The Nerpa or Baikal Seal (Pusa sibirica) is a species of earless seal endemic to Lake Baikal, the world's largest fresh water lake by volume, located in Siberia near its border with Mongolia. Nerpa are unique among seals in several ways: They and two subspecies of the Ringed Seal are the only seals to spend their whole lives in fresh water. They are the longest-lived of seals (up to 56 years in females). They feed their young on milk twice as long as other seals. It remains a scientific mys… (More on Nerpa)