Juan Fernández Fur Seal
(Arctocephalus philippii)
| Distribution and Numbers Considered to be extinct until it was rediscovered in 1965, the Juan Fernández fur seal occupies isolated rocks and islets on the Juan Fernández and San Félix / San Ambrosio island groups off the Chilean coast. Ten to fifteen adult and juvenile males have also been seen hauling out during the autumn and winter at Punta San Juan on the Chilean mainland, individuals also possibly wandering as far north as the Peruvian coast. The total population is currently estimated at 12,000. Status According to the records of the first sailors to encounter these seals at the Juan Fernández Islands, they were very abundant and numbered possibly in the millions. However the species was very heavily exploited for its pelt, blubber, meat and oil by commercial sealers from the 17th to 19th centuries and by the beginning of the 20th century it was believed to be extinct. |
 Photo: Daryl Boness, Smithsonian Institution |
| After rediscovery, the species was given total protection by national
Chilean legislation in 1978. The species is listed as Vulnerable on the IUCN Red List, due to
its limited population size and the fact that the species' low genetic diversity may cause
problems, and is also listed as an Appendix
II species under CITES. The IUCN/SSC Specialist group has
recommended that research be carried out into the diet of the species in order to
determine any potential competition with fisheries. There have been reports of fishermen
on Alejandro Selkirk Island using the seal as bait, as well as for food and as a barter
commodity. There have been occasional reports of entanglement in fishing nets, while the
occurrence of seals with plastic wrapped around their necks has often been reported. |
 Photo: Daryl Boness, Smithsonian Institution |
Lifestyle There has not been a great deal of research carried out into the lifestyle and habits of the Juan Fernández fur seal. However a few key studies have recently shown that various interesting differences exist between the breeding habits of Juan Fernández fur seals and other fur seals due to the high temperatures and the nature of the species' habitat. Pupping usually occurs in November-December and breeding normally takes place at rocky sites, the adult males fighting for territory, not only on land as is typical for fur seals, but also on the shoreline and in the water. The use of completely aquatic territories is an important reproductive strategy in this species that has yet to be seen in other eared seals. Most females move down to the shoreline and into the water in order to cool down during the hottest parts of the day. Mating, which usually takes place about a week after the pup is born, can also occur at this time. Males on land often abandon their territories for an average of 45 minutes in order to enter the sea and cool down. |
| The mother leaves her pup in order to feed at sea about 11
days after giving birth, longer than for other fur seal species, and for the next 7-10
months she alternates periods of an average of 5 days nursing her pup on land with feeding
trips lasting an average of 12 days. The lengths of these feeding trips are exceptionally
long for a fur seal. The fur of the Juan Fernández fur seal is black-brown, lighter on
the front. The necks and fore-flippers of the males are usually scarred from fighting. The
Juan Fernández fur seal has a fairly narrow range of prey species, probably due more to
availability rather than specialisation, their main prey being myctophid and squid. The
individuals of this species do not dive very deeply, one study showing that females dive
to an average of only 12.3m while feeding. Sharks and killer whales are known to prey on
Juan Fernández fur seals. Statistics Adult males measure 1.5-2.1m in length and weigh about 140kg, while adult females normally measure about 1.4m in length and weigh about 50kg. Pups are born 65-70cm in length and weigh 6-7kg, male pups being slightly longer and heavier than female pups. It is thought that males may live over 13 years while females may live up to 23 years. |
 Photo: Daryl Boness, Smithsonian Institution |
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