Which lake is home to the world’s only exclusively freshwater seal species?

Lake Baikal is home to the world’s only exclusively freshwater seal species, the Baikal seal.

The Baikal seal, also called nerpa, is found naturally only in Lake Baikal in Siberia. Scientists think its ancestors reached the lake through ancient river systems, although the exact route remains debated. The species has adapted to Baikal’s cold, deep freshwater environment and spends much of its life beneath the ice or in the lake.

Baikal is also exceptional for its age, depth and biodiversity. It is the world’s deepest lake, reaching 1,642 metres, and is estimated to be about 25 million years old. Its isolation has allowed many species to evolve nowhere else.

The Baikal seal is sometimes confused with seals living in brackish or marine waters, but it is the only seal species whose natural range is entirely freshwater. Its population faces pressure from pollution, disease and changing ice conditions.