Neotropical ocean coasts; ranges from southern Peru (Paracas Peninsula) south to Cape Horn on the Pacific side, and northward to southern Brazil on the Atlantic side. Also found in the Falkland Islands, Staten Island, and Escondida Island. There are two subspecies, based on size and range. Arctocephalus australis gracilis, the more widespread of the two, occurs throughout the entire range along the mainland. The smaller subspecies, Arctocephalus australis australis, inhabits the Falkland Islands. Recently, a population on South Georgia Island was determined to be A. australis australis (Reeves, et al. 1992, Daneri, et al. 1997, Nowak 1999).

Biogeographic Regions: neotropical (Native ); atlantic ocean (Native ); pacific ocean (Native )

Adult males reach an average length of 1.9 meters and mass of 150 – 200 kg. Their fur is blackish gray, with a mane of long guard hairs on the shoulder and neck area. The build of the male is proportionally broader in the shoulders than the female. Adult females average about 1.4 meters in length and a mass of 30 – 60 kg. Female and subadult fur is grayish black on the back and lighter on the ventral side. Newborn pups are all black. In general, these seals have a stocky build with a flat-topped, pointed muzzle and creamy white vibrissae. Ear pinnae are prominent. Dental formula 3/2, 1/1, 6/5. (Reeves, et al. 1992, Jefferson, et al. 1994, Nowak 1999)

Range mass: 30 to 200 kg.

Average mass: 110 kg.

Range length: 1.4 to 1.9 m.

• Terrestrial
• Marine

Arctocephalus australis apparently prefer rocky shores and islands, especially those with lots of vertical slope. This provides shady areas for them to escape the heat of the sun. During a given day there may be movement from drier rocks to areas close to the sea or in tide pools. They have been found in sea caves in Peru, where some climb up to 15 meters to find a spot to rest. Not much is known about their movements at sea, but a recent study with satellite telemetry has discovered that females will travel 15 to 200 km when foraging at sea. (Nowak 1999, Falklands Conservation 2000)

Average depth: 29 m.

Habitat Regions: temperate ; saltwater or marine

Aquatic Biomes: coastal

The diet consists of anchovies, sardines, and mackerel, along with cephalopods, crustaceans, bivalve mollusks, and gastropods. Arctocephalus australis individuals usually forage at night and will dive for 3 minutes to an average depth of 29 meters, but will reach a maximum time of 7 minutes and 170 meters in pursuit of food. Numbers of anchovy can fluctuate abruptly in the Pacific Ocean, where El Nino events occur every 2 – 7 years. This will affect reproductive success of females. (Reeves, et al. 1992 & Majluf 1992)

Animal Foods: fish; mollusks; aquatic crustaceans

Primary Diet: carnivore (Piscivore , Eats non-insect arthropods)

South American fur seals are important members of the ecosystems in which they live. They are important predators on fish species and other marine organisms, and are preyed on by the largest predators in these oceans, great white sharks(Carcharodon carcharias) and orcas (Orcinus orca).

No information was available on anti-predator adaptations. South American fur seals are preyed on by large sharks, such as great white sharks (Carcharodon carcharias), orcas (Orcinus orca), South American sea lions (Otaria byronia), and by humans. Their large size will protect them from many, smaller predators.

(Reeves, et al. 1992 & Couturier 1996)

Known Predators:

• South American sea lions (Otaria flavescens)
• sharks (Chondrichthyes)
• killer whales (Orcinus orca)
• humans (Homo sapiens)

South American fur seals have an estimated lifespan of 25 to 30 years for females and 15 to 20 years for males. (Lima & Paez 1997)

Typical lifespan

Status: wild: 15 to 30 years.

Range lifespan

Status: captivity: female: 30.6, male: 20 (high) years.

In the austral spring (October – December) bulls establish breeding territories, approximately 50 square meters in area. Although they try to herd females and create harems, females typically move about freely. Dominant males are more successful at mating with more females. Non-breeding males are pushed to a separate part of the rookery, closer to the ocean. There, the younger males will engage in mock territory battles.

Mating System: polygynous

For South American fur seals, sexual maturity is reached at 3 years for females and 7 years for males. Females begin estrus usually 6 to 8 days after they give birth and, though all will mate, only about 15% will give birth the next year if they are nursing a pup. After mating, implantation is delayed for 4 months. Total gestation time averages 11.75 months. Litter size is limited to one pup. Reproduction is synchronous in rookeries, with a peak birthing period at a time of peak food availability. If rearing takes longer than a year, a second pup will be born, resulting in competition for the mother’s milk. After birth, the pup is nursed for 7 months to 3 years, depending on environmental conditions. Lactation period may vary and can overlap with pregnancy, resulting in energetic costs that are paid by smaller young being born. It can also result in successful births only occuring every few years, rather than yearly. This phenomenon is unique for Arctocephalus australis among otariids. In addition, an Uruguayan study showed a significant difference in pregnancy rates in Arctocephalus australis from year to year, indicating that both environmental and demographic stochasticity play a role in population dynamics. Pups are born throughout November and December along the Uruguayan coast, a bit earlier in Peru. Pups’ average weight is 3-5 kg. Studies have shown that females that lactate during pregnancy give birth to smaller young. Growth rates of young are slow, varying between 0.05 – 0.09 kg/per day. The average pup length at birth is 60-65 cm for males, 57-60 cm for females. Females reach full size in ten years. Both male and female pups are born with a dark coat of fur but, as they mature, females develop lighter coloration ventrally. Mortality of pups can be caused by maternal aggression during times of movement to or from the water and is considered to be higher than in other species of otariids (10 – 48%). Death can also be caused by aggressive males or by males of South American sea lions, Otaria byronia. However, a study in Uruguay showed South American fur seals to have an overall high survival rate for young adults. (Trillmich 1990, Harcourt 1992, Majluf 1992, Harcourt 1993, Nowak 1999)

Breeding season: Mating and birthing occurs from October through January.

Average number of offspring: 1.

Average gestation period: 11.75 months.

Range weaning age: 7 to 36 months.

Average weaning age: 12 months.

Average age at sexual or reproductive maturity (female): 3 years.

Average age at sexual or reproductive maturity (male): 7 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; delayed implantation

Average birth mass: 4250 g.

Average gestation period: 236 days.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)

Sex: male: 2556 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 1095 days.

Pup rearing is done by the mother, with no help from the male. After birth, the mother will remain with the pup for 5 to 10 days before leaving to forage. Mothers will alternate between average foraging trips of 4.6 days and nursing their young for 1.3 days.  (Majluf 1992, Reeves, et al. 1992, Jefferson, et al. 1994, Lima and Paez 1995, Couturier 1996, Nowak 1999)

Parental Investment: precocial ; female parental care

The population of South American fur seals in 1999 was estimated at 390,000, a drop from a 1987 estimation of 500,000. Although overall species numbers are healthy, the downward trend is causing some concern. Uruguay has the largest numbers of seals along its coast, numbering over 200,000. Peru’s number dropped to only 40 in the 1940’s, but subsequent protection has brought the numbers back up to about 20,000 by the 1980s. Because of the El Nino events and general overfishing along the Pacific coast of South America, the population in the Pacific is not recovering as quickly as it could. Presently, Peru has had a problem with fishermen illegally killing South American fur seals, claiming that the seals interfere with fishing operations and diminish the anchovy numbers. In the Falkland Islands, where commercial hunting greatly reduced their numbers, the population now contains about 15,000 seals. There are approximately 40,000 seals in Chile and 3,000 in Argentina. Arctocephalus australis is on appendix 2 of the CITIES. (Reeves, et al. 1992, Couturier 1996, Jefferson, et al. 1994)

CITES: appendix ii

IUCN Red List of Threatened Species: least concern

Fishermen may complain that these fur seals compete with them for valuable fish, such as mackerel and sardines, though their true impact on fisheries is likely to be negligible.

South American fur seals have been hunted for centuries, both by indigenous peoples and by whalers. Early peoples in the area of Tierra del Fuego, as well as in Uruguay and Peru, used the seal for meat and clothing. Commercial hunting of these seals began in Uruguay as early as the 1500s, mainly for their skins and oil. The oil was used for lighting and later as a medicinal for tuberculosis. Hunting pressure was unregulated until the 1940s, when a population decline in Uruguay was evident. Since then, take has had an annual limit, which now is about 7,000 – 12,000 seals, limited to young males. In Peru, commercial hunting of these fur seals continued until 1959, when it was prohibited. In Chile and Argentina, the seals were hunted and used for bait to catch king crab. Today, commercial hunting is only done in Uruguay. (Reeves, et al. 1992, Jefferson, et al. 1994)

Positive Impacts: ecotourism ; source of medicine or drug ; research and education