The Juan Fernández Fur Seal (Arctocephalus philippii) is found on the Juan Fernández Islands and the Desventuradas Islands, located less than 900 km off the west coast of Chile, South America. Part of the Arctocephalus genus due to a their likeness to a bear in the head, it is unclear where ‘philippii’ originates from. The species has suffered from extensive exploitation in the past, but has since recovered numbers to some extent. Although the population is still relatively small at present, with a limited geographic range, their numbers are growing, and A. philippii do not qualify for anything other than a Least Concern listing with the IUCN at the current time. Estimated population size = 32,278.
A. philippii are a relatively small fur seal (males ♂ up to 2.1 m long/ 159 kg, females ♀ up to 1.5 m/ 50 kg). Both sets of flippers are rather short and fleshy, with little hair, and their bodies are short but stocky. Sexual dimorphism is obvious, with males larger and broader and sporting well-developed manes, as well as bulbous noses and long, pointed muzzles. Females, though robust, are much smaller and have more streamlined heads, with almost conical shaped faces. Vibrissae are proportionately short. Male individuals are usually dark brown to black, often with silver-tippedfur on the neck and mane, and sometimes a golden colour accenting their crown. Females are more often a dusky or grey colour with highlights on the chest and face.
These seals tend to feed mostly on a narrow range of migrating cephalopods and fish from the depths. As such they dive fairly shallowly, for short durations, and feed at or near the surface. Favoured prey include: lanternfish, sauries, jacks, anchovies, deep-sea smelt, squid and octopus. It is known they will forage during the day and night, and that they will travel long distances of up to 1000 km to make these dives. But this may reflect a shortage in food availability.
Sexual maturity – unknown. Though males ♂ mature later than females ♀.
A. philippii breed polygynously, with males forming both land and water territories at the medium to large rookeries, and females arriving to birth from November to January (peak December). Mating usually occurs on the shoreline a week or so after the mother has given birth, and gestation lasts for just under a year. When the pups are born they have a soft black fur which lightens over time to a brown and eventually sandy colour, before being moulted at 3-4 months. On average a week and a half after the birth, the mother returns to sea to forage, alternating week or two long trips away, with nursing periods of around a week. This continues for approximately 10 months, when the pup will be weaned. A post-natal adult moult then occurs. A. philippii are thought to live for around 13-23 years, though data is lacking for this species.