Animal Diversity Web

Ge­o­graphic Range

Aonyx capen­sis is the most widely dis­trib­uted otter species in Africa. Their home range is lim­ited to the African con­ti­nent, stretch­ing along the coast from South Africa to Ethiopia and across the con­ti­nent to Sene­gal. Un­like their close rel­a­tive Aonyx capen­sis con­g­ica, Aonyx capen­sis does not occur in the cen­tral African rain­for­est re­gion of the Congo basin. Aonyx capen­sis and A. capen­sis con­g­ica are sym­patric in Uganda and Rwanda. (Hoff­mann, 2010; Lar­ivière, 2001)

• Biogeographic Regions
• ethiopian
  • native

Habi­tat

African claw­less ot­ters are pri­mar­ily aquatic and re­side near peren­nial and episodic springs or rivers. Ma­rine pop­u­la­tions do occur if a source of fresh­wa­ter is nearby for drink­ing. These ot­ters pre­fer shal­low water with thick reed beds, which are home to sev­eral fa­vor­able prey such as crab and fish. On land, African claw­less ot­ters take shel­ter in un­der­ground bur­rows, under rocks, roots, or dense veg­e­ta­tion. Dens have been found from sea level to 1200 m in el­e­va­tion. Dens are used for rest­ing, play­ing, eat­ing, defe­cat­ing, and giv­ing birth and are shared by mul­ti­ple ot­ters. African claw­less ot­ters have been known to dig bur­rows in the sand up to 3 m deep, with en­trances to the den above and below the water sur­face. Bur­rows typ­i­cally con­tain a nest made of grass or other veg­e­ta­tion. Dens are never far­ther than 50 m from shore or 15 m from fresh­wa­ter. They are usu­ally close to abun­dant food sup­plies and densely veg­e­tated areas. African claw­less ot­ters do not typ­i­cally dive far­ther than 1.5 m below the sur­face of the water. (Lar­ivière, 2001; Nel and Somers, 2007)

• Habitat Regions
• tropical
• terrestrial
• saltwater or marine
• freshwater

• Terrestrial Biomes
• savanna or grassland
• forest
• rainforest

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• temporary pools
• coastal
• brackish water

• Other Habitat Features
• riparian
• estuarine

• Range elevation

  0 to 1200 m

  0.00 to 3937.01 ft

• Average depth

  1.5 m

  4.92 ft

Phys­i­cal De­scrip­tion

African claw­less ot­ters are the largest Old World otter species and 3rd largest species of otter over­all. Their head and body length ranges from 762 mm to 880 mm. Their tail mea­sures 465 mm to 515 mm long and is typ­i­cally stout and ta­pered. They weigh be­tween 10 and 22 kg. Males are slightly heav­ier and longer than fe­males. Their thick shiny coats are col­ored dark brown ex­cept for dis­tinc­tive white col­or­ing on the upper lips, the sides of the face, neck, throat, belly, and lower ears. Otter pelage con­sists of two kinds of hair. The outer hairs, or guard hairs, mea­sure up to 25 mm in length. The un­der­coat, or fur, is white to off-white and is made of short (10 mm), fine, wavy hair. African claw­less ot­ters have long white whiskers on their cheeks, chin, and brows, which are used to de­tect prey in murky wa­ters. They are claw­less ex­cept for small groom­ing claws on hind dig­its 2, 3, and 4. Al­though their hind feet are par­tially webbed, they have the least amount of web­bing of all otter species. They have nim­ble forefeet with op­pos­able thumbs. Rough skin lines their palms and fin­gers and helps to grip slip­pery prey. African claw­less ot­ters have large skulls, mea­sur­ing 125 to 136 mm in length. They have a broad, flat­tened brain case and a small sagit­tal crest. Brain size is large com­pared to skull size, the ros­trum is short and broad, and zy­go­matic arches are slen­der. African claw­less ot­ters have large mo­lars, spe­cial­ized for crush­ing crus­taceans and fish skulls, and no cut­ting teeth. The shape of their mo­lars varies ge­o­graph­i­cally. They pos­sess a pair of anal scent glands are used for scent-mark­ing. Males’ fore­skin pro­trudes from their body but the penis re­sides be­neath their thick skin. Fe­males have two pairs of mam­mary glands on their ab­domen. (Lar­ivière, 2001; Nel and Somers, 2007)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  10.6 to 21 kg

  23.35 to 46.26 lb

• Range length

  730 to 880 mm

  28.74 to 34.65 in

Re­pro­duc­tion

Lit­tle is known about the mat­ing sys­tem of Aonyx capen­sis. (Lar­ivière, 2001)

Lit­tle is known of the mat­ing sys­tem of African claw­less ot­ters. Breed­ing oc­curs dur­ing the dry sea­son, which varies de­pend­ing on lo­ca­tion, and par­tu­ri­tion co­in­cides with the be­gin­ning of the rainy sea­son. Ges­ta­tion lasts ap­prox­i­mately 63 days. Lit­ters range in size from 1 to 3 pups, but as many as 5 pups per lit­ter have been re­ported for an­i­mals in cap­tiv­ity. At birth, pups weigh about 200 g and can grow to more than 1,400 g within 14 days. Pups are born al­tri­cial but open their eyes and leave their den after 16 to 30 days, and wean­ing oc­curs by 45 to 60 days after birth. They be­come in­de­pen­dent and sex­u­ally ma­ture by 1 year old. (Nel and Somers, 2007; Somers and Nel, 2003)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Breeding interval

  A. capensis breeds once a year.

• Breeding season

  Breeding occurs mainly during the dry season, though copulations may take place year round. .

• Range number of offspring

  1 to 5

• Average gestation period

  63 days

• Range weaning age

  45 to 60 days

• Average time to independence

  1 years

• Average age at sexual or reproductive maturity (female)

  1 years

• Average age at sexual or reproductive maturity (male)

  1 years

Lit­tle is known of parental care in African claw­less ot­ters. Moth­ers nurse their pups until they are 45 to 60 days old. Pups reach in­de­pen­dence by the end of their 1st year. (Lar­ivière, 2001)

• Parental Investment
• female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female

Lifes­pan/Longevity

African claw­less ot­ters live 10 to 12 years in the wild and ap­prox­i­mately 15 years in cap­tiv­ity. (Lar­ivière, 2001)

• Range lifespan
  Status: wild

  10 to 12 years

• Range lifespan
  Status: captivity

  15 (high) years

• Typical lifespan
  Status: wild

  10 to 14 years

• Average lifespan
  Status: captivity

  15 years

Be­hav­ior

African claw­less ot­ters are soli­tary and can be found in both fresh­wa­ter and ma­rine habi­tats. Groups com­posed of 4 to 6 in­di­vid­u­als, with 2 to 3 adults and 2 to 3 young, are oc­ca­sion­ally spot­ted and larger clans some­times form to for­age. These ot­ters are most ac­tive dur­ing dawn and dusk (i.e., cre­pus­cu­lar). Day­time is spent sleep­ing in bur­rows or dens. Nearly half of all dens are formed by nat­ural de­pres­sions or shel­ter­ing land­scape with the other half of dens con­structed by ot­ters dig­ging through soft sub­strates such as sand or mud. The floor of the den is often lined with veg­e­ta­tion. They spend a ma­jor­ity of their wak­ing hours swim­ming, hunt­ing, for­ag­ing, play­ing, and bask­ing in the sun. On land, these ot­ters ei­ther walk slowly or trot like a seal, some­times walk­ing over 7 km be­tween bod­ies of water. They swim by using their hind legs and tails for propul­sion while using their tails as rud­ders. (Lar­ivière, 2001; Nel and Somers, 2007; Somers and Nel, 2003)

African claw­less ot­ters do the ma­jor­ity of their hunt­ing in water. Shal­low water, ap­prox­i­mately 1.5 m deep, is pre­ferred for hunt­ing. They begin hunt­ing by sub­merg­ing their heads un­der­wa­ter and scan­ning for prey while using their forefeet to feel under rocks. They grab prey with their forefeet and bring it to the sur­face to eat. Small crabs are eaten while the otter is per­pen­dic­u­lar to the water’s sur­face, and large crabs are eaten while the otter lies on its back in order to catch pieces of food falling from its mouth. African claw­less ot­ters also dive for fish. Dives can last from 6 to 49 s, av­er­ag­ing 18 s per dive. Small fish are eaten in the water, and large fish are brought to shal­low water or the shore for con­sump­tion. Di­rectly after eat­ing, African claw­less ot­ters clean their faces with their forefeet. After hunt­ing bouts they may exit the water and dry off or spend time play­ing. They dry them­selves off by rolling and rub­bing their bod­ies against grass, rocks, or sand­bars and bask­ing in the sun. Young African claw­less ot­ters spend a sig­nif­i­cant amount of time play­ing and have been ob­served play-fight­ing, swim­ming, slid­ing on rocks, play­ing with their food, and even fetch­ing small peb­bles thrown into the water be­fore they hit the ground. (Lar­ivière, 2001; Nel and Somers, 2007; Somers and Nel, 2003)

• Key Behaviors
• natatorial
• nocturnal
• crepuscular
• motile
• sedentary
• solitary

• Range territory size

  49000 to 10625000 m^2

Home Range

African claw­less ot­ters have home ranges from 4.9 ha to 1062.5 ha. Most of their time is spent in a smaller core area rang­ing from 1.1 ha to 138.9 ha. (Nel and Somers, 2007)

Com­mu­ni­ca­tion and Per­cep­tion

African claw­less ot­ters make com­plex vo­cal­iza­tions, in­clud­ing low and high pitched whis­tles, grunts, and “hah” sounds thought to ex­press anx­i­ety. They also squeal, moan, and mew. The pur­pose of dif­fer­ent vo­cal­iza­tions is not well un­der­stood. These ot­ters de­mar­cate ter­ri­to­r­ial bound­aries with scant-marked fecal drop­pings called "spraints." Spraints are com­monly found sur­round­ing dens and occur most fre­quently dur­ing the mat­ing sea­son. A pair of anal scent glands are also used to com­mu­ni­cate through scent. (Lar­ivière, 2001; Somers and Nel, 2003)

• Communication Channels
• acoustic
• chemical

• Other Communication Modes
• pheromones
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

African claw­less ot­ters are pri­mar­ily car­ni­vores. In fresh­wa­ter habi­tats, their diet con­sists pri­mar­ily of crabs (Pota­mo­nautes); how­ever, they also eat frogs (Xeno­pus), in­sects (Co­pri­nae, Cy­clorhapha, Dytis­ci­dae, Nep­i­dae, Odonota, Scarabaei­dae), and var­i­ous species of fish, which make up more of the diet dur­ing win­ter when they are slowed by cold tem­per­a­tures and are eas­ier to catch. In ma­rine habi­tats, the diet of African claw­less ot­ters is mainly com­posed of fish. Ma­rine in­hab­i­tants also eat crab, Cape rock lob­sters, and abalone. African claw­less ot­ters have also been known to eat ducks, geese, coots, swans, drag­on­fly lar­vae, mol­lusks, rep­tiles, small birds, and shrews. (Lar­ivière, 2001; Nel and Somers, 2007; Somers and Nel, 2003)

• Primary Diet
• carnivore
  • piscivore
  • eats non-insect arthropods

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• fish
• insects
• mollusks
• aquatic crustaceans

Pre­da­tion

African claw­less ot­ters are oc­ca­sion­ally eaten by Nile croc­o­diles and fish-ea­gles. Their most dan­ger­ous preda­tors are hu­mans. Their bi-col­ored pelage helps cam­ou­flage them with in the water and on land. They are agile swim­mers that can often es­cape po­ten­tial preda­tors while in the water. While on land, how­ever, they are par­tic­u­larly vul­ner­a­ble to pre­da­tion. (Lar­ivière, 2001)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • Nile crocodile, (Crocodilus niloticus)
  • fish eagle, (Haliaetus vocifer)
  • humans, (Homo sapiens)

Ecosys­tem Roles

African claw­less ot­ters are preda­tors of crabs, fish, frogs, and in­sects. They are par­a­sitized by sev­eral species of flat­worm, in­clud­ing Baschkirovit­rema in­cras­sa­tum, Cli­nos­to­mum pyri­forme, and Prud­hoella rhode­sien­sis. In ad­di­tion, var­i­ous species of round­worm, in­clud­ing Cloeoas­caris spini­col­lis, spend at least part of their com­plex life cycle in the tis­sues of African claw­less ot­ters . There are no known ec­topar­a­sites. (Lar­ivière, 2001)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

African claw­less ot­ters are hunted for their pelts and other body parts, and they are oc­ca­sion­ally kept as pets. (Hoff­mann, 2010)

• Positive Impacts
• pet trade
• body parts are source of valuable material

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Due to their diet, fish­er­men view African claw­less ot­ters as com­peti­tors for fish and fish prey. African claw­less ot­ters are oc­ca­sion­ally viewed as agri­cul­tural pests as they also some­times kill poul­try. (Hoff­mann, 2010)

Con­ser­va­tion Sta­tus

Pop­u­la­tions of African claw­less ot­ters are wide­spread and sta­ble, and the IUCN Red List of Threat­ened Species lists them as "least con­cern". How­ever, hu­man-in­duced habi­tat change is a po­ten­tial threat to some local pop­u­la­tions. African claw­less ot­ters in Nige­ria and Cameroon are listed under CITES Ap­pen­dix I, while all oth­ers are listed under Ap­pen­dix II. (Hoff­mann, 2010)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  Appendix I Appendix II

Con­trib­u­tors

Daniel Kowal­sky (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor, John Berini (ed­i­tor), An­i­mal Di­ver­sity Web Staff.

Ref­er­ences

Hoff­mann, M. 2010. "Aonyx capen­sis" (On-line). IUCN Red List of Threat­ened Species. Ac­cessed April 01, 2011 at http://​www.​iucnredlist.​org/​apps/​redlist/​details/​1793/​0.

Jacques, H., G. Veron, F. Alary, S. Aulagnier. 2009. The Congo Claw­less Otter (Aonyx con­g­i­cus) (Mustel­idae: Lutri­nae): A Re­view of Its Sys­tem­at­ics, Dis­tri­b­u­tion and Con­ser­va­tion Sta­tus. African zo­ol­ogy, 44/2: 159-170. Ac­cessed March 14, 2011 at http://​dx.​doi.​org/​10.​3377/​004.​044.​0204.

Lar­ivière, S. 2001. Aonyx capen­sis. Mam­malian Species: 1-6. Ac­cessed March 10, 2011 at http://​dx.​doi.​org/​10.​1644/​1545-1410(2001)671<0001:AC>2.​0.​CO;2.

Nel, J., M. Somers. 2007. Dis­tri­b­u­tion and habi­tat choice of Cape claw­less ot­ters, in South Africa. South African Jour­nal of Wildlife Re­search, 37/1: 61-70. Ac­cessed March 10, 2011 at http://​dx.​doi.​org/​10.​3957/​0379-4369-37.​1.​61.

Parker, D. 2005. The diet of Cape claw­less ot­ters at two sites along the Bloukrans River, east­ern Cape Province, South Africa. African zo­ol­ogy, 40/2: 330-334.

Per­rin, M., C. Caru­gati. 2000. Food habits of co­ex­ist­ing Cape claw­less otter and spot­ted-necked otter in the KwaZulu-Na­tal Drak­ens­berg, South Africa. South African Jour­nal of Wildlife Re­search, 30/2: 85-92.

Somers, M., J. Nel. 2003. Diet in re­la­tion to prey of Cape claw­less ot­ters in two rivers in the West­ern Cape Province, South Africa. African zo­ol­ogy, 38/2: 317-326.

Somers, M., J. Nel. 2004. Move­ment pat­terns and home range of Cape claw­less ot­ters (Aonyx capen­sis), af­fected by high food den­sity patches. Jour­nal of zo­ol­ogy, 262/1: 91-98. Ac­cessed March 10, 2011 at http://​sfx.​lib.​umich.​edu:​9003/​sfx_​local?​sid=CSA%3Azooclust-set-c&​pid=%3CAN%3EZOOR14005029188%3C%2FAN%3E%26%3CPY%3E2004%3C%2FPY%3E%26%3CAU%3ESomers%2C%20M.​J.​%20%7Ba%7D%3B%20Nel%2C%20J.​A.​J.​%3C%2FAU%3E&​issn=0952-8369&​volume=262&​issue=1&​spage=91&​epage=98&​date=2004-01&​genre=article&​aulast=Somers&​auinit=MJ%7Ba%7D&​title=Journal%20of%20Zoology%20%28London%29&​atitle=Movement%20patterns%20and%20home%20range%20of%20Cape%20clawless%20otters%20%28Aonyx%20capensis%29%2C%20affected%20by%20high%20food%20density%20patches.

Wot­ton, S., T. Mor­ris, G. An­der­son, G. Shorrock. 2010. Threat­ened species sur­veys in the Gola For­est Re­serves, Sierra Leone. Ibis, 152/1: 205-206.