The species, as is often the case in sea lions, has a pronounced sexual dimorphism. Males have a mane, which is one of the reasons why they are called “sea lions”.
Environment and behavior
This species is rather sedentary and polygamous. The harem usually consists of one male for every 4 to 10 females. The male arrives on the beach about two weeks before the females. He defends his territory in two different ways, depending on the layout of the area. Either the beach has small alcoves, and the male prevents females from leaving, or other males from entering, by means of vocalizations, postures or aggressive behavior. Or the beach is a long strip of land/sand, and the male keeps the females away from the water by pacing up and down the beach. Two or three days after their arrival, the females give birth to their pups, which they have carried for a year. Six days after giving birth, they ovulate and mate again. Then they begin to alternate, spending 1 to 4 days at sea to hunt and 2 days ashore to nurse, until the pup is between 8 and 10 months old.
Killer whales, sharks and leopard seals
After several hundred years of being hunted for its fur and oil, the South American sea lion population has greatly decreased. Today, voluntary culling by fishermen and by-catching in trawler nets continue to drastically reduce the number of sea lions, especially around the Falkland Islands, where intensive fishing is practiced.