Arctocephalus pusillus (Cape fur seal, South African fur seal)

Kaapse pelsrob [Afrikaans]; intini yaselwandle [isiXhosa]; imvu yamanzi [isiZulu]; lenyedi [Sepedi]; tau ya metsi, tau ya lewatle, tlou ya metsi, dou ya lewade [Sesotho]; imvu yemanti [siSwati]; sili ya vhukuse [Tshivenda]

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Deuterostomia > Chordata > Craniata > Vertebrata (vertebrates)  > Gnathostomata (jawed vertebrates) > Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class: Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) > Reptiliomorpha > Amniota > Synapsida (mammal-like reptiles) > Therapsida > Theriodontia >  Cynodontia > Mammalia (mammals) > Placentalia (placental mammals) > Laurasiatheria > Ferungulata > Ferae > Carnivora > Family: Otariidae (eared seals, sealions)

Cape fur seal colony at Cape Cross, Namibia. [photo Duncan Robertson ©]

South African fur seal. [photo Jeff Poklen ©]

Identification

The Cape fur seal is the most common species to be found in southern African waters. Like all seals they have streamlined spindle shaped bodies, with limbs modified as flippers. Males (called bulls) are much larger than females and have thick powerful necks; they have thick fur coats that are uniform in colour varying from dark brown to a lighter golden brown. Cows tend to be a more brownish-grey in color. The pelt consists of guard hairs and a thick, woolly underfur and is essentially waterproof with insulation provided by the air trapped in the coat. The bulls have coarse outer hair on the neck and head. The small ears have scroll like external flaps. When moving on land the hindlimbs are moved forward under their bodies to walk, the front flippers bend out sideways and slightly backwards. While swimming the propulsion is provided by the front flippers with the hindlimbs having no active role.

Size

Body length 2.2 m (male), 1.6 m (female); weight range 190kg (male), 75 kg (female)

Dental Formula

 ICPC = 36

Distribution and habitat

Marine, occurring from Namibia on the west coast to East London on the east coast. Breeds on offshore islands and in large mainland colonies on the arid west coast.  

Food

Consists mainly of shoaling pelagic fish such as pilchard, hake, Cape mackerel, and snoek. Also eats squid and crustaceans. In some areas their diet also includes African penguins.Cape fur seals are generalist feeders catching a wide variety of prey and are expected to feed on locally abundant prey species. Large prey is eaten on the surface while smaller items are eaten underwater. Cape fur seals forage within 220 km of their colony.

Reproduction

Cape fur seal cow feeding her pup at the Cape Cross colony, Namibia. [photo Duncan Robertson ©]

Gregarious, gathering on sandy beaches, rocks and coastal islands. Mature bulls arrive at the breeding colonies in Mid-October. They establish territories and defend them against rivals. The cows arrive a few weeks later to give birth to a single pup (after a gestation period of a year). The bulls establish a harem of several cows. Mating takes place about a week after the cow has given birth. After giving birth, females alternate foraging trips to sea with suckling periods. Each pup has a distinctive call and scent that enables its mother to locate and recognize it in the rookery when she returns from feeding at sea. Similarly the pup also recognizes its mother’s call and smell. The pup will be suckled for 8 – 10 months, although for at least 6 months of this time it will also be foraging on its own, learning the hunting skills it requires as an adult. The breeding colonies break up and disperse before the end of December. Life span: Unknown.

Conservation

The uncontrolled exploitation of the Cape Fur Seal led to a serious reduction in population numbers. In 1893 they were protected by an Act of the Cape Parliament and harvesting was controlled until 1990 when it was finally prohibited. The protection of the seals and the halt to all “sealing” activities resulted in the recovery of the populations. Sealing continues in Namibia where it is still permitted. Seals do conflict with the fishing industry as they steal fish off the lines and also break nets. Fishermen maintain that seals seriously reduce the local fish populations and consequently their catches. Currently while numbers continue to increase their conservation status in not regarded as threatened. However, the effect of declining pelagic fish stocks on the seal populations are a concern and the subject of several current research projects.