The Baikal Seal (Pusa sibirica) is a unique pinniped species in that they live entirely in freshwater as opposed to at-sea. They are native to Lake Baikal in southern Russia and are solely found here.Despite this relatively small distribution, the population at the lake is deemed to be equal to the potential carrying capacity of the area, suggesting they are doing fairly well, and therefore justifying a classification as Least Concern at the current time. Estimated population size = 108,200.
P. sibirica are true or earless seals, and the smallest seal species in the world (males ♂ up to 1.4 m long/ 130 kg, females ♀ up to 1.2 m/ 90 kg). They have round bodies, short hind flippers, and short, but broad, fore flippers with well-defined digits and thick claws. Their necks are relatively long and their heads small, with a blunt-tipped muzzle and a steep forehead. Facial features include large, forward-set eyes, and long, pale whiskers. Most Baikal Seals are greyish or pale brown in colour, with a coat that darkens in water. Infrequently they display faint marbling.
The primary diet of P. sibirica are lake fish, namely the two species of Comephorus. During summer, another 15 or so species may feature, whereas in winter, this generally falls to only around 4 different species. In winter, longer foraging dives may be necessary during periods of heavy ice cover. There is evidence to suggest that diurnally, seals concentrate on catching pelagic fish, whereas nocturnally they use tactile cues to hunt swarming crustaceans nearer the surface.
Sexual maturity – males ♂ ~7 years old/ females ♀ 3-6 years old.
A polygamous structure is thought to exist for P. sibirica, withmatingtaking place in the water, leading to delayed implantation of a couple of months and a 9 month gestation period. P. sibirica are a solitary seal and the female alone hauls out on the ice in the winter to birth, with white-coated pups born from February to April. Females build their own independent lairs on the ice to shelter their pups, as well as entry and breathing holes for use, which form their home range. These do not overlap with those of others. The pups themselves then expand the dens by digging further tunnels at a very young age. During the first few weeks they do not enter the water, and it takes until 6-8 weeks until they lose their white fluffy coat and gain a silvery grey one. Nursing continues for a relatively long period of around 10-12 weeks, after which time the female introduces the pup to solid foods in the den. Moulting takes place around this time, and soon after the ice starts to melt, the dens collapse, and the young are left to fend for themselves. P. sibirica holds the record for the longest-living species known, with individuals reaching nearly 60 years old. Not only this but they have been seen still reproducing successfully up to their mid-forties.