Lake Baikal (which is the largest, oldest and deepest freshwater lake in the world) in Russia is the only freshwater body in this world where seals live. The zoological name of these seals is 'Pusa Sabricia'. They are commonly known as Nerpa.

The origin of the species is still uncertain, although the most accepted theory suggests descent from the ringed seal 'Phoca hispida' and that the species may have been isolated geographically for about 500,000 years.

They are famous for swimming upstream rivers. They are also known for travelling and changing from one river to another. They can hold their breath for about 70 minutes! It is because of two reasons. The first reason being the extra blood present in their body and the second being the extraordinary capacity of their blood to hold oxygen for longer time.

They are the world’s smallest 'pinnipeds' (a carnivorous aquatic animal of the order Pinnipedia). at 1.1–1.4 metres (3.6–4.6 feet) long and 50–130 kg (110–290 pounds), but some female fur seals weigh less. Females reach sexual maturity at 3-6 years of age, males at 4-7 years. Baikal seals have been known to dive for as long as 43 minutes. It has been estimated that adult males can live up to 52 years of age, females to 56 years.

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