(Peters, 1866) - Juan Fernandez fur seal
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 shoulders sometimes appear silver-grey; 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, and subantarctic fur seals, 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.
The Juan Fernandez fur seal is restricted to the Juan Fernandez Archipelago in the eastern South Pacific Ocean off Chile and an incompletely known area of surrounding waters. When ashore, these fur seals prefer rocky and volcanic shorelines with boulders, grottos, overhangs, and caves.
Biology and Behaviour
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.
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.