THE NAME. The Baikal seal, or nerpa, Phoca sibirica Gmelin, 1798.
THE GENEALOGY. The animal Kingdom: Animalia, Zoobiota = Animals; the Type is Chordata = the Chordates.
The Class is Mammalia Linnaeus, 1758 = Mammals.
The Order is Pinnipedia Illiger, 1811 = the Pinnipedia; the Family is Phocidae Brooker, 1828 = the Seals, real [earless] seals; the Genus is Phoca Linnaeus, 1758 = Common [real] seals.
THE NEAREST RELATIVES and the origin
The seal – Phoca hispida Schreber, 1775, the Caspian seal – Phoca caspica Gmelin, 1788.
The origin is from the ancestor common with the north seal.
CHARACTERISTIC FEATURES (distinctive marks)
One-colour, without spots. The back is usually one-colour, olive-grey or brownish-silver-grey, the sides and stomach are lighter and more yellow. The young ones are silver-grey, the newborns are yellowish-white. The claws on the fore flippers are almost as wide as the spans between them. The claws are with a central rib. The fore edge of the nose bones is without projection in the middle. The second tip of the low molars is just a bit bigger than the neighbouring tips.
Nektobyont, spends bigger part of its life in water.
Pagophyl, its life cycle is closely connected with ice in the periods of complete ice cover and ice decay. They spend whole winter in water using holes made in thin ice, for breathing. During ice decay they migrate to the northern part of the lake. In summer they spread all over the lake, part of the animals make up coastal rookeries. In autumn while the water is growing cool and ice is being formed, the animals first migrate to shallow, early freezing parts of the lake (the eastern coast), by December the seals start spreading all over the lake.
Old animals have clearly seen features of sexual dimorphism. It is a pagophyl, for mating and child-bearing are on ice. The mating period is the end of February until the beginning of May. The pregnancy is 11 months long, the first 3-3.5 of them is the latent period, i.e. the impregnated ovule doesn’t develop. Pregnant females come to the ice and make nests under the snow, where they give birth to their babies.
Child-bearing is from late February to late March. They feed their babies on milk for 1.5-3 months.
THE ADDRESS (habitat). The whole Lake Baikal water area.
In summer they live everywhere both in the open Baikal and in the coastal zone. The minor part of the population make summer coastal rookeries (the main ones are in the Ushkanyi Islands, the bay of Ayaya, the cape of Pongonye, a part of the shore near the Ledyanaya river – the capes of Sev Kedrovogo, Khoboi). In winter they live under ice, mostly in the open (deep water) parts of the lake (adult animals), immature ones live in shallow water parts (the Selenga shallow water etc.).
THE PROFESSION. Ichthyophag.
The favourite food is the small and big golomyankas, the bull-heads.
THE LIFE PERIODS (postnatal ontogenesis)
Belyek (white one) until the age of one month.
Kumutkan (khubun, khubunok) (the Buryat word khubun means a wild animal’s cub) is the animal which has once shed its hair (from 1 month to 1 year of age).
Argal is a mature male.
Pubescence is at the age of 4-6 with females, 1-2 years later with males. The average weight is 50 kg.
The maximum weight of males is 130-150 kg, of females – 110 kg. The males’ maximum length is up to 1.5-1.6 m, females are up to 1.5 m long. Their linear growth stops by the age of 17-19, but their weight grows some years more and is possible until the end of their lives. Their maximum lifespan is 56 years.
Closely set teeth with bigger number of additional tips – for eating very small fish. Bigger eyeballs – for eating in dim light and in twilight.
More powerful claws of the fore flippers – for making and keeping holes in the ice about one metre thick, for breathing through them. Higher hemoglobin concentrations in the blood – for deep water diving in search of food for long time with switched-off breath. The daily ration is 3-5 kg of fish. Food digestion in the stomach – 2-3 hours. Maximum diving depth is 300 m. Maximum swimming speed is 20-25 km/h. Maximum underwater stay is more than 1 hour.
POPULATION STRUCTURE AND QUANTITY
Sex structure: females – 58 per cent, males – 42 per cent. Age structure – 1-9 years old – 78.7 per cent, 10-19 years old – 17.0 per cent, 20-29 years old – 3.0 per cent, 30-39 years old – 0.9 per cent, 40-49 years old – 0.3 per cent, 50 years old and older – 0.1 per cent. The quantity is 80-100 thousand head.
The passport is compiled by I.A. Kutyrev, N.M. Pronin.