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).