The species is also known as the Baikal seal. Actually, this type of seals is the only true "freshwater" one. The two others types (Caspian and ringed seals) inhabit both seas and oceans.

The average length of the adult's body is about 5.4 ft .These seals usually stop elongating at the age of 17-19, while their weight continues to increase till the end of their life.

The life expectancy of the Baikal seals is about 55 years.

More Info: en.wikipedia.org