Galapagos fur seal  (Arctocephalus galapagoensis)

The scientific name of this marine mammal, Arctocephalus, comes from Greek words that mean ‘bear headed' (3), and with its short, pointed muzzle, little button-like nose and fairly large eyes (5), the Galapagos fur seal does indeed bear a resemblance to its land-dwelling, carnivorous ancestors (3). The coat of this fur seal varies from dark brown to dark grey, with light-tipped, longer guard hairs giving a grizzled appearance (3) (6). Male Galapagos fur seals also have a mane of slightly longer hairs, from the top of their head to their shoulders (5). Both the muzzle and the fur on the undersides is paler (3), with females and subadults having a pale greyish-tan chest and rusty-tan belly (5), and the skin on the flippers is blackish (6). Galapagos fur seal pups have a blackish-brown coat, sometimes with greyish or whitish margins around the mouth and nose (5).

Endemic to the Galapagos Islands (3), where it is widely distributed. The main colonies occur on the western islands of the archipelago, with Isla Fernandina and Isla Isabela holding the largest populations (2).

When ashore, the Galapagos fur seal prefers rocky areas where it can seek shelter from the sun under ledges and between large boulders (5).

On the rocky shores of the Galapagos Islands, six to ten Galapagos fur seals may occupy an area of about 100 square metres (7). Grouping together in this manner may be largely due to the rarity of suitable rocky sites, but it also has the benefit of females being less vulnerable to predation or harassment when in large groups (8). Breeding males establish larger territories, around 200 square metres, which encompass a number of females (7).

The breeding season lasts from mid-August to mid-November (5), when the cooler temperatures mean less heat stress and a greater availability of prey (7). 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 mother will stay with her 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 (7).

Just eight days after giving birth, the female mates (7). Being a polygynous mammal, one male may mate with between six and sixteen females within his territory (8). 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 (7). Defending a territory with threats and fighting can be tiring work, so the male can often be seen cooling off in the sea at midday (7).

Although all females 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 (7). 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).

During the nineteenth century, the Galapagos fur seal was severely impacted by the large-scale commercial seal hunting that was rampant at the time (3) (7). By the early twentieth century, the Galapagos fur seal was believed to be extinct, until a small colony was discovered in 1932-33 (7). Since then, and following the end of extensive seal hunting (3), numbers have increased substantially (7), and the Galapagos fur seal is no longer exploited (2). Today, the spread of feral dogs on the Galapagos Islands may jeopardise the future of some of the fur seal colonies (2).

The Galapagos fur seal is fully protected by the Galapagos National Park Service under Ecuadorean law (2). It will also benefit from the management of the Galapagos Islands and the surrounding waters as a national park and marine reserve (5) (9). As one of the first sites to be designated a Natural World Heritage Site (9), the recognition of the Galapagos' incredible and unique ecosystem will hopefully ensure the preservation of the islands' fauna and flora for generations to come.

For further information see:

• Seal Conservation Society:
  www.pinnipeds.org
• Charles Darwin Foundation:
  www.darwinfoundation.org/en

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk