While the bulls are establishing and holding territories in the colonies, the cows start to come ashore and have their pups. Cows weigh about 60 to 80 kg. About 9 cows will gather in the territory of each bull. Each cow gives birth to a single pup. The cows suckle their pups, providing them with a rich, creamy milk. A week after giving birth, the cow will breed with the bull. She will give birth again 12 months later.

As her pup grows, the cow has to leave it at the colony while she goes to catch more food. Then she returns to the colony to  supply milk to the pup. At first, she will be away for just a few hours, then a few days. When the pup is one to two months old, the cow can leave it for a week or more.