Arctocephalus pusillus has two sub-species, A. p. pusillus and A. p. doriferus, which are separated by the ocean between Africa and Australia. Skull characteristics of the two subspecies are similar enough to place them in one species. A notable difference between the two is the crest between the mastoid process and the jugular process of the exoccipital, which is proportionately larger in A. p. pusillus (King, 1983).
Males of the South African or cape fur seal subspecies, A. p. pusillus, are an average of 2.3 meters in length and weigh from 200 to 350 kg (King 1983). Their coat is gray or black in color and is lighter on the underside (King 1983, Schliemann 1990). Female African fur seals are smaller, weighing an average of 120 kg (King 1983) and measuring an average of 1.8 meters long (Schliemann 1990). Their coats are brown with lighter shading on the underside.
Males of the subspecies A. p. doriferus, the Australian fur seal, weigh anywhere from 218-360 kg and are 2-2.2 meters in length (King 1983). Their coats are a gray-brown and they have a thick mane about their neck region which is slightly lighter (King, 1983). Female Australian fur seals vary greatly in size, weighing between 36 and 110 kg and measuring between 1.2 and 1.8m in length (King 1983, Schliemann 1990). Their coat is a silver-gray with a yellow colored throat and brown underside.
Range mass: 36 to 360 kg.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average lifespan
Status: wild: 18.0 years.
Both subspecies of A. pusillus spend most of their year at sea but not too far from land. A maximum of 160 km from land is recorded but is not a common (King, 1983). Breeding occurs on the mainland or small islands in the sand or rocks (King, 1983). Both subspecies prefer small rocky islands for mating and pupping.
Aquatic Biomes: coastal
Arctocephalus pusillus pusillus can be found along the southern and southwestern coast of Africa. They are commonly spotted throughout Namibia and as far east as Port Elizabeth (Schliemann 1990, King 1983).
Arctocephalus pusillus doriferus can be found along the southern and southeastern coasts of Australia. They are commonly spotted in places like Victoria, New South Wales, Tasmania and scattered islands (Schliemann 1990, King 1983).
Biogeographic Regions: ethiopian (Native ); australian (Native ); indian ocean (Native ); atlantic ocean (Native )
Stomach contents of South African fur seals indicate that fish make up about 70% of their diet, squid 20%, crab 2% (Schliemann, 1990). The remaining portion is composed of other crustaceans, cephalopods and sometimes birds (King 1983, Schliemann 1990). Australian fur seals commonly eat squid, octopus, fish and lobsters, along with other crustaceans and cephalopods (King 1983, Schliemann 1990). Like most air-breathing marine mammals A. pusillus finds its food in the ocean. In order to do so it must store oxygen and swim below the surface to the depth at which its particular prey is located. Both subspecies of A. pusillus dive for their food but they each occupy different depth niches in their respective locations. South African fur seals are surface divers with an average dive of about 45 meters and 2.1 minutes although they can dive as deep as 204 meters and for as long as 7.5 minutes when necessary (Riedman, 1990). While there is extensive overlap, Australian fur seals generally feed at a much lower depths. Their average dive is about 120 meters (Schliemann, 1990) and they commonly go as deep as 200 meters (Riedman, 1990).
Sealing has been common for centuries. Seals are taken for their pelts, their blubber, or their meat. Currently there are seasons for hunting different classes of the South African fur seal, but this is controversial. Seal pups are valued for their softer fur and male genitalia is taken and sold as an aphrodisiac. The Australian fur seal is protected and is not legally hunted by humans today, although it was hunted for meat in the past (King, 1983).
South African fur seals are more abundant than are Australian fur seals. Both are at the mercy of poachers, even though there are legal hunting seasons for South African fur seals. Much of the poaching danger is in the form of fishermen and large fishing corporations who believe the seals to be jeopardizing their livelihood by stealing from their nets. While this does occur it is believed to be exaggerated by those in the fishing industry.
Humans are also inadvertently threatening these seals through pollution. Plastic, pieces of netting, and pieces of fishing line kill or injure thousands of these seals a year.
Non-human threats include killer whales and white sharks. Stingrays can cause some dangerous injuries. Pups left on the mainland are also sometimes taken by terrestrial predators, such as the black-backed jackal in South Africa.
US Federal List: no special status
CITES: appendix ii
IUCN Red List of Threatened Species: least concern
Perception Channels: tactile ; chemical
The breeding season for both subspecies of A. pusillus begins in the middle of October. At this time males haul out on shore at the breeding grounds, or rookeries, to establish territories by displays, sparring, or actual battle. They do not eat again until they mate in November or December.
Females come ashore slightly later and also fight amongst each other for smaller territories in which to give birth. Female territories are always within male territories and females who are located on a certain male's territory become part of his harem. While harem sizes of both subspecies can reach as many as 50 females, or cows, the average size of the South African fur seal harem is 28 cows, the Australian fur seal harem averages 10 cows (Schliemann, 1990). Breeding occurs between the male and each of his harem members. While copulation occurs about 6 days after cows give birth to a single pup there is a delay in implantation of the blastocyst. In South African fur seals this delay is approximately 4 months while in Australian fur seals it is about 3 months (Riedman, 1990). Gestation in both subspecies averages 11.75 months (Riedman, 1990).
South African fur seal pups are anywhere from 4.5 to 7 kg and 60-70 cm at birth (King 1983), which occurs in late November or early December. The pups go through two different molts in their first year and a half. Their original coat is black and curly. This coat is replaced between 4 and 5 weeks with an olive-gray coat. The second molt takes place at about 13 months and replaces the olive-gray coat with a silver one which later fades in color (King 1983). Nursing in this subspecies begins immediately after birth and is continuous for the first six days. At this time the mother mates with her male harem leader and then begins going out to sea for food for a few days at a time. By the second month, however, she can be gone for up to two weeks before returning to feed the pup (King, 1983). At four to five months old pups begin supplementing their diet with crustaceans and fish. Lactation does continue, however, until the next pup is born. Pups begin swimming early and continually increase the amount of time that they can spend in the water. At seven months they can swim for two or three days at a time (King, 1983). Females become sexually mature at about 3 years and males may also follow this trend but are unable to establish territory at this time so do not usually mate until several years later (King, 1983).
Australian fur seal pups weigh 4.5 to 12.5 kg and measure 62-80 cm in length at birth. They are a silver-gray in color and their entire ventral side is yellow. Pups in this subspecies are usually born in early to middle December. As in South African fur seals, nursing begins right after birth and is continuous for the first week or so, until the mother mates again and goes out to sea for food. At this time, however, the Australian fur seal returns once every week to feed her pup (Riedman, 1990). By the eighth month of life Australian fur seals are eating some solid supplements although lactation continues until the next pup is born. The pups start swimming for prolonged periods also at the eighth month. Sexual maturity is widely varied within the subspecies. Females reach maturity any time between 3 and 6 years of age (King, 1983). Males probably reach maturity between four and five years of age but cannot hold a harem until they are closer to seven or eight years old (King, 1983).
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average birth mass: 6200 g.
Average gestation period: 368 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (male)
Sex: male: 1643 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1276 days.
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.
The brown fur seal is the largest and most robust member of the fur seals. It has a large and broad head with a pointed snout that may be flat or turned up slightly.[3] 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.[3] 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).[4] Females are smaller, averaging 1.8 m (5.9 ft) in length and typically weighing 120 kg (260 lb).[5] 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).[6] Females are 1.2–1.8 m (3.9–5.9 ft) length and weigh 36–110 kilograms (79–243 lb).[5]
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.[3] Pups are born black and molt to gray with a pale throat within 3-5 months.[3] The skull of the African subspecies has a larger crest between the mastoid process and the jugular process of the exoccipital.[5]
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.[3] The Australian fur seal lives in Bass Strait, at four islands off Victoria in southeastern Australia, and five islands off Tasmania.[3] 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.[3] 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.[5]
The African fur seal's diet is made of up to 70% fish, 20% squid, and 2% crab.[7] Also eaten are other crustaceans, cephalopods and sometimes birds.[5][7] 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.[8] The Australian fur seal mostly eats squid, octopus, fish, and lobsters.[5][7] 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.[9] The Australian subspecies generally feeds at lower depths, diving on average 120 m[7] and can reach as deep as 200 m.[9]
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.[10] Land-based predators include black-backed jackals, brown hyenas and occasionally lions[11] on the Skeleton Coast in Namibia. In addition, seagulls are thought to peck the eyes out of baby seals to render them helpless and disabled, as they begin to feast on their flesh.[12]
In False Bay, the seals employ a number of antipredatory strategies while in shark-infested waters, such as:
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.[14] 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.[15][16] 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.[17] Males can also differentiate neighboring males from stranger males, responding more aggressively to the vocalizations of strangers.[18] 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.[19][20]
Brown fur seals often gather into colonies on rookeries in numbers ranging from 500 to 1500, at least for the Australian subspecies.[5] 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.[9] 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.[9] Gestation for the brown fur seal typically lasts a year less a few days.[9]
After mating, females begin alternating brief periods of foraging at sea with several days ashore nursing their pups.[3] 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.[9] When left alone, pups gather in groups and play during the evening.[5] Pups are usually weaned at 4–6 months old.[3]
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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 humans 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.[21] 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.[22]
In January 2023, media reports indicated that seals have been attacking humans in South Africa, particularly in Cape Town area. Scientists believe it is due to the presence of a brain-altering poison in the fish they consume. The poison is affecting their behavior and making them more aggressive towards humans. Some attribute the aggressive behavior of the animals to the surge of toxic red tide algae, fueled by pollution and climate change. The incidents have increased in recent times, leading to concern and calls for further investigation.[23][24]
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.
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