On the rocky shores of the Galapagos Islands, six to ten Galapagos fur seals may occupy an area of about 100 square metres (8). Grouping together in this manner may be largely due to the rarity of suitable rocky sites, but it also has the benefit of making females less vulnerable to predation or harassment (9). Breeding males establish larger territories, of around 200 square metres, which encompass a number of females (8).
The breeding season of the Galapagos fur seal lasts from mid-August to mid-November (5), when the cooler temperatures mean less heat stress and a greater availability of prey (8). A peak of births occurs in the last week of September or the first week of October (5), when females give birth to a single pup that has been carried for eight to twelve months (3). For the first five to ten days, the female will stay with the newborn, but after this period she alternates one to three days of feeding at sea with one to two days ashore with the pup. The pup is nursed for two to three years, sometimes even longer (8).
Just eight days after giving birth, the female Galapagos fur seal mates again (8). Being a polygynous mammal, one male may mate with between six and sixteen females within his territory (9). The rough terrain and large size of the male’s territory means that it can be difficult to successfully defend all the females within the area, and a rival male may sometimes invade and mate with a female (8). Defending a territory with threats and fighting can be tiring work, so the male Galapagos fur seal can often be seen cooling off in the sea at midday (8).
Although all female Galapagos fur seals mate shortly after giving birth, only a small percentage will give birth the following year if they are still feeding a pup. If a pup is born to a female that is still feeding a pup from the previous year, the newborn often starves, or is occasionally killed by the older sibling (8). Females mature at three to four years of age, while males become territorial breeding bulls between seven and ten years old (2).
While the Galapagos fur seal is capable of diving to much greater depths, it mainly undertakes short dives to between 10 and 50 metres (2) (3), where it feeds on a variety of fish and small squid (2) (5).