Aonyx capensis capensis

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Cape clawless otter
Aonyx capensis ssp. capensis.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Genus: Aonyx
Species:
Subspecies:
A. c. capensis
Trinomial name
Aonyx capensis capensis
Schinz, 1821

The Cape clawless otter (Aonyx capensis capensis) is a subspecies of African clawless otter found in sub-Saharan Africa near permanent bodies of freshwater and along the seacoast. It is the largest of the Old World otters and the third largest otter after the giant otter (Pteronura brasiliensis) and the sea otter (Enhydra lutris). [1]

Contents

Physical description

The Cape clawless otter has a massive body and a stout tail for an otter. It reaches 72–91 cm in length and 12–21 kg. [2] The upper lips, sides of the face, neck, throat, belly, and edge of ears are all white while the rest of the coat is brown. [1] The eyes and ears are small and rounded. [1] The coat is dense with hairs that can reach 25 mm in length covering a layer of thick skin. [1] As noted by the name, the toes are clawless except for digits 2, 3, and 4 of the hind feet, which have small grooming claws. [1] The hind feet are partially webbed, but the front feet are not, the least interdigital webbing of all otters. [1] Notably, the skull is quite large, housing a larger brain in relation to its body. [3]

Taxonomy and phylogeny

As a subspecies of Aonyx capensis, Cape clawless otters are within the subfamily of Lutrinae (otters). The closest relatives to Aonyx capensis are the Asian small-clawed otter (Aonyx cinereus) and the smooth-coated otter (Lutrogale perspicillata). [3]

Range

The Cape clawless otter is found in freshwater habitats that range from South Africa northward to Ethiopia in the east and Senegal in the west. [1] This species is common in Eswatini, Guinea, Kenya, Liberia, Malawi, Mozambique, Senegal, South Africa, Tanzania, Zaire, and Zimbabwe. It is rare in Angola, Benin, Botswana, Burkina Faso, Chad, Guinea-Bissau, Ivory Coast, Sierra Leone and Uganda. It is very or extremely rare in the Central African Republic, Ethiopia, Ghana, Lesotho, Namibia, Niger, Nigeria, and Rwanda. [1] It is absent in ecosystems in the central African rain forest region of the Congo Basin where A. congicus, the Congo clawless otter, is found. [1]

Behavior

Cape clawless otters are primarily solitary creatures, but have been seen to travel in family groups. [1] Their density in freshwater habitats ideally reaches 1 otter per 2–3 km of stream. [1] During the day, they typically escape the heat of the sun by hiding in dense vegetation on islands or burrowing. [1] Burrows can reach up to 3 m in depth and have several entrances above or below water. [1] Dens or burrows include rolling places, spots on the ground where the otter rolls to dry its fur, as well as multiple sprainting sites. [1] Dens may be reused by several otters in a family group or at separate times. [1]

The breeding season starts around December and, with a gestation period of 63 days, litters can be born beginning in February. [1] Litter size is 1–3 pups that are born with pale, smoky-gray, wooly fur. [1] Eye-opening for the pups is seen in 16–30 days, after which pups are able to venture out of the den. [1] Weaning occurs at 45–60 days and the young become fully independent of the mother after 1 year. [1]

As with most otters, this species has an elaborate vocal repertoire that includes four main vocalizations: two whistles (one low-pitched and one high-pitched), a grunt, and a variable noise described as a "Hah!" to express anxiety. [1] Growls and snarls may be given as threats while humming-like noises may be used as a begging call in the pups. [1] Other sounds may include squeals, mewing, and snuffing noises.

When not hunting, they typically emerge from the water to rest upon the shore. Rolling and rubbing is done to dry and groom the fur or to scent-mark areas. [1] Otters usually bask in the sun or can return undercover to sleep. [1]

Walking on land is awkward for Cape clawless otters so they are observed to either walk slowly or do a seal-like trot. The tail can either be carried off the ground with its tip curving upwards, or dragged on the ground leaving a distinct trail. [1] These otters are able to carry objects or prey while walking on land by holding them against the chest with one paw while hobbling on three legs. [1] Carrying offspring on land may result in the female using both front feet to carry the young and then hobbling on its back legs. [1] Due to their awkwardness on land, Cape clawless otters typically spend most of their time traveling in the water. [1]

Feeding

In freshwater habitats, the main sources of food are crabs, frogs, insects, and fish. [1] Although crabs are available in all of their habitats, other prey in their diet may vary seasonally and change with prey availability. [1] Due to this seasonal change, the Cape clawless otter usually is seen to consume more fish in the winter (10–30%) than in the summer (0–10%). [1] Predation on waterfowl is rarely seen, but in the winter theyt have been seen to kill domestic ducks, geese, coots, and swans. [1]

Conservation status

The Cape clawless otter is not under severe pressure and its conservation status is Red List Category Near Threatened, as assessed in 2014 by the IUCN. [4] Human conflict with this species is mainly from changes in habitat due to fishing, water pollution, agriculture run-off, and the introduction of Louisiana crayfish, which has altered the prey base in the otter's ecosystem. [4] Cape clawless otters can be hunted for their pelts, used for medicinal purposes, and in some areas killed as a perceived competitor for fish. [4] This species is legally protected by the IUCN, but extra efforts towards awareness and protected areas are highly encouraged for local communities. [4] Natural predators of the Cape clawless otter include crocodiles and fish-eagles; however, most mortality is human-caused.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Otter</span> Subfamily of mammals (Lutrinae)

Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine. Lutrinae is a branch of the Mustelidae family, which includes weasels, badgers, mink, and wolverines, among other animals.

<span class="mw-page-title-main">Baikal seal</span> Species of freshwater seal

The Baikal seal, Lake Baikal seal or nerpa is a species of earless seal endemic to Lake Baikal in Siberia, Russia. Like the Caspian seal, it is related to the Arctic ringed seal. The Baikal seal is one of the smallest true seals and the only exclusively freshwater pinniped species. A subpopulation of inland harbour seals living in the Hudson Bay region of Quebec, Canada,, as well as the Saimaa ringed seal and the Ladoga seal, are also found in fresh water, but these seals are part of species that also have marine populations.

<span class="mw-page-title-main">Asian small-clawed otter</span> Species of mammal

The Asian small-clawed otter, also known as the oriental small-clawed otter and the small-clawed otter, is an otter species native to South and Southeast Asia. It has short claws that do not extend beyond the pads of its webbed digits. With a total body length of 730 to 960 mm, and a maximum weight of 5 kg (11 lb), it is the smallest otter species in the world.

<span class="mw-page-title-main">North American river otter</span> Species of semi-aquatic mammal

The North American river otter, also known as the northern river otter and river otter, is a semiaquatic mammal that lives only on the North American continent, along its waterways and coasts. An adult North American river otter can weigh between 5.0 and 14 kg. The river otter is protected and insulated by a thick, water-repellent coat of fur.

<span class="mw-page-title-main">Giant otter shrew</span> Species of mammal

The giant otter shrew is a semiaquatic, carnivorous afrotherian mammal. It is found in the main rainforest block of central Africa from Nigeria to Zambia, with a few isolated populations in Kenya and Uganda. It lives in streams, wetlands and slow flowing larger rivers. It is the only species in the genus Potamogale. Otter shrews are most closely related to the tenrecs of Madagascar.

<span class="mw-page-title-main">Eurasian otter</span> Species of carnivore

The Eurasian otter, also known as the European otter, Eurasian river otter, European river otter, common otter, and Old World otter, is a semiaquatic mammal native to Eurasia and Maghreb. The most widely distributed member of the otter subfamily (Lutrinae) of the weasel family (Mustelidae), it is found in the waterways and coasts of Europe, many parts of Asia, and parts of northern Africa. The Eurasian otter has a diet mainly of fish, and is strongly territorial. It is endangered in some parts of its range, but is recovering in others.

<span class="mw-page-title-main">Giant otter</span> Species of mammal

The giant otter or giant river otter is a South American carnivorous mammal. It is the longest member of the weasel family, Mustelidae, a globally successful group of predators, reaching up to 1.8 m. Atypical of mustelids, the giant otter is a social species, with family groups typically supporting three to eight members. The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial, and aggression has been observed between groups. The giant otter is diurnal, being active exclusively during daylight hours. It is the noisiest otter species, and distinct vocalizations have been documented that indicate alarm, aggression, and reassurance.

<span class="mw-page-title-main">Neotropical otter</span> Species of mammal

The Neotropical otter or Neotropical river otter is an otter species found in Mexico, Central America, South America, and the island of Trinidad. It is physically similar to the northern and southern river otter, which occur directly north and south of this species' range. Its head-and-body length can range from 36–66 centimetres (14–26 in), plus a tail of 37–84 centimetres (15–33 in). Body weight ranges from 5–15 kilograms (11–33 lb). Otters are members of the family Mustelidae, the most species-rich family in the order Carnivora.

<span class="mw-page-title-main">Marine otter</span> Species of South American mammal (Lontra felina)

The marine otter is a rare and relatively unknown South American mammal of the weasel family (Mustelidae). The scientific name means "feline otter", and in Spanish, the marine otter is also often referred to as gato marino: "marine cat". The marine otter only lives in saltwater, coastal environments and rarely ventures into fresh water or estuarine habitats. This saltwater exclusivity is unlike most other otter species, except for the almost fully aquatic sea otter of the North Pacific.

<i>Aonyx</i> Genus of carnivores

Aonyx is a genus of otters, containing three species, the African clawless otter, the Congo clawless otter, and the Asian small-clawed otter. The word aonyx means "clawless", derived from the prefix a- ("without") and onyx ("claw/hoof").

<span class="mw-page-title-main">Aquatic mammal</span> Mammal that dwells partly or entirely in bodies of water

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<span class="mw-page-title-main">Southern river otter</span> Species of semi-aquatic mammal

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<span class="mw-page-title-main">Pale fox</span> Species of carnivore

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<span class="mw-page-title-main">Spotted-necked otter</span> Species of carnivore

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<span class="mw-page-title-main">African clawless otter</span> Species of carnivore

The African clawless otter, also known as the Cape clawless otter or groot otter, is the second-largest freshwater otter species. It inhabits permanent water bodies in savannah and lowland forest areas through most of sub-Saharan Africa. It is characterised by partly webbed and clawless feet, from which their name is derived. The word 'aonyx' means clawless, derived from the prefix a- ("without") and onyx ("claw/hoof").

<span class="mw-page-title-main">Smooth-coated otter</span> Species of carnivore

The smooth-coated otter is a freshwater otter species from regions of South and Southwest Asia, with the majority of its numbers found in Southeast Asia. It has been ranked as "vulnerable" on the IUCN Red List since 1996, as it is threatened by habitat loss, pollution of wetlands and poaching for the illegal wildlife trade. As the common name indicates, its fur is relatively smooth, and somewhat shorter in length than that of other otter species.

<span class="mw-page-title-main">Congo clawless otter</span> Species of carnivore

The Congo clawless otter, also known as the Cameroon clawless otter, is a species in the family Mustelidae. It was formerly recognised as a subspecies of the African clawless otter.

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<span class="mw-page-title-main">Rietvlei Wetland Reserve</span> Nature reserve in Table View, Western Cape, South Africa.

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References

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  2. Somers, Michael J. (2004). "Habitat selection by the Cape clawless otter (Aonyx capensis) in rivers in the Western Cape Province, South Africa". African Journal of Ecology. 42 (4): 298–305. Bibcode:2004AfJEc..42..298S. doi:10.1111/j.1365-2028.2004.00526.x.
  3. 1 2 "ARKive - African clawless otter videos, photos and facts - Aonyx capensis". Archived from the original on 2011-08-30. Retrieved 2015-03-04.
  4. 1 2 3 4 "IUCN OSG - Aonyx capensis". Archived from the original on 2008-05-09. Retrieved 2015-03-04.