By Andria Harrold
Geographic Range
Baikal seals are endemic to Lake Baikal in Siberia and are found only this lake and connecting rivers. (Nowak, 1991)
Biogeographic Regions:
palearctic 
(native ).
Habitat
Pusa sibirica is the only seal that lives primarily in freshwater. It is endemic to Lake Baikal, and occasionally is found in rivers connecting to the lake. Ice conditions in the lake determine the seasonal movements and activities of these seals. In winter the lake is covered by ice that is 80 to 90 cm thick.
These animals are found in the following types of habitat:
temperate ; freshwater .
Aquatic Biomes:
lakes and ponds.
Physical Description
(110 to 286 lbs)
(4.26 ft)
Baikal seals are one of the smallest seals. Adults grow to a length of about 1.3 m. The adult coat is dark, with a silvery gray back and lighter yellowish gray front. Some individuals also have a spotted coat, but these are rare. Their fur is dense. Males are slightly larger than females. Baikal seals have stronger and larger forelimbs than many other species of seals. The head is rounded and the body spindle-shaped. The dental formula is 2/3 1/1 5/5 = 34.
Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .
Reproduction
Baikal seals breed at most once per year.
Breeding occurs in the spring, after pups are weaned. Usually mid-April to early June.
Baikal seals have a polygynous mating system.
Mating systems:
polygynous .
Mating takes place in the water at around the time the last pup is weaned, usually in May. Females experience a short period of delayed implantation. Gestation lasts for about nine months and the pups are born on lake ice from mid-February to March. Usually only one pup is born, but twins are not uncommon. If there are twins, both of them usually survive to weaning and then stay together for some time. At birth, pups weigh around 3 to 4 kg and measure from 65 to 70 cm in length. They are covered with a long, white, woolly coat that lasts for the first 6 weeks and then is shed and replaced by an adult coat.
Females tend to reach sexual maturity at 3 to 6 years of age and males at 4 to 7 years of age. Females can breed until they are about 30 years of age. About 88% of sexually mature females have pups each year.
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; delayed implantation .
Mothers nurse their pups for 2 to 2.5 months, except in the southern part of the lake where the ice breaks up earlier. Pups in the south are weaned prematurely and, as a result, are smaller.
Parental investment:
precocial ; pre-fertilization (provisioning, protecting: female); pre-hatching/birth (provisioning: female); pre-weaning/fledging (provisioning: female).
Behavior
During the winter, these seals are solitary. They usually molt on ice in late spring, but if the ice has already melted they finish their molt on shore. In 1990 and 1991, a number of juvenile seals were radio tagged. This tagging revealed that the seals traveled between 400 and 1600 km around the lake from September to May.
During the winter months, when the lake is primarily covered with ice, Baikal seals stay near breathing holes they have made. They keep these holes open by scraping them with their strong claws. Some seals may also use their head, teeth, and rear flippers. Adult seals have one breathing hole, but this hole has many auxiliary openings. Immature seals only use one breathing hole.
Baikal seals are most widely dispersed during the winter months. Mature males scatter throughout the lake. Mature females are usually found on the east shore. Male and female seals that have not yet reached sexual maturity are found on the west shore. Pregnant females remain on the ice for most of the winter.
At around the first of April, Baikal seals begin to come together to feed along new openings where the ice has melted. In May they move to the north end of the lake and stay there until they molt, which usually occurs in late May and early June. During the summer months, Baikal seals move to the southeast corner of the lake to use the rocks and shore for hauling out. When fall returns, they again begin to move to the areas where ice is forming.
Baikal seals are solitary animals, but several seals may congregate and share access holes. They will also gather at places where the habitat is most favorable. In spring, when they feed the most, 200 to 500 animals will gather in one area. The first to come are juveniles, then adult males, and, finally, new pups and their mothers. Large groups also form on the shores in the summer.
Key behaviors:
natatorial ; motile ; migratory ; solitary .
Food Habits
Baikal seals eat mainly fish in the pelagic genera Comephorus and Cottocomephorus. They also eat non-commercially valuable fish, such as golomyanka. These fish move to depths of 20 to 180 meters at night. Baikal seals will also eat invertebrates found in the lake. Most foraging for food occurs at twilight and night. Young seals have been observed feeding up to 100 m in depth. They have also been observed doing some short duration dives, most of which last under 10 minutes. Maximum diving time is estimated to be around 20 to 25 minutes, although some seals that are frightened can stay under 2 to 3 times longer.
Economic Importance for Humans: Negative
Baikal seals eat fish that are important to fishermen in Lake Baikal. Fish of the genus Comephorus make up a large part of their diet. These fish are commercially important and, as a result, these seals do some harm to the fishing industry.
Economic Importance for Humans: Positive
Baikal seals are often taken by hunters. About 2,000 to 3,000 pups are killed each year for their skins. Adult seals are also killed for their meat, pelt, and oil.
Ways that people benefit from these animals:
food ; body parts are source of valuable material.
Conservation Status
IUCN Red List: [link]:
Lower Risk - Near Threatened.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
Hunters can legally take Baikal seals. However, populations of these seals are still on the decline. Human disturbance and destruction of habitat are some major causes of this decline. Pollution from the paper industry is another cause. In 1987-1988 about 5,000 Baikal seals died from an infection caused by a form of Canine Distemper Virus. It is thought this virus was transmitted from dogs or other land mammals.
For More Information
Find Pusa sibirica information at
Contributors
Andria Harrold (author), Bethel College.
Andria Harrold (editor), Bethel College.
