At three years of age, female juveniles can become pregnant and are then called cows. Male juveniles, though, are too small to become bulls. For the next three to five years, they are called sub-adults. They gradually get bigger. On land, they practice jousting with other sub-adults. Eventually, they get big enough to try to hold a territory during the breeding period.

Seals can live for up to 15 to 20 years.