Juan Fernández fur seal  (Arctocephalus philippii)

Remarkably, the Juan Fernández fur seal was considered extinct until it was happily rediscovered in 1965, although it nevertheless remains rare (4). Like most fur seals, this species has an elongated, slender body and a long, pointed snout and flippers (2) (5). 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 (6). 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) (6). The necks and fore-flippers of the males are usually scarred from fighting (4). 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 (6).

Breeding occurs on isolated rocks and islets of the Juan Fernández Archipelago and possibly San Félix / San Ambrosio island groups off the Chilean coast (2) (4). Ten to fifteen adult and juvenile males have also been seen during the autumn and winter at Punta San Juan on the Chilean mainland (4).

When ashore, these fur seals are usually found on rocky and volcanic shorelines with boulders, cliffs, overhangs, and caves (2) (6). There is a tendency to use caves or recesses, and individuals have been observed up to 25 metres from a cave entrance. Although these seals are often seen in the shallows of surrounding waters, adults generally forage for food in deeper water (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 (2). 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 (6). Thus, gestation takes a little under one year. Females give birth to a single pup, which they then nurse on land (2). After around 11 days after birth, females leave their pups to feed at sea, and for the next seven to ten months, undergo long foraging trips of about 12 days in length, returning to nurse the pup for an average of five days at a time (2) (4). The length of these feeding trips is exceptionally long for a fur seal, and leads to some of the longest intervals without suckling for any mammal (2) (4)!

The diet includes at least five varieties of squid, and there are reports that these fur seals also feed on various fishes and lobster (6). Sharks and killer whales are known to prey on Juan Fernández fur seals (4).

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 (4). When the species was rediscovered in 1965, just 200 individuals survived, but with conservation the population has since steadily increased to more than an estimated 12,000 (7). 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 (4). 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 (4). This measure appears to have been successful as, since then, there has been an annual population increase of 16 to 17%, in spite of occasional illegal hunting (5).

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