The
Ladoga ringed seal (;
Pusa hispida ladogensis), is a
freshwater subspecies of the
ringed seal (
Pusa hispida) 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 (including Ladoga seals) was trapped in freshwater lakes and separated from the
Arctic ringed seal.