Juan Fernández Fur Seal

Sharks and killer whales are known to attack other species of this genus although no specific information was available for A. philippii. They are fast and maneuverable swimmers and can seek refuge on land from these aquatic predators.

Known Predators:

• sharks (Chondrichthyes)
• killer whales (Orcinus orca)

The body is similar to that of most fur seals, slender and elongated, with males ranging from 150 to 200 cm, and females at about 140 cm in length. Weight of males is about 140 kg, and females weigh about 50 kg. All species of Arctocephalus have similar coloration. The under fur and bases of flippers are described as rich and chestnut brown in color. Males have a thick mane of long hair that is dark with white tips, giving the mane a frosted appearance. Males have a long pointed nose which is distinctive. Females have a noticeable grey-brown to dark brown coloration on the back but are paler below, especially on the chest and underside of the neck.

Range mass: 50 to 140 kg.

Range length: 140 to 200 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger; sexes colored or patterned differently

The longevity of A. philippii is unknown but may be similar to A. gazella, in which expected life span is 13 years for males, with females typically living about 23 years.

Juan Fernandez fur seals are usually found hauled out on rocks at the base of cliffs or ledges. They also have the tendency to use caves or recesses while on shore and have been seen 25 meters from a cave entrance. This habit may have saved them from hunters, as many of the caves are inaccessible to humans. Individuals are often seen active in the shallows, but adults generally forage in deep water.

Habitat Regions: temperate ; saltwater or marine

Aquatic Biomes: coastal

Due to the decline and subsequent rise in population size, A. philippii has been used in a number of genetic studies.

A. philippii are very vocal with calls ranging from a bark, usually when an animal moves or is playing, to a high-pitched scream often aimed at the approach of an intruder. Individuals may use a guttural cough if threatened. Females with pups will make a prolonged bawl. The communication is seemingly complex. Communication also occurs through visual and tactile cues and perhaps chemical cues, such as pheromones.

Communication Channels: visual ; tactile ; acoustic ; chemical

Perception Channels: visual ; tactile ; acoustic ; chemical

During the late 17th century, A. philippii were abundant, with the population estimated as high as 4 million. After one century of heavy exploitation, they were believed to be extinct until 1965, when they were observed on Alejandro Selkirk Island. Since 1965 the population has increased dramatically, with the current population estimated at more than 12,000. Species of Arctocephalus are on Appendix 2 of CITES, and the IUCN classifies A. philippii as vulnerable.

CITES: appendix ii

IUCN Red List of Threatened Species: near threatened

There are no known adverse affects of Arctocephalus philippii on humans although the possibility of competition with commercial fisheries has been noted in conjunction with conservation efforts.

Juan Fernandez fur seals were used heavily by sealers in the late 1700s and early 1800s as a source of pelts, blubber, meat, and oil. Unfortunately this hunting lead to precipitous population declines and near extinction.

Positive Impacts: body parts are source of valuable material; research and education

Although no exact interactions are known it can be assumed that A. philippii would effect the populations of their aquatic prey, and that any stillbirths would help local waterfowl.

Juan Fernandez Fur Seals are reported to feed on cephalopods, such as squid, and on fish.

Animal Foods: fish; mollusks

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

Juan Fernandez fur seals are found today on the islands they were named for, off the coast of central Chile. It is suspected that they may also breed on the San Felix and San Ambrosio islands off northern Chile

Biogeographic Regions: neotropical ; pacific ocean

The breeding behavior is very territorial, with males holding aquatic and land territories. Males will often fight to maintain these territories. Females within each territory mate with the resident male. A. philippii are polygynous in their mating system.

Mating System: polygynous

Breeding in most fur seal and sea lion species occurs just after a female has given birth to a single pup from the preceding breeding season. In Juan Fernandez sea lions the peak pupping season is in late November and early December. Breeding occurs from November to January. Gestation is sligthtly less than one year.

Breeding interval: Juan Fernandez Fur Seals breed once yearly.

Breeding season: Mating occurs from November to December.

Average number of offspring: 1.

Average gestation period: 12 months.

Range weaning age: 7 to 10 months.

Range time to independence: 7 to 10 months.

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

Females give birth to a single pup and nurse on land. After a long initial post-natal suckling bout (averaging 11.3 days in length), females of A. philippii undergo long foraging trips (averaging 12.2 days in length), and this leads to some of the longest recorded intersuckling intervals for a mammal. Fat and energy content of milk is the highest of any member of the family Otariidae examined, allowing young to grow rapidly despite long periods of fasting.

Parental Investment: precocial ; female parental care

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).

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).

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).

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

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

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).

Juan Fernandez fur seal adults have whitish cream vibrissae and prominent, long ear pinnae. Adult males have a very long, pointed, flat muzzle that may be slightly down-curved at the very end, and which terminates in a large, bulbous, fleshy nose, with downward pointing nostrils. The large size of the nose creates a shark-like silhouette in bulls. The forehead is flat to slightly convex. Adult males develop a mane of long, coarse guard hairs. This area is also thickened and more muscular in bulls. Nearly all adult males are scarred, some heavily. In adult females, the muzzle is long and pointed, and the nose extends beyond the mouth somewhat. The nose is large, but not as bulbous as in adult males. In most aspects, females seem to be typical of other species of the genus. Adult males are dark blackish brown on the back and belly. The longer guard hairs of the mane are silver-tipped. The crown down to the ears, and nape to the shoutders sometimes appear silvergrey; the throat and neck are darker. 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. There may be areas of lighter colour on the face. The dental formula is I 3/2, C 1/1, PC 6/5. Can be confused with: Among other otariids, the South American Antarctic fur seal, and subantarctic fur seal, and the South American sea lion have distributions that normally bring them near to that of Juan Fernandez fur seals, but there is no evidence that any of the former 3 species has regularly occurred at the Juan Fernandez Archipelago, nor is there a record for the Juan Fernandez fur seal on the mainland of South America.

Adult males are estimated to be 1.5 to 2.1 m in length and weigh 140 to 159 kg. Adult females are estimated to be 1.4 to 1.5 m and 50 kg. Average lengths and weights for newborns are approximately 65 to 68 cm and 6.2 to 6.9 kg.

Breeding in this species is from mid-November to the end of January; most pups are born from late November to early December. There is no information on migration or diving.At sea, these fur seals can be quite animated at the surface, grooming and resting head down with hindflippers elevated and swaying in the air. They also raft at the surface with flippers tucked in a "jug-handle" position. The diet of this species is poorly known. Cumulative evidence from stomachs has yielded the remains of 5 varieties of squid. Local fishermen claim that these fur seals also consume various fishes and lobsters.

Conservation Status : Juan Fernandez fur seals have been severely exploited by humans. Records from sealers' logs, dating from the start of commercial sealing in 1687, account for approximately 4 million seals being taken from these islands. The species was thought to be extinct by 1900. In 1965 a relict population of approximately 200 fur seals were "rediscovered" on Mas Afuera Island. IUCN: Vulnerable.

The Juan Fernández fur seal (Arctocephalus philippii) is the second smallest of the fur seals, second only to the Galápagos fur seal. They are found only on the Pacific Coast of South America, more specifically on the Juan Fernández Islands and the Desventuradas Islands. There is still much that is unknown about this species. Scientists still do not know the average life span of this species, or the diet and behavior of males apart from the breeding season.