Juan Fernández fur seal (Arctocephalus philippii)

Synonyms: Arctophoca philippii
  
French: Arctocéphale De Juan Fernandez
Spanish: Oso Marino De Chile
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderCarnivora
FamilyOtariidae
GenusArctocephalus (1)
SizeMale length: 150 – 210 cm (2)
Female length: 140 - 150 cm (2)
Male weight: 140 – 159 kg (2)
Female weight: 50 kg (2)

Classified as Near Threatened (NT) on the IUCN Red List (1), and listed on Appendix II of CITES (3).

Remarkably, the Juan Fernández fur seal was considered extinct until it was happily rediscovered in 1965, although it nevertheless remains rare (2). Like most fur seals, this species has an elongated, slender body and a long, pointed snout and flippers (2) (4). Adult males have a particularly long muzzle that may be slightly down-curved at the tip, and which ends in a large, bulbous, fleshy nose, creating a shark-like silhouette (2). Adult males also develop thicker and more muscular necks, surrounded by a mane of long, coarse, dark hair with silver tips, giving the mane a frosted appearance (2). The necks and fore-flippers of the males are usually scarred from fighting (5). The back and belly are dark, blackish-brown in males, while the crown down to the ears and nape to the shoulders sometimes appear silvery-grey, against a darker throat and neck. Adult females are grey-brown to dark brown above, and variably paler below, especially on the chest and underside of the neck, which can be creamy grey, and there may be areas of lighter colour on the face. Both sexes have whitish-cream whiskers (2).

Breeding is restricted the Juan Fernández Archipelago, and the islands of San Felix and San Ambrosio, off the coast of Chile (6), and the seal can be found in an incompletely known area of surrounding waters (2).

When ashore, these fur seals are usually found on rocky and volcanic shorelines with boulders, cliffs, overhangs, and caves (2).

These social animals live in large, male-dominated groups in which breeding behaviour is highly territorial. Males hold territories both on land and in the water, with females within each territory mating with the resident male. As such, males will often fight fiercely to maintain these territories (6). Breeding occurs from mid-November until the end of January, immediately after pupping, with most pups from the preceding breeding season being born from late November to early December (2). Thus, gestation takes a little under one year. Females give birth to a single pup each year, which they then nurse on land, for a period of about 8 to 12 months (7). Soon after the birth of the pup, the female will mate again, before departing to sea to feed, returning from time to time to suckle her pup. A female returning from a feeding trip comes to the beach where she left her pup, and calls for it with a characteristic call. The pup answers with its own call, which is recognised by the mother, and their identity is confirmed by smelling the pup (6).

The diet includes at least five varieties of squid, and there are reports that these fur seals also feed on various fishes and lobster (2). Sharks and killer whales are known to prey on Juan Fernández fur seals (5).

Once abundant, this fur seal was heavily exploited by commercial sealers from the 17th to the 19th centuries for its pelt, blubber, meat and oil, and by the beginning of the 20th century it was believed to be extinct (5). When the species was rediscovered in 1966, just 200 individuals survived (2), but the population has since steadily increased (8). However, despite being protected by the Chilean government, the Juan Fernandez fur seal is sometimes poached illegally for lobster bait, fur and meat (4) (5). Occasional reports also exist of the seal becoming entangled in fishing nets and plastic waste (5). There is an additional concern that the seal may have to compete with fisheries for its food, and due to its limited size, the population is vulnerable and may suffer from a lack of genetic diversity (4) (5).

After rediscovery, the species was given total protection by national Chilean legislation in 1978 (5). This measure appears to have been successful as, since then, there has been an annual population increase of 16 to 17 percent, in spite of occasional illegal hunting (4).

For more information on the Juan Fernández fur seal, other seal species and their conservation see:

 

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (November, 2008)
    http://www.iucnredlist.org
  2. Jefferson, T.A., Leatherwood, S. and Webber, M.A. (1993) FAO Species Identification Guide. Marine Mammals of the World. Food and Agriculture Organization of the United Nations, Rome.
  3. CITES (November, 2006)
    http://www.cites.org
  4. Jaap’s Marine Mammals Page (November, 2006)
    http://ourworld.compuserve.com/Homepages/jaap/furseals.htm#juanfernandez
  5. Seal Conservation Society (November, 2006)
    http://www.pinnipeds.org/species/juanfur.htm
  6. Macdonald, D. (2001) The New Encylopedia of Mammals. Oxford University Press, Oxford.
  7. Arnould, J.P.Y. (2002) Southern Fur Seals. In: Perrin, W.F., Würsig, B. and Thewissen, J.G.M. (Eds) Encyclopedia of Marine Mammals. Academic Press, London.
  8. International Marine Mammal Association Inc. (November, 2006)
    http://www.imma.org/pinnipeds/juanfernandezfs.htm