Guadalupe fur seal (Arctocephalus townsendi)
|Also known as:||Lower Californian fur seal|
|Synonyms:||Arctophoca philippii townsendi|
|French:||Arctocéphale De Guadalupe, Otarie À Fourrure D'Amérique|
|Spanish:||Oso Marino De Guadalupe|
|Size||Male length: 1.8 – 1.9 m (2)|
Female length: 1.2 – 1.4 m (2)
Male weight: 160 – 170 kg (2)
Female weight: 45 – 55 kg (2)
Classified as Near Threatened (NT) on the IUCN Red List (1), and listed on Appendix I of CITES (3).
The Guadalupe fur seal was once considered extinct, after being decimated by poaching for its dense, luxurious underfur (2). Remarkably, the species was rediscovered in 1954 with just 14 individuals remaining and, despite a tremendous recovery, it still remains the rarest of all fur seal species (2) (4). In males, the thick, dense coat is dark, greyish-brown to greyish-black. Much of the head and back of the neck may appear yellowish, and a silvery to yellowish-grey mane of long, coarse hair exists on the nape of the thick, muscular neck (2) (5). Females are similarly coloured dark, greyish-brown to greyish-black, but often appear paler, creamy-grey on the underside of the neck and chest. Guadalupe fur seals have elongated, pointy snouts with whitish-cream whiskers, and the male has a large and bulbous nose (2).
The Guadalupe fur seal used to have a much wider distribution, but for most of the 20th century breeding was restricted to only one island; Isla de Guadalupe, off the coast of Baja California, Mexico (4). In 1997 a group of Guadalupe fur seals was observed in Islas San Benito, 165 miles south west of Isla Guadalupe (6). In 2006 and 2007 the first pups were seen in San Benito, and the species has spread out all around the San Benito Archipelago. Non-breeding seals range as far north as the Farallon Islands and Sonoma County, California, and south into the Gulf of California (5).
When ashore, Guadalupe fur seals live and breed in rocky habitats, such as volcanic caves and grottos (2).
Like other fur seals, Guadalupe fur seals are territorial, with adult males fighting to form territories, and then endeavouring to accumulate females into their territories (5). Females start arriving at the breeding sites from mid-June to July or August, and give birth to a pup conceived the previous season within days of their arrival (5). About seven to ten days after giving birth the mother mates and then leaves to feed at sea (5). For the next eight to eleven months before the pup is weaned (5), the female will spend alternate periods of nine to thirteen days feeding at sea and nursing periods of five to six days back on land (7). Their search for prey may take them up to 500 kilometres away from their breeding sites and most of their dives are down to a depth of 50 metres (8). The Guadalupe fur seal diet is quite specialized on squid (95 percent) but also includes a few fishes (5) (9).
Prized for their luxurious underfur, Guadalupe seals were hunted to near extinction in the 19th century (2) (10). Following its rediscovery in 1954, when just 14 individuals were found, the species has experienced a remarkable recovery, with population numbers having rebounded to a far healthier 7,348 by the early 1990s (10). Nevertheless, some Guadalupe seals may still be killed through entanglement in drift and set gillnets and individuals, particularly juvenile females, have been found stranded with injuries caused by entanglement in marine debris. In addition, El Niño and Hurricane Darby were responsible for 33 percent pup mortality in 1992, but it is not known how the population was affected by the 1997 to 1998 El Niño event (7).
In 1975, the Isla de Guadalupe was declared a sanctuary by the Mexican government and the Guadalupe fur seal is now fully protected under Mexican law (2). The species is also protected in the U.S. portion of its range by Californian law and is listed on Appendix I of CITES, prohibiting any international trade (3). Thankfully, these measures have produced a dramatic rise in numbers, and the future looks a little brighter for the world’s rarest fur seal (10).
For more information on the Guadalupe fur seal, other seal species and their conservation see:
Seal Conservation Society:
International Marine Mammal Association Inc.:
Authenticated (20/11/07) by Dr David Aurioles Gamboa, Laboratorio de Ecologia de Pinnipedos "Burney J. Le Boeuf", Centro Interdisciplinario de Ciencias Marinas,
Instituto Politecnico Nacional, Mexico.
IUCN Red List (November, 2008)
- Jefferson, T.A., Leatherwood, S. and Webber, M.A. (1993) FAO Species Identification Guide. Marine Mammals of the World. Food and Agriculture Organization of the United Nations, Rome.
CITES (November, 2006)
- Arnould, J.P.Y. (2002) Southern Fur Seals. In: Perrin, W.F., Würsig, B. and Thewissen, J.G.M. (Eds) Encyclopedia of Marine Mammals. Academic Press, London.
- Macdonald, D. (2001) The New Encylopedia of Mammals. Oxford University Press, Oxford.
- Maravilla, O. and Lowry, M. (1999) Incipient breeding colony of Guadalupe fur seal at Isla Benito del Este, Baja California, México. Marine Mammal Science, 15(1): 239 - 241.
Seal Conservation Society (November, 2006)
- Gallo, J.P. (1994) Factors affecting the population status of the Guadalupe fur seal, Arctocephalus townsendi (Merriam, 1897), at Isla Guadalupe, Baja California, México. PhD Thesis, University of California, Santa Cruz, U.S.A.
- Aurioles-Gamboa, D. and Camacho-Ríos, F.J. (2007) Diet and feeding overlap of two otariids, Zalophus californianus and Arctocephalus townsendi: Implications to survive environmental uncertainty. Aquatic Mammals, 33(3): 315 - 326.
Smithsonian National Museum of Natural History (November, 2006)