that remain together after the family separates, or a group of bachelor males. Male groups usually consist of fewer than 10 individuals. Larger numbers that are occasionally seen together may represent a temporary association of neighboring groups. The groups have no apparent leader. They travel together and operate as a social unit but do not cooperate in hunting or share what is caught. Travel is over a wide area and apparently there are no exclusive territories. Fighting among them is extremely rare although they are wary of strange individuals.
Vocalizations: Land otters produce a variety of noises. They growl, caterwaul and whine. When alarmed, individuals emit an explosive "hah!". When two or more are together they often produce a mumbling noise that seems to be a form of conversation. A good imitation of this is made by closing the lips and rapidly uttering "hm" several times in a deep voice. A bird-like chirp apparently expresses anxiety. It is most often heard when members of a group become separated.
Human Utilization: Land otters have no significant enemies except man. They are occasionally killed unintentionally when they become entangled in fish nets or trapped in crab pots. In each of the past 20 years, between one and four thousand were harvested in Alaska for their pelts. They are usually taken in steel traps but natives in Prince William Sound hunted them with the aid of dogs of a nondescript type that were small enough to enter an otter den. The dogs could usually drive out the otter without a fight.
J. D. Solf
[Map of the range of the land otter in Alaska]