2010/02/07 01:47:45.899 US/Eastern

By Mark Nabong

Kingdom: Animalia

Phylum: Chordata

Subphylum: Vertebrata

Class: Mammalia

Order: Carnivora

Suborder: Caniformia

Family: Otariidae

Genus: Arctocephalus

Species: Arctocephalus townsendi

Geographic Range

The northernmost border of the range of A. townsendi is the Channel Islands, CA. The southern range border is Cedros Island, Baja California, Mexico. The only current breeding area is on Guadalupe Island, 290 km west of Baja California. The Guadalupe fur seal is the rarest of the fur seals, and it is also the only species of Arctocephalus found in the Northern Hemisphere. They have also been sighted as far south as Puerto Gurrero, near the Mexico/Guatemala border, as far north as the Point Reyes National Seashore in California, and possibly in the Gulf of California. It is possible that the true range of the species is underestimated due to the rarity of sightings. ( Aurioles-Gamboa and Hernandez-Camacho, April 1999 ; Seal Conservation Society, 2001 )

Biogeographic Regions:
nearctic ( native ); pacific ocean ( native ).

Habitat

Elevation

Depth
onshore to 17 m
( to 55.76 ft)

Guadalupe fur seals only live on rocky coasts and in the caves found along these shores. They can dive to an average maximum depth of 17m for an average of 2.5 minutes. ( Seal Conservation Society, 2001 ; Whitaker, 1997 )

These animals are found in the following types of habitat:
temperate ; tropical ; saltwater or marine .

Aquatic Biomes:
coastal .

Physical Description

Mass
50 to 160 kg
(110 to 352 lbs)

Length
1.90 m (high)
(6.23 ft)

The fur of Guadalupe fur seals is brownish gray dorsally, with a silvery and yellowish-gray "mane" on the nape of the neck. Their snouts are pointed, with a rust-orange color on the sides.

This species has great sexual dimorphism. Adult males usually weigh about 124 kg, and may get up to 160 kg, females weigh about 50 kg, rarely over 55. Males grow up to 1.9 m long, females to 1.4 m.

(Whitaker 1997; Wickens & York 1997)

Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .

Sexual dimorphism: male larger.

Reproduction

Breeding season
15 June - 22 July

Number of offspring
1 (average)

Gestation period
approximately 12 months (average)

Time to weaning
most likely 11 months (average)

Guadalupe fur seals have a polygynous breeding system, which involves a male seal with a territory (a bull) defending both his terriory and the females in his harem. The harem numbers between 4 to 12 females, each of which typically have one pup that they nurse.

Mating systems:
polygynous .

Male Guadalupe fur seals are territorial, like other fur seals. They defend harems that number an average of 6.2 breeding females for each territorial bull. Males will defend their territory for 35 to 122 days. Unlike most other seal species, the males of A. townsendi occasionally observe their harems from the water. Female Guadalupe fur seals mate 7-10 days after giving birth to a pup conceived the previous year (post-partum estrus). Females lactate for an average of 9-11 months; how this related to the actual length of time before weaning is unclear.

(Whitaker, 1997; Wickens & York, 1997)

Key reproductive features:
seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual .

Behavior

Mother seals use olfactory clues to find their pups after foraging trips.

The seals are not migratory, but a male and his females will occasionally diperse to new areas.

(Whitaker 1997; Wickens & York 1997)

Key behaviors:
motile ; territorial ; social .

Food Habits

Guadalupe fur seals eat a variety of fish, including lantern fish, mackerel, and fish in the muctophid family. Squid also constitute a major part of their diet. In all cases, the seals swim out to sea and dive for their prey items. During the breeding season, females make 2 to 6 day forging trips to sea, coming onshore in between each trip in order to suckle their pups.

Anchovy otoliths (bony concretions formed in the ears of fish) have been found the the digestive tracts of Guadalupe fur seals, but they are believed to be remains left from feeding of the seals by fishermen.

(Hanni et al. 1997; Seal Conservation Society 2001; Whitaker, 1997)

Primary Diet:
carnivore ( piscivore , molluscivore ).

Animal Foods:
fish; mollusks.

Ecosystem Roles

The Guadalupe fur seal plays the role of predator in the shoreline communities it inhabits.

(Whitaker 1997)

Economic Importance for Humans: Positive

Prehistorically, A. townsendi may have been hunted by Chumash Indians at San Miguel Island and other Channel Islands in California. The seal produces a rich, dense fur that was highly prized up until recent times, with the species nearly driven to extinction by seal hunters in the 1880's. In 1892, only seven individuals were known to exist. The population has rebounded, and the trade in the fur of Guadalupe fur seals is prohibited.

(Melin & DeLong 1999; Whitaker 1997)

Conservation Status

IUCN Red List: [link] :
Vulnerable.

US Federal List: [link] :
Threatened .

CITES: [link] :
Appendix I.

The Guadalupe fur seal was nearly hunted to extinction in the 1880's, with the known population numbering only 7 individuals in 1892. Other than two males sold to the San Diego Zoo in 1928, only one other GFS was sighted until 1954. Guadalupe Island was declared a seal sanctuary by the Mexican government in 1975. The Guadalupe fur seal was first placed on the "threatened" list in the US on March 11, 1967. By 1984 there were 1,600 seals in the Guadalupe Island population, including around 650 new pups. Current estimates place the population number at >7,000 individuals. Despite the bottlenecks of the late 1800's, there still remains a high level of genetic variability in the population. The population of Guadalupe fur seals is growing at the rate of 11.5% per annum.

(Bernardi et al. 1998; Seal Conservation Society, 2001; USFWS 2001; Whitaker 1997; Wickens & York 1997)

For More Information

Find Arctocephalus townsendi information at

Encyclopedia of Life

Contributors

Mark Nabong (author), University of Michigan.
Kate Teeter (editor), University of Michigan.

References

Aurioles-Gamboa, D., C. Hernandez-Camacho. April 1999. Notes on the southernmost records of the Guadalupe fur seal, *Arctocephalus townsendi*, in Mexico. Marine Mammal Science , 15(2): 581-583.

Bernardi, G., S. Fain, J. Gallo-Reynoso, A. Figueroa-Carranza, B. Le Beouf. 1998. Genetic variability in Guadalupe fur seals.. Journal of Heredity , 89(4): 301-305.

Hanni, K., D. Long, R. Jones, P. Pyle, L. Morgan. May 1997. Sightings and strandings of Guadalupe fur seals in Central and Northern California, 1988-1995.. Journal of Mammalogy , 78(2): 684-690.

Melin, S., R. DeLong. July 1999. Obervations of a Guadalupe fur seal (*Arctocephalus townsendi*) female and pup at San Miguel Island, California.. Marine Mammal Science , 15(3): 885-888.

Seal Conservation Society, 2001. "SCS: Guadalupe fur seal" (On-line). Accessed Tuesday, 20 November 2001 at http://www.pinnipeds.fsnet.co.uk/species/guadfur.htm .

US Fish & Wildlife Service, 11/20/2001. "Species List: Guadalupe fur seal profile" (On-line). Accessed Tuesday, 20 November 2001 at http://ecos.fws.gov/species_profile/species_profile.html?spcode=A0A8 .

Whitaker, J. 1997. National Audubon Society Field Guide to North American Mammals . New York: Alfred A. Knopf.

Wickens, P., A. York. April 1997. Comparative population dynamics of fur seals. Marine Mammal Science , 13(2): 241-292.

2010/02/07 01:47:47.181 US/Eastern

To cite this page: Nabong, M. 2002. "Arctocephalus townsendi" (On-line), Animal Diversity Web. Accessed February 09, 2010 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Arctocephalus_townsendi.html.

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students . ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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Arctocephalus townsendi
Guadalupe Fur Seal [ + ]

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Otariidae
Genus: Arctocephalus
species: townsendi
+ITIS +WoRMS

Description & Behavior

The Guadalupe fur seal, Arctocephalus townsendi (Merriam, 1897), whose Latin name means "bear headed" is an extremely dimorphic species, which means that males are significantly larger than females. Adult males measure 2.2 m in length on average and weigh 188 kg, while the average adult female reaches 1.5 m in length and 49 kg in weight. Females live almost twice as long as males, on average about 23 years compared to the male average life span of 13 years. The Guadalupe fur seal has a dark brown-black coat with light hairs on the back of the neck.

World Range & Habitat

The Guadalupe fur seal is the rarest of all fur seal species, and is the only species of Arctocephalus found north of the equator. Guadalupe fur seals are not migratory. Individuals are occasionally sighted as far south as Tapachula near the Mexico-Guatemala border and as far north as the Point Reyes National Seashore in California, and in the Gulf of California. The Guadalupe fur seal population is recovering from exploitation, and is estimated at approximately 7,000 individuals.

» GBIF occurrence data in Google Earth [ Tips ] | Ocean Biogeographic Information System (OBIS) (World Distribution) [about]

Feeding Behavior (Ecology)

The Guadalupe fur seal feeds on squid and fish. Research on a group of adult females showed them feeding south of Isla de Guadalupe, making round trips of 704- 4,092 km. They feed at night diving to an average depth of 17 m for an average of about 2.5 minutes. The primary predators of Guadalupe fur seals are sharks .

Life History

Very little data exists for the Guadalupe fur seal, partly because of its geographical isolation. The Guadalupe fur seal breeds on the Isla de Guadalupe and Isla Benito del Este off the coast of Baja California, Mexico on rocky beaches or in caves. Breeding season is from June to August. Adult males fight for territories containing an average of 4 females, although they have been known to breed with as many as 12 females in a single territory. Females give birth to a pup within a few days of their arrival, then mate 7-8 days later. After mating, she returns to feed at sea for 9-13 days after which she will return to nurse her pup for 5-6 days. This feeding cycle lasts 8-9 months, which is long compared to other fur seal species.

Conservation Status/Additional Comments

Guadalupe fur seals, Arctocephalus townsendi , were nearly extinct in the late 1700s and early 1800s due to commercial hunting. By 1825, they were nonexistent in California waters, but were hunted in Mexico until 1894. By 1928, the species was considered extinct but the species was rediscovered in 1954. Isla de Guadalupe is now a pinniped sanctuary, and the Guadalupe fur seal is fully protected by the government of Mexico. The species is also protected in the U.S. by California, as a Threatened species under the U.S. Endangered Species Act , and as a Depleted and Strategic species under the U.S. Marine Mammal Protection Act . The species is also listed as Near Threatened on the IUCN Red List and as an Appendix I species under CITES .

Individuals, particularly juvenile females, have been found stranded with injuries caused by entanglement in marine debris. Although little data exists, it is thought that Guadalupe fur seals may be killed by entanglement in drift and set gillnets. El Niño and Hurricane "Darby" caused a 33% pup mortality in 1992.