Brown fur seal

The brown fur seal (Arctocephalus pusillus), also known as the Cape fur seal, South African fur seal, and Australian fur seal, is a species of fur seal.

Brown fur seal
Arctocephalus pusillus - SE Tasmania
Hauling-out on the Hippolyte Rocks off the east coast of Tasmania
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Clade: Pinnipedia
Family: Otariidae
Genus: Arctocephalus
Species:
A. pusillus
Binomial name
Arctocephalus pusillus
(Schreber, 1775)
Subspecies
  • A. p. pusillus
  • A. p. doriferus
Arctocephalus pusillus distribution
Distribution of the brown fur seal, dark blue: breeding colonies; light blue: nonbreeding individuals

Description

Arctocephalus pusillus 1
A fur seal grooming itself at the Cape Cross Seal Reserve on the Skeleton Coast
Arctocephalus pusillus01
Skull of male brown fur seal

The brown fur seal is the largest and most robust fur seal. It has a large and broad head with a pointed snout that may be flat or turned up slightly.[2] They have external ear flaps (pinnae) and their whiskers (vibrissae) are long, and may extend backward past the pinnae, especially in adult males. The fore flippers are covered with sparse hair over about three-quarters of their length. The hind flippers are short relative to the large body, with short, fleshy tips on the digits.[2] The size and weight of the brown fur seal depends on the subspecies. The Southern African subspecies is on average slightly larger than the Australian subspecies. Males of the African subspecies (A. p. pusillus) are 2.3 m (7.5 ft) in length on average and weigh 200–300 kg (440–660 lb).[3] Females are smaller, averaging 1.8 m (5.9 ft) in length and typically weighing 120 kg (260 lb).[4] Males of the Australian subspecies (A. p. doriferus) are 2.0–2.2 m (6.6–7.2 ft) in length and weigh 190–280 kg (420–620 lb).[5] Females are 1.2–1.8 m (3.9–5.9 ft) length and weigh 36–110 kilograms (79–243 lb).[4]

Adult male brown fur seals are dark gray to brown, with a darker mane of short, coarse hairs and a light belly, while adult females are light brown to gray, with a light throat and darker back and belly. The fore flippers of the fur seal are dark brown to black.[2] Pups are born black and molt to gray with a pale throat within 3-5 months.[2] The skull of the African subspecies has a larger crest between the mastoid process and the jugular process of the exoccipital.[4]

Ecology

Arctocephalus pusillus 4 - Cape fur seal
Baby seal
Fur Seals on Duiker Island
A fur seal colony at Duiker Island, South Africa
Seal at the Cape Town Scuba Diving
Fur seal underwater at Agulhas Bank
Arctocephalus pusillus 5 - Cape fur seal
Cape Cross colony, Namibia

The African fur seal lives around the southern and southwestern coast of Africa from Cape Cross in Namibia and around the Cape of Good Hope to Black Rocks near Port Elizabeth in the Eastern Cape province.[2] The Australian fur seal lives in Bass Strait, at four islands off Victoria in southeastern Australia, and five islands off Tasmania.[2] Brown fur seals prefer to haul out and breed on rocky islands, rock ledges and reefs, and pebble and boulder beaches. However, some large colonies can be found on sandy beaches.[2] Fur seals spend most of the year at sea, but are never too far from land. They have been recorded 160 km from land, but this is not common.[4]

The African fur seal's diet is made of up to 70% fish, 20% squid, and 2% crab.[6] Also eaten are other crustaceans, cephalopods and sometimes birds.[4][6] In rare instances, they have even been documented attacking and eating sharks. A recent incident occurred off Cape Point, South Africa, where a large male was observed attacking and killing five blue sharks between 1.0 and 1.4 m long. Observers concluded that the seal likely killed the sharks to eat the fish-rich contents of their stomachs, as well as their livers as a source of energy.[7] The Australian fur seal mostly eats squid, octopus, fish, and lobsters.[4][6] The brown fur seal dives for its food. The African subspecies can dive as deep as 204 m and for as long as 7.5 minutes.[8] The Australian subspecies generally feeds at lower depths, diving on average 120 m[6] and can reach as deep as 200 m.[8]

The brown fur seal's main predator is the great white shark, although they are also preyed upon by various other animals, such as killer whales and vagrant southern elephant seals.[9] Land-based predators include black-backed jackals and brown hyenas on the Skeleton Coast in Namibia. In False Bay, the seals employ a number of antipredatory strategies while in shark-infested waters, such as:

  • Swimming in large groups and harassing sharks in the vicinity
  • Low porpoising to increase subsurface vigilance
  • Darting in different directions to cause confusion when attacked
  • Using their greater agility to stay out of reach
  • Riding near the dorsal fin to keep out of reach of the shark's jaws when attacked[10]

Behaviour

Arctocephalus pusillus Colony Friar Island
Brown fur seal colony at Friar Islands, Tasmania
Arctocephalus pusillus (Cape fur seals)
Brown fur seals in Cape Cross
Arctocephalus pusillus 3 - Cape fur seal
Suckling

Acoustic behavior

Australian fur seals are social animals that use vocalizations in a broad range of contexts. These vocalizations have been shown to contain individually unique properties important for enabling individual recognition.[11] This is particularly important for the reunion of mothers and pups that experience repeated separations whilst mothers are out at sea foraging, sometimes for days at a time. Upon their return, mothers need to locate their pups.[12][13] This reunion process may also be facilitated through a combination of smell and spatial cues.

In males, increases in testosterone and calling rates are seen in conjunction with the onset of the breeding season.[14] Males can also differentiate neighboring males from stranger males, responding more aggressively to the vocalizations of strangers.[15] This difference in response is suspected because the threat posed by a stranger is unknown and potentially greater than their neighbor, which they would have previously encountered while establishing their territories.[16][17]

Breeding behaviour

Brown fur seals often gather into colonies on rookeries in numbers ranging from 500–1500, at least for the Australian subspecies.[4] While fur seals spend most of the year at sea, they never fully evacuate the rookeries, as mothers and pups return to them throughout the year. No dispersal from a colony is established, although some fur seals from one colony have been found at another. True boundaries do not exist between the colonies. When at sea, they travel in small feeding groups. Brown fur seals begin to breed in the middle of October, when males haul out on shore to establish territories though display, vocalisations, sparring, and sometimes actual combat [1]. They fast at this time and do not eat until after mating in November or December. When the females arrive, they fight among themselves for territories in which to give birth. Female territories are smaller than those of males and are always located within them. Females within a male's territory can be considered part of his harem. However, males do not herd the females, which are free to choose their mates and judge them based on the value of their territories. For the Australian fur seals, 82% of copulations are performed by males whose territories are located directly at the water's edge.[8] Copulation between the male and his females begins 6 days after they give birth to their pups conceived from the previous year. However, a delay occurs in the implantation of the blastocyst, which lasts 4 months in the African subspecies and 3 months in the Australian subspecies.[8] Gestation for the brown fur seal typically lasts a year less a few days.[8]

After mating, females begin alternating brief periods of foraging at sea with several days ashore nursing their pups.[2] Foraging trips last about 7 days in winter and about 4 days in summer and autumn. When a mother returns from sea to feed her pup, she emits a loud call which attracts all the nearby pups, but she only responds to her pup. She possibly can recognize her pup by smell.[8] When left alone, pups gather in groups and play during the evening.[4] Pups are usually weaned at 4–6 months old.[2]

Human interactions

Fur seal, Walvis Bay (Namibia)
Fur seals used for tourist attraction in Namibia
Seal Gaston
Brown fur seal Gaston in Prague Zoo

This species is an inquisitive and friendly animal when in the water, and often accompanies scuba divers. They swim around divers for periods of several minutes at a time, even at a depth of 60 m. On land, they are far less relaxed and tend to panic when people come near them.

Australian fur seals were hunted intensively between 1798 and 1825 for commercial reasons. Seal hunting stopped in Australia in 1923, and their population is still recovering, causing increasing friction with South Australian fishermen as their range expands.[18] Breeding and haul-out sites are protected by law. South African fur seals have a very robust and healthy population. Harvesting of seals was outlawed in South Africa in 1990.

Brown fur seals are still harvested in Namibia. Permits are issued for the killing of pups for their luxurious fur and adult males for their genitalia, which are considered an aphrodisiac in some countries. It is also considered necessary to limit seal numbers in Namibia because of the supposed effect seals have on the country's fish harvest. Research by environmental groups disputes this.[19]

References

  1. ^ Hofmeyr, G. & Gales, N. (2008). "Arctocephalus pusillus". IUCN Red List of Threatened Species. Version 2008. International Union for Conservation of Nature. Retrieved 30 January 2009.
  2. ^ a b c d e f g h i Randall R. Reeves; Brent S. Stewart; Phillip J. Clapham; James A. Powell (2002). National Audubon Society Guide to Marine Mammals of the World. Alfred A. Knopf, Inc. ISBN 0375411410.
  3. ^ "The S.A. Fur Seal". Botany.uwc.ac.za. 1 February 2001. Archived from the original on 1 July 2014. Retrieved 13 April 2013.
  4. ^ a b c d e f g h King, J. 1983. Seals of the World. Ithaca, New York: Comstock Publishing Associates.
  5. ^ Arnould, John P.Y.; Hindell, Mark A. (2001). "Dive behaviour, foraging location... preview & related info". Canadian Journal of Zoology. 79: 35–48. doi:10.1139/cjz-79-1-35. Retrieved 2013-04-13.
  6. ^ a b c d Schliemann, H. 1990. Eared Seals and Walruses. Pp. 168–203 in B. Grzimek, ed. Grzimek's Encyclopedia of Mammals. New York: McGraw-Hill.
  7. ^ "Seal attack! Hungry creature eats five blue sharks in rare images of sea mammal turning the tables on predator of the deep". Mail Online. January 29, 2013. Retrieved February 1, 2013.
  8. ^ a b c d e f Riedman, M. 1990. The Pinnipeds: Seals, Sea Lions, and Walruses. Berkeley: University of California Press.
  9. ^ Penry, Gwenith S.; Baartman, Ashwynn C.; Bester, Marthán N. (2013). "Vagrant elephant seal predation on Cape fur seal pups, Plettenberg Bay, South Africa". Polar Biology. 36 (9): 1381–1383. doi:10.1007/s00300-013-1350-4.
  10. ^ Anti-Predatory Strategies of Cape Fur Seals at Seal Island
  11. ^ Tripovich, J.S.; Canfield, R.; Rogers, T.L.; Arnould, J.P.Y. (2008). "Characterisation of Australian fur seal vocalizations during the breeding season". Marine Mammal Science. 24 (4): 913–928. doi:10.1111/j.1748-7692.2008.00229.x.
  12. ^ Tripovich, J.S.; Rogers, T.L.; Canfield, R.; Arnould, J.P.Y (2006). "Individual variation in the pup attraction call produced by female Australian fur seals during early lactation". Journal of the Acoustical Society of America. 120 (1): 502–509. doi:10.1121/1.2202864.
  13. ^ Tripovich, J.S.; Canfield, R.; Rogers, T.L.; Arnould, J.P.Y. (2009). "Individual variation of the Female Attraction Call produced by Australian fur seal pups throughout the maternal dependence period". Bioacoustics. 18 (3): 259–276. doi:10.1080/09524622.2009.9753605.
  14. ^ Tripovich, J.S.; Rogers, T.L.; Dutton, G. (2009). "Faecal testosterone concentrations and the acoustic behavior of two male captive Australian fur seals". Australian Mammalogy. 31 (2): 117–122. doi:10.1071/AM09009.
  15. ^ Tripovich, J.S.; Rogers, T.L.; Arnould, J.P.Y. (2005). "Species-specific characteristics and individual variation of the Bark Call produced by male Australian fur seals (Arctocephalus pusillus doriferus)". Bioacoustics. 15 (1): 502–509. doi:10.1080/09524622.2005.9753539.
  16. ^ Tripovich, J.S.; Charrier, I.; Rogers, T.L.; Canfield, R.; Arnould, J.P.Y. (2008). "Acoustic features involved in the neighbour-stranger vocal recognition process in male Australian fur seals". Behavioural Processes. 79 (1): 74–80. doi:10.1016/j.beproc.2008.04.007. PMID 18571339.
  17. ^ Tripovich, J.S.; Charrier, I.; Rogers, T.L.; Canfield, R.; Arnould, J.P.Y. (2008). "Who goes there? The dear-enemy effect in male Australian fur seals (Arctocephalus pusillus doriferus)". Marine Mammal Science. 24 (4): 941–948. doi:10.1111/j.1748-7692.2008.00222.x.
  18. ^ "Aggressive fur seals attacking rare birds, pelicans and fishing nets, SA fishermen warn". 891 ABC Adelaide. 2015-04-24. Retrieved 2015-04-24.
  19. ^ South African and Australian Fur Seals. Seal Conservation Society. Accessed 7 February 2013.

External links

Arctocephalus

The genus Arctocephalus consists of fur seals. Arctocephalus translates to "bear head."

Arctophoca

The genus Arctophoca is a proposed genus of pinnipeds, containing most species of fur seal. Usually, all fur seals are included in the genus Arctocephalus, but recent studies has shown the genus to be paraphyletic. In that case, only the brown fur seal remains in Arctocephalus, while the genus Arctophoca is resurrected for the remaining species. This split is however not yet official.

Asiatic linsang

The Asiatic linsang (Prionodon) is a genus comprising two species native to Southeast Asia: the banded linsang (Prionodon linsang) and the spotted linsang (Prionodon pardicolor). Prionodon is considered a sister taxon of the Felidae.

Eared seal

An eared seal or otariid or otary is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds. They comprise 15 extant species in seven genera (another species became extinct in the 1950s) and are commonly known either as sea lions or fur seals, distinct from true seals (phocids) and the walrus (odobenids). Otariids are adapted to a semiaquatic lifestyle, feeding and migrating in the water, but breeding and resting on land or ice. They reside in subpolar, temperate, and equatorial waters throughout the Pacific and Southern Oceans and the southern Indian and Atlantic Oceans. They are conspicuously absent in the north Atlantic.

The words 'otariid' and 'otary' come from the Greek otarion meaning "little ear", referring to the small but visible external ear flaps (pinnae), which distinguishes them from the phocids.

Ferret-badger

Ferret-badgers are the five species of the genus Melogale, which is the only genus of the monotypic mustelid subfamily Helictidinae.

Bornean ferret-badger (Melogale everetti)

Chinese ferret-badger (Melogale moschata)

Javan ferret-badger (Melogale orientalis)

Burmese ferret-badger (Melogale personata)

Vietnam ferret-badger (Melogale cucphuongensis)

Fur seal

Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family Otariidae. They are much more closely related to sea lions than true seals, and share with them external ears (pinnae), relatively long and muscular foreflippers, and the ability to walk on all fours. They are marked by their dense underfur, which made them a long-time object of commercial hunting. Eight species belong to the genus Arctocephalus and are found primarily in the Southern Hemisphere, while a ninth species also sometimes called fur seal, the northern fur seal (Callorhinus ursinus), belongs to a different genus and inhabits the North Pacific.

Galerella

Galerella is a genus of the mongoose family (Herpestidae) native to Africa and commonly called the slender mongooses.There are four or five species in this genus, with more than 30 subspecies.

Four of the species have long been established:

A recent addition is the black mongoose, Galerella nigrata, which now is considered a separate species by many scientists, following genetic analysis. It was previously seen as a variant of Galerella sanguinea.

Gaston (seal)

Gaston is the name of a brown fur seal that lived in Prague Zoo in years 1991-2002. He became famous during the 2002 European floods when he escaped from the zoological garden, when the rising waters of the Vltava river flooded his tank at Prague zoo. He swam more than 300 km (190 mi) from Prague to Dresden (Germany) on rivers Vltava and Elbe. He was recaptured north of Dresden and subsequently died due to exhaustion and infection.Gaston was memorialized with a statue in the Prague Zoo.

Haussa genet

The Haussa genet (Genetta thierryi) is a genet species native to West African savannas. It is listed as Least Concern on the IUCN Red List.Haussa genets have been sighted in Senegal's wooded steppes, in moist woodlands in Guinea-Bissau, and in rainforest in Sierra Leone, Ghana and Ivory Coast.

Long-nosed mongoose

The long-nosed mongoose (Herpestes naso) is a mongoose native to Cameroon, Republic of the Congo, The Democratic Republic of the Congo, Equatorial Guinea, Gabon, Kenya, Nigeria, and Tanzania.

Lutrogale

Lutrogale is a genus of otters, with only one extant species—the smooth-coated otter.

Mephitis (genus)

The genus Mephitis is one of several genera of skunks, which has two species and a North American distribution.

Mustelinae

Mustelinae is a subfamily of family Mustelidae, which includes weasels, ferrets amd minks.It was formerly defined in a paraphyletic manner to also include wolverines, martens, and many other mustelids, to the exclusion of the otters (Lutrinae).

Narrow-striped mongoose

The narrow-striped mongoose (Mungotictis decemlineata) is a member of the family Eupleridae, subfamily Galidiinae and endemic to Madagascar. It inhabits the Madagascar dry deciduous forests of western and southwestern Madagascar, where it lives from sea level to about 125 m (410 ft) between the Tsiribihina and Mangoky rivers. In Malagasy it is called bokiboky (pronounced "Boo-ky Boo-ky").

Nyctereutes

Nyctereutes is an Old World genus of the family Canidae, consisting of just one living species, the raccoon dog of East Asia. Nyctereutes appeared about 9.0 million years ago (Mya), with all but one species becoming extinct before the Pleistocene.

Native to East Asia, the raccoon dog has been intensively bred for fur in Europe and especially in Russia during the twentieth century. Specimens have escaped or have been introduced to increase production and formed populations in Eastern Europe. It is currently expanding rapidly in the rest of Europe, where its presence is undesirable because it is considered to be a harmful and invasive species.

Paradoxurinae

The Paradoxurinae are a subfamily of the viverrids that was denominated and first described by John Edward Gray in 1864.Pocock subordinated the oriental genera Paradoxurus, Paguma and Arctictis to this subfamily.

West African oyan

The West African oyan (Poiana leightoni), also known as the West African linsang, is a linsang species native to the Upper Guinean forests in West Africa.

It is one of the least known small carnivores in Africa.

Extant Carnivora species

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