caspianseal

It is so-far unclear as to how these seals became isolated in the landlocked Caspian Sea, and hypotheses have been put forth to explain this enigmatic situation. One of the most widely known hypotheses argues that the seals reached the Caspian during the Quaternary period from the north when continental ice sheets and proglacial lakes were growing. It may also be the case that the seals invaded this region during the late Pliocene cooling around 2 million years ago. It is generally thought that the Caspian seals, along with the Baikal seals (another isolated species of seals in a Eurasian basin), descended from the Ringed seal.