Cape fur seal reproduction explained

Mating a few days after birth; females almost constantly pregnant
Claudia Reiter
Ocean Conservation Namibia reports that there are around 40 breeding colonies of Cape fur seals on the coast of southern Africa.
Females usually have their first young when they are 5 or 6 years old. While young males can reach sexual maturity at about the same age, it takes 10 to 12 years for them to reach full size in order to successfully defend a breeding territory against other bulls.
"Pelican Point and Cape Cross are both breeding colonies and we often see the bulls fighting over the females," the organisation said.
Based on research, Cape fur seals give birth to a single pup between the end of November and December. "She will suckle her pup until she has the next one exactly a year later." The seal mothers swim into the ocean to look for food and leave their young behind with other newborns. These so-called "nursery groups" are supervised by other mothers who happen to be on the coast, and they defend all newborns from birds, jackals and other potential predators.
"Mothers may need to be separated from their babies for several days until they have eaten enough to return to their babies."
Furthermore, the research found that bulls begin mating with a new mother just a few days after birth - meaning that the females are almost always pregnant.
"The bulls stay at sea most of the year, where they hunt and rest. They usually return to the coast in October and November to stake out their territory and drive as many females as possible into so-called 'harems'. A large alpha bull therefore takes up to 50 or 60 female seals for itself, hindering other bulls from mating with them. The bulls live on their blubber reserves during this time and can lose up to a third of their body weight before returning to the sea. They spend the entire breeding season, from October to January, defending their territory and harem, with no time to go out to sea and hunt.
The bulls return to the sea once the mating season is over.
Cape fur seal pups are born between November and January.
According the the research, in the first few days they stay with their mother until she goes looking for food. When she returns, mother and baby find each other among thousands of other young animals through smells, calls and barks. Seal milk is very rich and nutritious, so the young animal can stay behind for a few days without starving. Seal pups start swimming after a few weeks, but it takes a few months before they can catch fish themselves. They remain dependent on their mothers’ milk until the next newborn replaces them.