Animal Diversity Web

Ge­o­graphic Range

Arc­to­cephalus gazella, the Antarc­tic fur seal, has a very wide dis­tri­b­u­tion. They are mostly found in wa­ters south of the Antarc­tic Con­ver­gence, but some do in­habit areas slightly north of the Con­ver­gence. Most breed­ing pop­u­la­tions are found on South Geor­gia Is­land and Bird Is­land, while other pop­u­la­tions are found in the south Prince Ed­ward, Crozet, Ker­gue­len, and Mac­quarie Is­lands. Va­grants, how­ever, have been ob­served in the south­ern part of South Amer­ica and the Juan Fer­nan­dez Is­lands. Pop­u­la­tions in the south In­dian Ocean, south of the polar front, are found on Heard and Mc­Don­ald Is­lands and north of the polar front on dis­tances and have been seen from these breed­ing is­lands up to the ice edge of the polar front. Fe­males leave the breed­ing is­lands dur­ing the win­ter and be­tween breed­ing sea­sons trav­el­ling south to the mar­ginal ice zone and across the polar front. Bulls often re­main at the breed­ing is­lands dur­ing win­ter. Pups stay close to the beaches where they were born but usu­ally move on to the ocean as win­ter pro­gresses. (For­cada and Stani­land, 2009; Jef­fer­son, et al., 2008)

• Biogeographic Regions
• antarctica
  • native

Habi­tat

Antarc­tic fur seals spend much of their time in the ocean, hunt­ing for food. While on land, they pre­fer to stay in rocky habi­tats but will go to beaches and zones of veg­e­ta­tion. Males can dive up to a max­i­mum of 350 me­ters, while fe­males can only reach up to 210 me­ters. Fe­males can travel long dis­tances in the open ocean for long pe­ri­ods of time be­tween breed­ing. (For­cada and Stani­land, 2009; Jef­fer­son, et al., 2008)

• Habitat Regions
• polar
• terrestrial
• saltwater or marine

• Aquatic Biomes
• pelagic
• coastal

• Range depth

  350 (high) m

  1148.29 (high) ft

Phys­i­cal De­scrip­tion

Sex­ual di­mor­phism is very ev­i­dent in Antarc­tic fur seals. Males are four to five times heav­ier than fe­males and one and a half times longer. The av­er­age length of the males is 180 cm while the av­er­age length of fe­males is 129 cm. The av­er­age weight of males is 133 kg and for fe­males it is just 34 kg. Their body is cov­ered in hair ex­cept for the areas around the rhi­nar­ium (area around the nos­trils), ear tips, and the pal­mar sur­face of the flip­pers. They have two dif­fer­ent lay­ers of hair, the un­der-pelt, which is made up of fine fur for in­su­la­tion, and the other layer, which has two dif­fer­ent types of guard hairs. These seals have nails on their hind flip­pers that are well de­vel­oped and used for groom­ing. Antarc­tic fur seals also have the longest fa­cial vib­ris­sae, or whiskers, of any other pin­niped, reach­ing up to 45 cm in bulls. The bod­ies in both males and fe­males are thick, with long necks. Males are gray­ish brown in color, while their face is a darker gray. The chest may ap­pear to be a sil­very gray color as well. They have a heavy, griz­zled mane. Fe­male coats are also gray­ish brown in color, but their chest and neck are often white to gray. Pups are born black, with a gray­ish brown belly. They later molt to be com­pletely gray­ish brown. About one out of every 100 pups born is born with leucis­tic morph re­sult­ing in a creamy white or yel­low white ex­posed skin, which is nor­mally pig­mented. They have large ca­nines that are used in ter­ri­to­r­ial fights among males. A strong cor­re­la­tion has been found be­tween can­ina length, mass, and width in male Antarc­tic fur seals and body size. (Acevedo, et al., 2008; For­cada and Stani­land, 2009; Hoff­man, et al., 2010)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger
• ornamentation

• Range mass

  34 to 133 kg

  74.89 to 292.95 lb

• Range length

  129 to 180 cm

  50.79 to 70.87 in

Re­pro­duc­tion

Antarc­tic fur seals are polyg­y­nous and breed in colonies. Adult males ar­rive and es­tab­lish ter­ri­to­ries, about one month be­fore breed­ing fe­males come ashore, which is around mid Oc­to­ber or early No­vem­ber. Fe­males give birth to pups con­ceived from the pre­vi­ous sea­son. They mate again around six to seven days post-birth. Main­tain­ing ter­ri­to­ries is very costly for males. They lose about 1.5 kg in weight per day and ob­tain face in­juries from ter­ri­to­r­ial dis­putes. Con­se­quently, males do not tend to hold ter­ri­tory until they are at least eight years old. This also en­cour­ages a dom­i­nance hi­er­ar­chy on the breed­ing beaches. The most suc­cess­ful males de­fend the most de­sir­able ter­ri­to­ries (those near the water but above the high water mark). The weaker males oc­cupy ter­ri­to­ries higher up the beach. Each ter­ri­to­r­ial male is as­so­ci­ated with, on av­er­age, 15 fe­males or be­tween 1 to 27 fe­males. (Hoff­man and For­cada, 2011; Hoff­man, et al., 2003; Nowak and Walker, 2003)

• Mating System
• polygynous

Once re­turn­ing to shore fe­males give birth to one pup, on av­er­age, con­ceived from the pre­vi­ous year. The ges­ta­tion pe­riod is 11.75 months and im­plan­ta­tion is pos­si­bly de­layed. New­born pups weigh 6 kg on av­er­age. Males and fe­males re­turn to breed­ing sites, even within a few me­ters of pre­vi­ous ter­ri­to­ries. Sur­vival of their young from pre­vi­ous years prob­a­bly en­cour­ages re­turn­ing to the same spot year after year. Pups are born in Oc­to­ber or early No­vem­ber and weigh about six kilo­grams on av­er­age. While the mother is away, pups roam about and in­ter­act with each other. By early Jan­u­ary some pups are al­ready going to the water but can­not swim well until March. Fe­males use vo­cal­iza­tions to find the pup once she is back on land and con­firms the pup by scent. Pups are weaned at about 117 days and be­come re­pro­duc­tively ma­ture at three or four years old. (Hoff­man, et al., 2003; Nowak and Walker, 2003)

• Key Reproductive Features
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• delayed implantation

• Breeding interval

  Antarctic fur seals breed once a year.

• Breeding season

  Antarctic fur seals breed during the month of December.

• Range number of offspring

  0 to 2

• Average number of offspring

  1

  AnAge

• Average gestation period

  11.75 months

• Average gestation period

  257 days

  AnAge

• Average weaning age

  117 days

• Range age at sexual or reproductive maturity (female)

  3 to 4 years

• Range age at sexual or reproductive maturity (male)

  3 to 4 years

Fe­male Antarc­tic fur seals have to reg­u­larly for­age for food dur­ing the growth of their pups. Fe­males al­ter­nate for­ag­ing trips with short suck­ling bouts until the pups are weaned after about 117 days. They for­age at sea for 1 to 13 days at a time with an av­er­age trip du­ra­tion of 5 days. They then re­turn to feed the pup for about two days be­fore re­turn­ing to sea. (Hoff­man and For­cada, 2011; Hoff­man, et al., 2003; Nowak and Walker, 2003)

• Parental Investment
• female parental care
• pre-hatching/birth
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifes­pan/Longevity

In cap­tiv­ity the lifes­pan of Antarc­tic fur seals has not been well stud­ied and it re­mains un­known. In the wild, males live up to 15 years, while fe­males can live up to 25 years. (de Ma­g­a­l­haes and Costa, 2009)

• Range lifespan
  Status: wild

  25 (high) years

• Average lifespan
  Sex: female
  Status: wild

  23.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Sex: male
  Status: wild

  13.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Antarc­tic fur seals are con­sid­ered to be one of the most ter­res­trial pin­nipeds along with the leop­ard seal. They are able to move across slip­pery rocks and through the dense grasses faster than hu­mans. On a smooth sur­face, they are able to reach up to 20 km per hour. They can ex­ceed this speed while swim­ming. After the breed­ing sea­son is over and pups are weaned, the seals move to sea dur­ing win­ter months of May through No­vem­ber. It is not known where they go and if it is a di­rec­tional mi­gra­tion or sim­ply dis­per­sal. Some adult males and ju­ve­nile seals stay ashore all year round. When for­ag­ing, dives usu­ally av­er­age about 30 m in depth and last about two min­utes. (Hoff­man, et al., 2003; Nowak and Walker, 2003)

• Key Behaviors
• motile
• territorial
• dominance hierarchies

• Range territory size

  22 to 60 m^2

Home Range

Due to com­pe­ti­tion among males, ter­ri­tory size shrinks from 60 square me­ters in mid No­vem­ber to about 22 square me­ters in De­cem­ber. A dom­i­nance hi­er­ar­chy main­tains ter­ri­to­ries. (Hoff­man, et al., 2003; Nowak and Walker, 2003)

Com­mu­ni­ca­tion and Per­cep­tion

Antarc­tic fur seals use vo­cal­iza­tions to com­mu­ni­cate. Males use two main calls. One is a threat­en­ing roar which is di­rected to­wards other males. Else, it is used as a re­sponse to a spe­cific threat, such as a preda­tor. The other call they make is a "huff-chuff". This call is used when mov­ing around breed­ing ter­ri­to­ries, in­ter­act­ing with fe­males, and is used as a sign of sta­tus. Fe­males can roar and "huff-chuff", but their main form of com­mu­ni­ca­tion is with their pups. They use both sound and smell to es­tab­lish a bond. The sound is a high pitched call that is re­in­forced after the pup is born so when the mother re­turns from hunt­ing trips she can make the sound and the pup will rec­og­nize it. The mother and pup use smell at close dis­tances to con­firm each other's iden­tity. (For­cada and Stani­land, 2009)

• Communication Channels
• acoustic
• chemical

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Antarc­tic fur seals mainly feed on fish, krill, crus­tacean, and cephalopods, such as squid and oc­topods. Fish con­si­tute al­most 75% of the diet in non-win­ter months. At the South Geor­gia Is­lands, the main fish prey is the mack­erel ice­fish. How­ever, they also con­sume krill in large quan­ti­ties as well. Lac­tat­ing fe­males mainly feed on krill. If krill is un­avail­able, they turn to fish. Dur­ing win­ter months, adult and sub-adult males feed on 50% krill and 50% fish. They also prey on some smaller pen­guins (4-8 kg) as well, such as rock­hop­per and mac­a­roni pen­guins. Pre­vi­ous stud­ies sug­gested that fur seals only at­tacked king pen­guins on land, but Char­bon­nier et al. (2007) ob­served that adult males at­tack king pen­guins at sea, too. Al­though adult male and fe­male Antarc­tic fur seals chased king pen­guins at sea, only adult males were suc­cess­ful in catch­ing and killing or in­jur­ing the pen­guins. (Casaux, et al., 1998; Char­bon­nier, et al., 2007)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • piscivore
  • eats non-insect arthropods

• Animal Foods
• birds
• fish
• aquatic crustaceans

Pre­da­tion

One major preda­tor of Antarc­tic fur seeals are the leop­ard seals. They are a major con­trib­u­tor to high seal pup mor­tal­ity rates es­pe­cially be­tween Jan­u­ary and March be­fore the pups are weaned. This has lim­ited the growth of the colony at Ele­phant and Liv­ingston Is­lands in the South Shet­lands. Antarc­tic fur seals also are also preyed upon by killer whales and sharks. (Boveng, et al., 1998)

• Known Predators

  • Leopard seal (Hydrurga leptonyx)
  • killer whales (Orcinus orca)
  • sharks

Ecosys­tem Roles

Mem­bers of Antarc­tic fur seals are key preda­tors of krill and var­i­ous species of fish and squid. It has been found that there is a cor­re­la­tion be­tween size of breed­ing colonies and prey avail­abil­ity, based upon short term en­vi­ron­men­tal changes and the ef­fect it has on the re­pro­duc­tive suc­cess of fe­males.

Lung­worms in­fect three mem­bers of the fur seals group. These par­a­sites in­fect the lungs of their host. ("Pro­posal to De-list Antarc­tic Fur Seals as Spe­cially Pro­tected Species", 2006; Dai­ley,, 2009)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

In the 1800 and 1900s Antarc­tic fur seals were widely hunted for their fur. Since this time, how­ever, Antarc­tic fur seals have had lit­tle eco­nomic im­por­tance to hu­mans. Al­though, in­creas­ing com­mer­cial krill har­vest­ing could af­fect pop­u­la­tions in the fu­ture. ("Pro­posal to De-list Antarc­tic Fur Seals as Spe­cially Pro­tected Species", 2006; "Pro­posal to De-list Antarc­tic Fur Seals as Spe­cially Pro­tected Species", 2006)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of Antarc­tic fur seals on hu­mans.

Con­ser­va­tion Sta­tus

The num­ber of Antarc­tic fur seals were re­duced to below 3,000 in­di­vid­u­als in the 1800s. In 1964, they be­came a “spe­cially pro­tected species,” which is a term given only to the “most vul­ner­a­ble and en­dan­gered species,” (Pro­posal to De-list, 2006). Since then, Antarc­tic fur seals have greatly ex­tended their range and are at lit­tle risk of ex­tinc­tion. Total pop­u­la­tion num­bers are es­ti­mated at four to seven mil­lion seals and are in­creas­ing. In the CITES ap­pen­dices Antarc­tic fur seals are listed in Ap­pen­dix II, in­di­cat­ing that while they are not cur­rently threat­ened with ex­tinc­tion they may be­come so un­less trade is closely con­trolled. ("Pro­posal to De-list Antarc­tic Fur Seals as Spe­cially Pro­tected Species", 2006)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  Appendix II

• State of Michigan List

  No special status

Con­trib­u­tors

Car­son Widener (au­thor), Rad­ford Uni­ver­sity, Karen Pow­ers (ed­i­tor), Rad­ford Uni­ver­sity, Kier­sten Newtoff (ed­i­tor), Rad­ford Uni­ver­sity, Melissa Whistle­man (ed­i­tor), Rad­ford Uni­ver­sity, Laura Podzikowski (ed­i­tor), Spe­cial Pro­jects.

Ref­er­ences

Antarc­tic Treaty Con­sul­ta­tive Meet­ing. Pro­posal to De-list Antarc­tic Fur Seals as Spe­cially Pro­tected Species. WP039. Ed­in­burgh: Sec­re­tariat of the Antarc­tic Treaty. 2006. Ac­cessed April 24, 2012 at http://​www.​scar.​org/​treaty/​atcmxxix/​atcm29_​wp039.​pdf.

Acevedo, J., D. Tor­res, A. Aguayo-Lobo. 2008. Rare piebald and par­tially leucis­tic Antarc­tic fur seals, Arc­to­cephalus gazella, at Cape Shirreff, Liv­ingston Is­land, Antarc­tica. Polar Bi­ol­ogy, 32/1: 41-45.

Boveng, P., L. Hiruki, M. Schwartz, J. Bengston. 1998. Pop­u­la­tion growth of the Antarc­tic fur seals: Lim­i­ta­tion by a top preda­tor, the leop­ard seal?. Ecol­ogy So­ci­ety of Amer­ica, 79/8: 2863-2877.

Boyd, I., A. Mur­ray. 2001. Mon­i­tor­ing a ma­rine ecosys­tem using re­sponses of upper trophic level preda­tors. Jour­nal of An­i­mal Ecol­ogy, 70/5: 747-760.

Casaux, R., A. Ba­roni, A. Car­lini. 1998. The diet of the Antarc­tic fur seal Arc­to­cephalus gazella at Har­mony Point, Nel­son Is­land, South Shet­land Is­lands. Polar Bi­ol­ogy, 20/6: 424-428.

Char­bon­nier, Y., K. De­lord, J. Thei­bot. 2007. King-size fast food for Antarc­tic fur seals. Polar Bi­ol­ogy, 33/5: 721-724.

Dai­ley,, M. 2009. A new species of Parafi­laroides (Ne­ma­toda: Fi­laroi­di­dae) in three species of fur seals (Car­nivora: Otari­idae) from the South­ern Hemi­sphere. Amer­i­can So­ci­ety of Par­a­sitol­o­gists, 95/1: 156-159.

For­cada, J., I. Stani­land. 2009. Antarc­tic Fur Seal Arc­to­cephalus gazella. Pp. 36-42 in W Per­rin, B Wur­sig, J Thewis­sen, eds. En­cy­clo­pe­dia of Ma­rine Mam­mals, Vol. 2, 2nd Edi­tion. New York: El­se­vier.

Gaste­bois, C., M. Vi­viant, C. Guinet. 2011. On­togeny of aquatic be­hav­iours in Antarc­tic fur seal (Arc­to­cephalus gazella) pups in re­la­tion to growth per­for­mances at Ker­gue­len Is­lands. Polar Bi­ol­ogy, 34/7: 1097-1103.

Hoff­man, J., I. Boyd, W. Amos. 2003. Male re­pro­duc­tive strat­egy and the im­por­tance of ma­ter­nal sta­tus in the Antarc­tic fur seal Arc­to­cephalus gazella. Evo­lu­tion, 57/8: 1917-1930.

Hoff­man, J., J. For­cada. 2011. Ex­treme natal philopa­try in fe­male Antarc­tic fur seals (Arc­to­cephalus gazella). Mam­malian Bi­ol­ogy, 77/1: 71-73.

Hoff­man, J., N. Han­son, J. For­cada, P. Trathan, W. Amos. 2010. Get­ting long in the tooth: A strong pos­i­tive cor­re­la­tion be­tween ca­nine size and het­erozy­gos­ity in Antarc­tic fur seals Arc­to­cephalus gazella. Jour­nal of Hered­ity, 101/5: 527-538.

Jabour, J. 2008. Suc­cess­ful con­ser­va­tion- then what? The de-list­ing of Arc­to­cephalus fur seal species in Antarc­tica. Jour­nal of In­ter­na­tional Wildlife and Pol­icy, 11/1: 1-29.

Jef­fer­son, T., M. Web­ber, R. Pit­man. 2008. Ma­rine Mam­mals of the World. New York: El­se­vier.

Lea, M., M. Hin­dell, C. Guinet, S. Goldswor­thy. 2001. Vari­abil­ity in the div­ing ac­tiv­ity of Antarc­tic fur seals, Arct­cephalus gazella, at Iles Ker­gue­len. Polar Bi­ol­ogy, 25/4: 269-279.

Luque, S., J. Arnould, E. Miller, Y. Cherel, C. Guinet. 2007. For­ag­ing be­hav­iour of sym­patric Antarc­tic and sub­antarc­tic fur seals: Does their con­trast­ing du­ra­tion of lac­ta­tion make a dif­fer­ence?. Ma­rine Bi­ol­ogy, 152/1: 213-224.

Makhado, A., M. Bester, S. Kirk­man, P. Pis­to­rius, J. Fer­gu­son, N. Klages. 2007. Prey of the Antarc­tic fur seal Arc­to­cephalus gazella at Mar­ion Is­land. Polar Bi­ol­ogy, 31/5: 575-581.

Nowak, R., E. Walker. 2003. Arc­to­cephalus gazella. Pp. 77-78 in Walker's Ma­rine Mam­mals of the World, Vol. 6, Sixth Edi­tion. Bal­ti­more: The Johns Hop­kins Uni­ver­sity Press.

Osman, L., R. Hucke- Gaete, C. Moreno, D. Tor­res. 2003. Feed­ing ecol­ogy of Antarc­tic fur seals at Cape Shirreff, South Shet­lands, Antarc­tica. Polar Bi­ol­ogy, 27/2: 92-98.

Reid, K., J. Crox­all. 2001. En­vi­ron­men­tal re­sponse of up­per-trophic level preda­tors re­veals a sys­tem change in an Antarc­tic ma­rine ecosys­tem. Pro­ceed­ings: Bi­o­log­i­cal Sci­ences, 268/1465: 377-384.

Stani­land, I., I. Boyd, K. Reid. 2007. An en­ergy–dis­tance trade-off in a cen­tral-place for­ager, the Antarc­tic fur seal (Arc­to­cephalus gazella). Ma­rine Bi­ol­ogy, 152/2: 233-241.

Tor­res, D., J. Acevedo, D. Tor­res, R. Var­gas, A. Aguayo-Lobo. 2011. Va­grant Sub­antarc­tic fur seal at Cape Shirreff, Liv­ingston Is­land, Antarc­tica. Polar Bi­ol­ogy, 35/3: 469-473.

de Ma­g­a­l­haes, J., J. Costa. 2009. A data­base of ver­te­brate longevity records and their re­la­tion to other life his­tory traits. Jour­nal of Evo­lu­tion­ary Bi­ol­ogy, 22/8: 1770-1774.