The African clawless otter (''Aonyx capensis''), also known as the Cape clawless otter or groot otter, is the second-largest freshwater

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 Mustelidae family, which also includes we ...

species. It inhabits permanent water bodies in savannah and lowland forest areas through most of

sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...

. 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").

Taxonomy

''Aonyx capensis'' is a member of the weasel family (

Mustelidae The Mustelidae (; from Latin ''mustela'', weasel) are a family of carnivorous mammals, including weasels, badgers, otters, ferrets, martens, minks and wolverines, among others. Mustelids () are a diverse group and form the largest family in th ...

) and of the order

Carnivora Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...

. The earliest known species of otter, ''

Potamotherium ''Potamotherium'' ('river beast') an extinct genus of caniform carnivoran from the Miocene epoch of France and Germany. It has been previously assigned to the mustelid family, but recent work suggests that it represents a primitive relative of pi ...

valetoni'', occurred in the upper Oligocene of Europe: ''A. capensis'' first appears in the fossil record during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

. ''Aonyx'' is closely related to the extinct giant

Sardinia Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label= Algherese and Catalan) is the second-largest island in the Mediterranean Sea, aft ...

n otter, '' Megalenhydris''.

Subspecies

Mammal Species of the World ''Mammal Species of the World: A Taxonomic and Geographic Reference'' is a standard reference work in mammalogy giving descriptions and bibliographic data for the known species of mammals. It is now in its third edition, published in late 2005, ...

'' lists six subspecies of the African clawless otter: * ''A. c. capensis'' (Schinz, 1821) * ''A. c. hindei'' (Thomas, 1905) * ''A. c. meneleki'' (Thomas, 1903) * ''A. c. microdon'' (Pohle, 1920) * ''A. c. philippsi'' (Hinton, 1921) Until recently the

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

was considered a subspecies as well, but recent authorities treat it as a separate species ''A. congicus''.

Description

The African clawless otter has a chestnut-coloured thick, smooth fur with almost silky underbellies. It is characterized by white facial markings that extend downward towards its throat and chest areas. Paws are partially webbed with five fingers, but without opposable thumbs. All lack claws except for digits 2, 3, and 4 of the hind feet. Its large skull is broad and flat, with a relatively small orbit and a short

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is ...

. Molars are large and flat, used for crushing of prey. Male otters are slightly larger than females on average. Adults are in length, including their tails that comprised about a third of their length. Weights range from , with most otters averaging between . They are the third largest otter on average after the

sea otter The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel family, but among the smal ...

and giant otter and probably the third largest extant mustelid appearing to slightly outrival the

wolverine The wolverine (), (''Gulo gulo''; ''Gulo'' is Latin for " glutton"), also referred to as the glutton, carcajou, or quickhatch (from East Cree, ''kwiihkwahaacheew''), is the largest land-dwelling species of the family Mustelidae. It is a musc ...

, hog badger and

European badger The European badger (''Meles meles''), also known as the Eurasian badger, is a badger species in the family Mustelidae native to almost all of Europe. It is classified as least concern on the IUCN Red List as it has a wide range and a large stab ...

in mean body mass.African Clawless Otter.
The Animal Files. 2011. Despite being closely related to the

Asian small-clawed otter The Asian small-clawed otter (''Aonyx cinereus''), 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 w ...

, the African clawless otter is often twice as massive as that relatively diminutive mustelid.

Distribution and habitat

African clawless otters can be found anywhere from open coastal plains, to semiarid regions, to densely forested areas. Surviving mostly in southern

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, 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 Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

in urban areas and lie up during the day in quiet, bushy areas.

Behaviour and ecology

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 gland Anal may refer to: Related to the anus *Related to the anus of animals: ** Anal fin, in fish anatomy ** Anal vein, in insect anatomy ** Anal scale, in reptile anatomy *Related to the human anus: ** Anal sex, a type of sexual activity involving ...

s 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 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.

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 (

vibrissa Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser ...

e) are used as sensors in the water to pick up the movements of potential prey.

Predation

Quick in the water and burrowing on land, the African clawless otter does not have many predators. Its greatest threat comes from the python, which will often lie in wait near or in the water. Other predators would include the

crocodile Crocodiles (family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to include all extant me ...

and

African fish eagle The African fish eagle (''Haliaeetus vocifer'') or the African sea eagle, is a large species of eagle found throughout sub-Saharan Africa wherever large bodies of open water with an abundant food supply occur. It is the national bird of Malawi, Na ...

. 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.

Threats

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 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 Mustelidae family, which also includes wea ...

is a hiking trail in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

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 The Tsitsikamma National Park is a protected area on the Garden Route, Western Cape and Eastern Cape, South Africa. It is a coastal reserve well known for its indigenous forests, dramatic coastline, and the Otter Trail. On 6 March 2009 it was ...

References

External links

Animal Diversity Web

{{DEFAULTSORT:otter, clawless, African

African clawless otter The African clawless otter (''Aonyx capensis''), 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-S ...

Mammals of Sub-Saharan Africa Carnivorans of Africa