Mundo Azul

South American sea lion, Punta San Juan (© Jean Pichon / Mundo Azul)

Family: Otariidae

Specie: Otaria flavescens (Shaw, 1800) or Otaria byronia (de Blainville1820)

Common names:

English: South American Sea lion

French: Lion de mer d'Amérique du Sud

German: Südamerikanischer Seelöwe

Peru: lobo chusco

Uruguay and Argentina: León marino sudamericano, lobo marino de un pelo, lobo ordinario, lobo común, lobo grueso;

Chile: lobo chusco o león marino austral

Swimming with lions video

Sea lions in Bayovar

South American Sea lion colony, Morro Quemado, Reserva Nacional de Paracas (© Jean Pichon / Mundo Azul)

South American Sea lions have a rounded snout, and their pelage is short and coarse. Adult Sea lions have a dark, brown back and yellowish-brown front, the males having a lighter colored mane and the females having lighter colored fur on the head and neck.

There is some variation in body size over the species' range. Adult male South American Sea lions measure an average of 2.6m in length and weigh around 300kg, while adult females measure an average of 1.8-2m in length and weigh around 150kg. Male pups are born weighing an average of 13.7kg and measuring 82cm in length. Female pups are smaller, weighing an average of 12.3kg and measuring 79cm. Females reach sexual maturity at 4-6 years, males at 5-6 years, although males only first achieve territorial status at 9-10 years. South American Sea lions live for about 20 years

Distribution

Distribution area of South American Sea lions

The species is distributed along the coasts of South America and the Falkland Islands. Along the Pacific Coast, reproductive colonies can be found from Isla Foca, Peru, southwards to Tierra del Fuego, Chile. and in the Atlantic from Isla de Los Estados (54°45'S) in Argentina to Recife dos Tôrres (29°21'S) in Brazil. Sometimes specimens can be observed along the coast of Bahía in Brazil and in the Pacific along the coast of Ecuador, Colombia and Panama, as well as on the Galapagos Islands and Tahiti.

Population size

The total population size is estimated at around 260,000 specimens, including:

Peru: approximately 60,000
Chile: 90,000
Argentina: 90,000
Uruguay: 12,000 - 15,000
And a few hundred in Brazil.

The populations in Uruguay and on the Falkland Islands show a rapid decline. On the Falkland Islands, the population declined from 400,000 specimens in 1930 to less than 6,000 in 1995.

In Argentina, populations are increasing at around 3% annual (Seal Conservation Society 2000).

In Peru, around 80% of the population of 144,000 specimens died during the El Niño event 1997/98 leaving around 28,000 alive. Until now, the population has only recuperated to an estimated 60,000.

Ecology

On land, their distribution is limited by the level of isolation, or in other words, by the level of disturbance that occurs. Generally, the Sea lions concentrate on inaccessible areas like islands or at the base of coastal cliffs. Southern Sea lions prefer sandy beaches or pebble beaches.

South American sea lion males start arriving at the breeding beaches in December in order to compete for territorial space. Each territory in the large rookeries that develop will contain an average of 3-6 females. Males who are unable to establish territories often attack undefended females and pups, and also sometimes attempt to mount, and in doing so kill, female and young South American fur seals.

Most pups are born about 3 days after the mother's arrival at the rookery, from mid-December to the end of January (from the end of January to the end of February in northern Chile). The pup is born with a black coat that will turn brown to reddish-brown after a few months. The mother usually mates about 7 days after giving birth, and then leaves her pup in order to feed at sea. This begins a cycle, lasting 6-12 months, in which the mother forages at sea for about 3 days and then nurses her pup on shore for about 2 days. Pups enter the water at about 3-4 weeks for the first time and are good swimmers by the time they are 2 months old.