The South American fur seal (Arctocephalus australis)
The South American fur seal (Arctocephalus australis) breeds on the coasts of Peru, Chile, the Falkland Islands, Argentina, Uruguay and Brazil. The total population is around 250,000. However, population counts are sparse and outdated. Although Uruguay has long been considered to be the largest population of South American fur seals, recent census data indicates that the largest breeding population of A. a. australis (that breeds in Chile, the Falkland Islands, Argentina, Uruguay) are at the Falkland Islands (estimated pup abundance ~36,000) followed by Uruguay (pup abundance ~31,000). The population of South American fur seals in 1999 was estimated at 390,000, a drop from a 1987 estimate of 500,000 - however a paucity of population data, combined with inconsistent census methods, makes it difficult to interpret global population trends.
Arctophoca australis is known by different names, including:
- South American fur seal, southern fur seal, fur sea lion: obviously "fur seal" and "fur" allude to the quality of the animal's fur, which was highly prized in times when it was widely caught.
- Two-furred sea lion, two-furred otaria: also due to the characteristic of its skin, which has two superimposed "layers" or levels of fur, of different colours
- Sea bear: possibly less common, but consistent with the scientific name.
Description
South American fur seals have a dark grey or brown coat of fur. Adult males are much larger than females, with thicker necks and larger shoulders. Males also develop manes of longer guard hairs on their neck and shoulders. Size of the seals varies based on region, but on average, adult males measure up to 2 m long and weigh 150–200 kg and females measure up to 1.5 m long and weigh 30–60 kg. Newborns are 60 to 65 cm and 3.5 to 5.5 kg.
Distribution and habitat
The South American fur seal is found on neotropical ocean coasts from the Paracas Peninsula of southern Peru south to Cape Horn on the Pacific coast, and northward to southern Brazil on the Atlantic coast. They are also found on the Falkland Islands, Staten Island, and Escondida Island. A. australis seals prefer rocky shores and islands, particularly those with steep slopes. They have been found in sea caves in Peru, where some climb up to 15 m to find a spot to rest. There have been isolated records from continental Ecuador, the Galápagos Islands, and the Gorgona Island (Colombia). Anatomical information for the southern fur seals, Arctocephalus spp., is scant. In addition, little is known about the foraging ecology of South American fur seals. Recent tracking studies reveal that South American fur seals breeding at the Falkland Islands use a vast area of the Patagonian Shelf.
Life history
Arctocephalus australis prefer rocky shores and are able to traverse fairly steep climbs to reach their resting places. They often rest in caves, trying to hide from the heat of the day.
Quantity
On all coasts, the Arctocephalus australis gracilis has been targeted by hunters for centuries. On the coast of Peru, in the 1940s, only 40 seals remained. Only since then have laws prohibiting hunting allowed the population to grow back to 20,000. There are 20,000 Arctocephalus australis on the Chilean coast and 3,000 on the Argentinean coast. In the Falkland Islands, there are 15,000.
The largest population is in Uruguay, where colonies of Arctocephalus australis number 200,000 animals. It is the only country where limited hunting of Arctocephalus australis is currently permitted. In all other South American countries it is strictly protected. In general, the species is not threatened with extinction at present.
Subspecies
Two subspecies are currently recognised:
- Arctocephalus australis australis - Falkland Islands;
- Arctocephalus australis gracilis - South America.
The New Zealand fur seal is sometimes considered a subspecies of A. australis.
