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South American Sea Lion


Otaria redirects here. For the continent in , see Otaria.

The South American Sea Lion , also called the Southern Sea Lion and the Patagonian Sea Lion, is a sea lion found on the Chilean, Peruvian, Uruguayan and Argentine coasts. Its scientific name was subject to controversy, with some taxonomists referring to it as Otaria flavescens and other referring to it as Otaria byronia. The former eventually won out. Locally, it is known by several names though the most common ones are "lobo marino" (sea wolf) and "leon marino" (sea lion).

Physical description

The South American sea lion is perhaps the archetypal sea lion in appearance. Males have a very large head with a well developed mane making them the most lionesque of the eared seals. They are twice the weight of females. Both males and females are orange-coloured with upturned snouts. The manes on males are lighter than females, and female fur on the head and neck is lighter than that of males. Pups are born black or dark brown and molt into a more chocolate colour. The South American Sea Lion's size and weight can vary quite a lot. Adult males can grow over 2.73 m (9 ft) and weigh up to 350 kg (770 lb). Adult females grow up to 1.8–2 m and weigh about half the weight of the males, around 150 kg (330 lb). These sea lions are the most sexually dimorphic of the five sea lion species.

Range and habitat

As its name suggests, the South American sea lion is found along the coast and offshore islands of South America. The endpoints of its range are Zorritos in northern Peru and Ilha dos Lobos in southern Brazil. Notable breeding colonies include Lobos Island, Uruguay; Peninsula Valdes, Argentina; Beagle Channel and the Falkland Islands.

South American sea lions prefer to breed on beaches made of sand, but will breed on gravel, rocky or pebble beaches as well. They can also be seen on flat rocky cliffs with tidepools. Sea lion colonies are more scattered on rocky beaches than sand, gravel or pebble beaches. The colonies make spaces between each individual when it is warm and sunny. They can also be found in marinas and wharves but don't breed there.

Foraging

South American sea lions feed on a variety of fish including Argentine hake and anchovies. They also eat cephalopods, such as shortfin squid, Patagonian squid and octopus. They have even been observed preying on penguins, pelicans and young South American Fur Seals. South American sea lions normally hunt in shallow waters less than five miles from shore. They often forage at the ocean floor for slow moving prey but they will also hunt schooling prey in groups. When captured, the prey is shaken violently and torn apart. The sea lions themselves are preyed on by orcas and sharks.

Reproduction

Mating occurs between August and December and the pups are born between December and February. Breeding groups can consist of up to 18 females with one to several males. Males maintain their boundaries by barking, roaring and other vocalizations. The males herd the females into their territories and prevent them from leaving until mating is over. The number of actual fights between males depends on the number of females in heat.

During the breeding season, group raids will happen and are mostly caused by gangs of subadult males attempting to mate with the females. These raids cause chaos in the breeding harem, often splitting mothers from their young. The resident males are unable to fight off all the raiders and keep all the females in their territorial boundaries. Nevertheless subadult males are often unsuccessful securing a female. Sometimes an invading male will abduct pups possibly as an attempt to control the females. Pups are often severely injured or killed when this happens.

Sea lion mothers have a routine of taking trips back into the sea for food and come back to nurse the pups. Pups first enter the water at about 4 weeks and are weaned at about 12 months. This is normally when the mother gives birth to a new pup.

Human interactions

The Moche people of ancient Peru worshipped the sea and its animals. They often depicted South American sea lions in their art.Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueologico Rafael Larco Herrera. New York: Thames and Hudson, 1997. A statue of this species is a symbol of Mar del Plata.

South American sea lions were greatly hunted in the 19th and 20th centuries. The hunting has since gone down and the species is no longer threatened and is protected in most of its range. The population estimate is 265,000 animals. They are increasing in Argentina and Chile but are declining in the Falkland Islands and Uruguay. They still are killed due the sea lions' habits of stealing fish and damaging fishing nets. Sea lions in the ports of Mar del Plata have been found with toxic chemicals and heavy metals in their system.

References

Rodriguez, D., R. Bastida. 1993. The southern sea lion, Otaria byronia or Otaria flavescens?. Marine Mammal Science, 9(4): 372-381.

Campagna, C., B. Le Boeuf. 1988. Reproductive behavior of southern sea lions. Behaviour, 104(3-4): 233-261.

http://www.sealionsearch-rescue.com/facts.html

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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article South American Sea Lion


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