The Ladoga ringed seal, is a freshwater subspecies of the ringed seal which are found entirely in Lake Ladoga in northwestern Russia. The subspecies evolved during the last ice age, about 11,000 years ago. As the glaciers retreated and water levels changed, the Baltic ringed seal was trapped in freshwater lakes and separated from the Arctic ringed seal.
It is related to the even smaller population of Saimaa ringed seals in Lake Saimaa, a lake ...
that flows into Ladoga through the Vuoksi River.
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