[2] The most recent population estimates are 80,000 to 100,000 animals, roughly equaling the expected carrying capacity of the lake.

In addition, the morphological structures in both species suggest they are descended from Arctic ringed seals.

[7] They may have swum up rivers and streams or possibly Lake Baikal was linked to the ocean at some point through a large body of water, such as the Paratethys Sea, West Siberian Glacial Lake or West Siberian Plain, formed in a previous ice age.

[8] The areas of the lake in which the Baikal seals reside change depending on the season, as well as other environmental factors.

[5] However, in recent years, migrations to the southern half of the lake have occurred, possibly to evade hunters.

[1] In addition, new techniques, such as netting breathing holes and seal dens to catch pups, have been introduced.

[6] In 2004–2006, about 2,000 seals were killed per year according to official Russian statistics, but in the same period another 1,500–4,000 are thought to have died annually due to drowning in fishing gear, poaching, and the like.

Pesticides such as DDT and hexachlorocyclohexane, as well as industrial waste, mainly from the Baikalisk pulp and paper plant, are thought to have exacerbated several disease epidemics among Baikal seal populations.

The chemicals are speculated to concentrate up the food chain and weaken the Baikal seal's immune system, making them susceptible to diseases such as canine distemper and the plague, which was the cause of a serious Baikal seal epidemic that resulted in the deaths of 5,000–6,500 animals in 1987–1988.

[3] Canine distemper is still present in the Baikal seal population, but has not caused mass deaths since the earlier outbreaks.

[1] The most serious future threat to the survival of the seal may be global warming, which has the potential to seriously affect a closed cold-water ecosystem such as that of Lake Baikal.

[1] The only known natural predator of adult Baikal seals is the brown bear, but this is not believed to occur frequently.

[1] The seal pups are typically hidden in a den, but can fall prey to smaller land predators such as the red fox, the sable and the white-tailed eagle.

With a combination of delayed implantation and a nine-month gestation period, the Baikal seals' overall pregnancy is around 11 months.

The females, after giving birth to their pups on the ice in late winter, become immediately impregnated again, and often are lactating while pregnant.

Since the pup avoids breaking the surface with these tunnels, this activity is thought to be mainly for exercise, to keep warm until they have built up an insulating layer of blubber.

While moulting, they refrain from eating and enter a lethargic state, during which time they can die of overheating, males especially, from lying on the ice too long in the sun.

[5] During the spring and summer, groups as large as 500 can form on the ice floes and shores of Lake Baikal.

[1] They feed mainly during twilight and at night, when golomyankas occur in depths as shallow as 10–25 m (33–82 ft).

In early autumn, before the entire lake freezes over, they migrate to bays and coves and hunt Kessler's sculpin, a fish that lives in silty areas and, as a result, usually contains grit and silt in its digestive system.