South American Sea Lion

The South American sea lion was classified as Otaria flavescens by George Shaw in 1800 and as Otaria byronia by Henri Marie Ducrotay de Blainville in 1820. The two nomenclatures were historically used interchangeably, but O. flavescens has become the preferred name. The species is also known by the common name "southern sea lion", although it is not preferred since the Australian sea lion and New Zealand sea lion also range in the Southern Hemisphere. Locally, it is known by several names, including león marino (sea lion) and lobo marino (sea wolf).

The South American sea lion is found along the coasts and offshore islands of South America, from Peru south to Cape Horn and then north to southern Brazil. However, the movement ecology of South American sea lions remains poorly understood, although biologging studies in recent years have advanced our understanding of their at-sea movements at some breeding locations. There is no evidence of a winter migration of sea lions from the Falkland Islands. South American sea lions breed on beaches made of sand, gravel, rocks, or pebbles. They can also be seen on flat, rocky cliffs with tidepools. Sea lion colonies tend to be small and scattered, especially on rocky beaches. The colonies make spaces between each individual when the weather is warm and sunny. They have even been observed preying on penguins, pelicans, and female and young South American fur seals. South American sea lions may forage at the ocean floor for slow-moving prey or hunt schooling prey in groups, depending on the area. When captured, the prey is shaken violently and torn apart. The sea lions themselves are preyed on by orcas and sharks; at Peninsula Valdes, orcas will beach themselves and grab sea lions near shore.

Mating occurs between December and February. Males arrive first to establish and defend territories. Estrus in females usually begins six days after the birth of a pup and soon after the copulations start with a peak in January. At Peninsula Valdes, males first defend territories, but then switch to defending females when they arrive. A male aggressively herds females in his territory—even chasing after those that escape—and defends them from both neighbors and intruders. At Isla de Lobos, males near the surf have a similar breeding system, defending females and "floating" territories, while those further inland strictly defend territories around tide pools which attract females. The number of actual fights between males depends on the number of females in heat. The earlier a male arrives at the site, the longer his tenure will be and the more copulations he will achieve. Males are usually able to keep around three females in their harems, but some have as many as 18. ]] During the breeding season, males that fail to secure territories and harems, most often subadults, will cause group raids in an attempt to change the status quo and gain access to the females. Group raids are more common on sandy beaches than rocky ones. These raids cause chaos in the breeding harems, often splitting mothers from their young. The resident males try to fight off the raiders and keep all the females in their territorial boundaries. Raiders are often unsuccessful in securing a female, but some are able to capture some females or even stay in the breeding area with one or more females. Sometimes, an invading male abducts pups, possibly as an attempt to control the females. They also take pups as substitutes for mature females. Subadults herd their captured pups and prevent them from escaping, much like adult males do to females. A pup may be mounted by its abductor, but intromission does not occur. While abducting pups does not give males immediate reproductive benefits, these males may gain experience in controlling females. Pups are sometimes severely injured or killed during abductions. Despite being mostly a harem-territorial species, one population in Peru has been recorded having a lek-like breeding system. Here, with its longer ratio of males in comparison to females, the males cluster together and display and try to attract females while allowing them to move freely. The warmer climate also makes the females move constantly to the water, further making the traditional mating system difficult to maintain. The group raids that exist in temperate populations are virtually non-existent here. Sea lion mothers remain with their newborn pups for nearly a week before making a routine of taking three-day foraging trips and coming back to nurse the pups. Pups first enter the water at about four weeks and are weaned at about 12 months. This is normally when the mother gives birth to a new pup. Pups gradually spend more time in the nearshore surf and develop swimming skills.

The Moche people of ancient Peru worshipped the sea and its animals. They often depicted South American sea lions in their art. Two statues of this species are the symbol of the city of Mar del Plata. Indigenous peoples of South America exploited this species for millennia and by Europeans around the 16th century. The hunting has since gone down and the species is no longer threatened. The species is protected in most of its range. Numerous reserves and protected areas at rookeries and haul-out sites exist for the sea lions. Despite this, protection regulations are not effectively enforced in much of animals' range. They still are killed due to their habits of stealing fish and damaging fishing nets.