African clawless otter

The African clawless otter (Aonyx capensis), also known as the Cape clawless otter or groot otter, is the second-largest freshwater species of otter. African clawless otters are found near permanent bodies of water in savannah and lowland forest areas. They range through most of sub-Saharan Africa, except for the Congo River basin and arid areas.[2] They are characterized by partly webbed and clawless feet, from which their name is derived.

African clawless otter[1]
Aonyx capensis, male, Shamvura
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Genus: Aonyx
Species:
A. capensis
Binomial name
Aonyx capensis
(Schinz, 1821)
African Clawless Otter area
African clawless otter range

Taxonomy

Aonyx capensis is a member of the weasel family (Mustelidae) and of the order Carnivora. The earliest known species of otter, Potamotherium valetoni, occurred in the upper Oligocene of Europe: A. capensis first appears in the fossil record during the Pleistocene.[3] Aonyx is closely related to the extinct giant Sardinian otter, Megalenhydris.

Subspecies

Mammal Species of the World lists six subspecies of Aonyx capensis:[1]

  • A. c. capensis (Schinz, 1821)
  • A. c. hindei (Thomas, 1905)
  • A. c. meneleki (Thomas, 1903)
  • A. c. congicus (Lönnberg, 1910)
  • A. c. microdon (Pohle, 1920)
  • A. c. philippsi (Hinton, 1921)

However, some authorities[2][3] consider the Congo/Cameroon clawless otter to be a separate species (A. congicus). Under this view, only the first three of the above list would be subspecies of A. capensis.

Description

African clawless otters have thick, smooth fur with almost silky underbellies. Chestnut in color, they are characterized by white facial markings that extend downward towards their throat and chest areas. Paws are partially webbed with five fingers, and no opposable thumbs. All lack claws except for digits 2, 3, and 4 of the hind feet. Their large skulls are broad and flat, with relatively small orbits and short rostra. Molars are large and flat, used for crushing of prey. Male otters are slightly larger than females on average. Adults are 113–163 cm (45–64 in) in length, including their tails that comprised about a third of their length. Weights can range from 10–36 kg (22-80 lbs), with most otters averaging between 12 and 21 kg (26-46 lbs).[4][5] Despite being closely related to the oriental small-clawed otter, the African clawless otter is often twice as massive as that relatively diminutive mustelid.

Habitat

African clawless otters can be found anywhere from open coastal plains, to semiarid regions, to densely forested areas. Surviving mostly in southern Africa, the otters live in areas surrounding permanent bodies of water, usually surrounded by some form of foliage. Logs, branches, and loose foliage greatly appeal to the otter as this provides shelter, shade, and great rolling opportunities. Slow and rather clumsy on land, they build burrows in banks near water, allowing for easier food access and a quick escape from predators. In the False Bay area of the Cape Peninsula, they have been observed scavenging along beaches and rocks and hunting in shallow surf for mullet. They are mainly nocturnal in urban areas and lie up during the day in quiet, bushy areas.

Reproduction

Females give birth to litters containing two to five young around early spring. Mating takes place in short periods throughout the rainy season in December. Afterwards, both males and females go their separate ways and return to their solitary lives once more. Young are raised solely by the females. Gestation lasts around two months (63 days). Weaning takes place between 45 and 60 days, with the young reaching full maturity around one year of age.

Diet

The diet of Aonyx capensis primarily includes water-dwelling animals, such as crabs, fish, frogs and worms. They dive after prey to catch it, then swim to shore again, where they eat. Their fore paws come in handy as searching devices and are great tools for digging on the muddy bottoms of ponds and rivers, picking up rocks and looking under logs. Extremely sensitive whiskers (vibrissae) are used as sensors in the water to pick up the movements of potential prey.

Behavior

Cape Clawless Otter
African clawless otter in Toledo Zoo, Ohio

Though mostly solitary animals, African clawless otters will live in neighboring territories of family groups of up to five individuals. Each still having its own range within that territory, they mostly keep to themselves unless seeking a mate. Territories are marked using a pair of anal glands which secrete a particular scent. Each otter is very territorial over its particular range.

The African clawless otter spends its days swimming and catching food. They return to underground burrows (holts) for safety, cooling or a rubdown using grasses and leaves. Mainly aquatic creatures, their tails are used for locomotion and propel them through the water. They are also used for balance when walking or sitting upright.

Predation

Quick in the water and burrowing on land, A. capensis does not have many predators. Its greatest threat comes from the python, which will often lay and wait near or in the water. Other predators would include the crocodile and fish eagles. If threatened, a high-pitched scream is emitted to warn neighboring otters and confuse a predator.

Thermoregulation

Living in Africa, environments can become very hot. Staying cool means spending time in the water, and using burrows as a way to escape the highest temperatures of the day. To stay warm, on the other hand, the otters depend solely on their thick fur. Guard hairs cover the body, acting as insulation. Since the otter lacks an insulating layer of body fat, its only means of warmth is provided by its thick coat of fur.

Economic impact

The biggest threat to African clawless otters comes from humans. Aonyx specimens will often forage in man-made fisheries and may be hunted or become entangled in nets. Overfishing by humans may reduce the food supply available to otters. They are sometimes hunted for their thick, soft pelts, which humans use in forms of clothing. In forested areas, logging may be a major threat, since erosion leads to greatly increased turbidity in rivers which can in turn greatly reduce the populations of fish on which the otters depend. This may well be a far greater threat to otters than hunting. The Otter Trail is a hiking trail in South Africa named after the African clawless otter, which is found in this area. Otters along the trail are protected, as it falls within the Tsitsikamma National Park.

References

  1. ^ a b Wozencraft, W.C. (2005). "Aonyx capensis". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 532–628. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ a b c Hoffmann, M. (2008). "Aonyx capensis". IUCN Red List of Threatened Species. Version 2014.3. International Union for Conservation of Nature. Retrieved 9 April 2015.
  3. ^ a b Larivière, Serge (5 June 2001). "Aonyx capensis" (PDF). Mammalian Species. 671: 1–6. doi:10.1644/1545-1410(2001)671<0001:ac>2.0.co;2.
  4. ^ African Clawless Otter. Archived 2011-08-30 at the Wayback Machine Arkive.org. 2011.
  5. ^ African Clawless Otter. The Animal Files. 2011.

Further reading

External links

Aonyx

Aonyx is a genus of otters, containing only one species, the African clawless otter, and two well-known subspecies, the Cape clawless otter and the Cameroon clawless otter. Sometimes also the Oriental small-clawed otter, Amblonyx cinerea is counted in this genus.

The word aonyx means "clawless", derived from the prefix a- ("without") and onyx ("claw/hoof").

Aonyx capensis capensis

The Cape clawless otter (Aonyx capensis capensis), sub-species of (A. capensis) or generally referred to as African clawless otter is found in Sub-Saharan Africa near permanent bodies of freshwater or can be seen to occupy along the sea coast (2). The Cape clawless otter is the largest of the Old World otters and the 3rd largest of all the otters after the giant otter (Pteronura brasiliensis) and the sea otter (Enhydra lutris).

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.

Cameroon clawless otter

The Cameroon clawless otter (Aonyx capensis congicus) is a subspecies of the African clawless otter in the family Mustelidae. It is found in Cameroon, Republic of the Congo, Democratic Republic of the Congo, Gabon, and possibly Angola, Burundi, Central African Republic, Equatorial Guinea, Nigeria, Rwanda, or Uganda. Its natural habitats are subtropical or tropical moist lowland forest, subtropical or tropical mangrove forest, subtropical or tropical swamps, subtropical or tropical moist montane forest, subtropical or tropical moist shrubland, subtropical or tropical seasonally wet or flooded lowland grassland, rivers, intermittent rivers, shrub-dominated wetlands, swamps, freshwater lakes, intermittent freshwater lakes, freshwater marshes, intermittent freshwater marshes, freshwater spring, inland deltas, saline lakes, intermittent saline lakes, saline marshes, intermittent saline marshes, shallow seas, subtidal aquatic beds, rocky shores, sandy shores, estuarine waters, intertidal flats, intertidal marshes, coastal saline lagoons, coastal freshwater lagoons, water storage areas, ponds, aquaculture ponds, seasonally flooded agricultural land, and canals and ditches. It is threatened by habitat loss.

Very little is known about this species. It is a large otter and found only in the mid-part of Africa, in the tropical belt. It is believed to spend much more time on land than other otters. Congo clawless otters are one of 13 species of otters in the carnivore family Mustelidae. Other members of this family include weasels, wolverines, and ferrets. An individual otter maintains a territory. Otters mark their territories with scent, and fervently patrol and defend their territories.

Kakamega Forest

Kakamega Forest is a tropical rainforest situated in the Kakamega and Kisumu Counties of Kenya, northwest of the capital Nairobi, and near to the border with Uganda. It is Kenya's only tropical rainforest and is said to be Kenya's last remnant of the ancient Guineo-Congolian rainforest that once spanned the continent.

Kiang West National Park

Kiang West National Park is one of the largest and most important wildlife reserves in the Gambia. It was declared a national park in 1987 and is managed by the Gambia Department of Parks and Wildlife Management.

King genet

The king genet (Genetta poensis) is a small carnivoran native to the Republic of the Congo, Equatorial Guinea, Liberia, Ghana and Côte d'Ivoire. As it has not been recorded since 1946, it is listed as Data Deficient on the IUCN Red List. It probably inhabits only tropical rainforest.

Lake Kwania

Lake Kwania is in the districts of Lira, Apac and Amolatar in the Northern Region of Uganda. It is part of a large wetland along the White Nile (Victoria Nile) between Lake Victoria and Lake Albert. The wetland, which includes Lake Kwania, the even larger Lake Kyoga, and other water bodies and swamps, consists of about 3,420 square kilometres (1,320 sq mi) of open water and about 2,180 square kilometres (840 sq mi) of permanent swamps. Of this total, Lake Kwania accounts for 540 square kilometres (210 sq mi), about 16 percent, of the open water.The lake is heavily fished for Nile tilapia and Nile perch, introduced species that caused declines in native fish populations after the mid-1950s. By the late 1960s, the introduced species made up about 80 percent of the commercial catch from Lake Kyoga, Kwania's near neighbor. Although civil unrest, overfishing, and infestations of water hyacinth (later brought under control) at times curtailed the fishing, by the mid-1990s Lake Kwania had 34 landing sites and a fleet of about 1,500 planked canoes operated by about 4,500 fishers.

Lake Mutanda

Lake Mutanda is a small freshwater lake in Uganda.

Lutrogale

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

Mustelidae

The Mustelidae (; from Latin mustela, weasel) are a family of carnivorous mammals, including weasels, badgers, otters, ferrets, martens, mink, and wolverines, among others. Mustelids are diverse and the largest family in the order Carnivora, suborder Caniformia. Mustelidae comprises about 56-60 species across eight subfamilies.

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).

Neophoca

Neophoca is a genus of the family Otariidae (sea lions and fur seals) of order Carnivora. It is combined by some taxonomists with the genus Phocarctos, the (extant) New Zealand sea lion. Only one species survives:

N. cinerea: Australian sea lion. Most subpopulations are small and genetically isolated.Extinct species:

N. palatina, known from a skull found in New Zealand

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.

Otter

Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the weasel family Mustelidae, which also includes badgers, honey badgers, martens, minks, polecats, and wolverines.

Paradoxurus

Paradoxurus is a genus within the viverrid family that was denominated and first described by Frédéric Cuvier in 1822. As of 2005, this genus was defined as comprising three species native to Southeast Asia:

the Asian palm civet (P. hermaphroditus)

the golden palm civet (P. zeylonensis)

the brown palm civet (P. jerdoni)In 2009, it was proposed to also include the golden wet-zone palm civet (P. aureus), the Sri Lankan brown palm civet (P. montanus) and the golden dry-zone palm civet (P. stenocephalus), which are endemic to Sri Lanka.

Prionailurus

Prionailurus is a genus of spotted, small wild cats native to Asia. Forests are their preferred habitat; they feed on small mammals, reptiles and birds, some also on aquatic wildlife.

River Gambia National Park

River Gambia National Park is a national park in the Gambia.

Extant Carnivora species

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