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Home -> Kingdom Animalia -> Phylum Chordata -> Subphylum Vertebrata -> Class Mammalia -> Order Carnivora -> Suborder Caniformia -> Family Mustelidae -> Subfamily Lutrinae -> Species Aonyx cinerea

Aonyx cinerea
Oriental small-clawed otter



2009/11/22 01:39:57.235 US/Eastern

By David Hamman

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Family: Mustelidae
Subfamily: Lutrinae
Genus: Aonyx
Species: Aonyx cinerea

Geographic Range

Aonyx cinerea is found in coastal regions from southern India to the Malay Peninsula and southern China. (Nowak, 1999; Timmis, 1971)

Biogeographic Regions:
oriental (native ); indian ocean.

Habitat

Aonyx cinerea individuals are commonly seen in the shallows of freshwater streams and rivers as well as coastal regions. There is often dense foliage nearby, which they use as defensive cover, and which restricts behavioral studies in the wild. Nesting burrows are dug into the muddy banks where they live. They have also been seen numerous times in rice paddies. (Hoogerwerf, 1970; Mason and Macdonald, 1986; Timmis, 1971)

These animals are found in the following types of habitat:
tropical ; saltwater or marine ; freshwater .

Aquatic Biomes:
rivers and streams; coastal .

Other:
riparian .

Physical Description

Mass
2.70 to 5.40 kg
(5.94 to 11.88 lbs)


Length
406 to 635 mm
(15.98 to 25 in)


Aonyx cinerea weigh 2.7 to 5.4 kg, have a combined head and body length of 406 to 635 mm, and a tail length of 246 to 304 mm. They have dark, greyish-brown fur over most of their body, and a lighter cream coloration on their face and neck. Their claws are extremely reduced, and rarely extend past the digit. The paws are only partially webbed, which allows for more dexterity than otters with full webbing. (Mason and Macdonald, 1986; Timmis, 1971)

Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .

Reproduction

Breeding interval
Aonyx cinerea may produce two litters annually.

Breeding season
Mating may occur throughout the year.

Number of offspring
2 (average)

Gestation period
60 days (average)

Time to weaning
80 days (average)

Asian clawless otters form monogamous pairs for life. (Lancaster, 1975; Leslie, 1970)

Mating systems:
monogamous .

The estrous cycle is 28 days with a 3 day period of estrus. Mated pairs can have two litters of 1 to 6 young (usually 1 or 2) per year. Gestation is approximately 60 days, and newborn young are relatively undeveloped. At birth, they weigh around 50 g and have closed eyes. Eyes open at around 40 days, and pups can be seen outside the den after ten weeks. Young begin eating solid food after 80 days, and start swimming after three months. (Lancaster, 1975; Leslie, 1970)

Key reproductive features:
iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .

Males assist with nest building before birth and food procurement after parturition. (Lancaster, 1975; Leslie, 1970)

Parental investment:
male parental care ; female parental care .

Lifespan/Longevity

Extreme lifespan (captivity)
16 years (high)

A captive specimen of A. cinerea lived about 16 years. (Nowak, 1999)

Behavior

Aonyx cinerea live in extended family groups of approximately twelve individuals. They are social and vocal animals. They are often seen playing on mud banks and in the water, and slides are quite obvious in regions where they either frequently visit or permanently live. In captivity they are often seen juggling pebbles and other small objects. They are mainly active during the day. (Hoogerwerf, 1970; Medway, 1969; Timmis, 1971)

Key behaviors:
natatorial ; diurnal ; motile ; sedentary ; social .

Communication and Perception

Twelve different vocalizations have been identified in this species, not counting simple alarm vocalizations. Communication also occurs with visual, chemical, and tactile cues such as social grooming, hormonal changes, and posturing. (Timmis, 1971)

Communicates with:
visual ; tactile ; acoustic ; chemical .

Perception channels:
visual ; tactile ; acoustic ; chemical .

Food Habits

Unlike most otters, A. cinerea individuals use their forepaws to locate and capture items, rather than their mouth. Their incomplete webbing gives them a great deal of manual dexterity. They dig in sand and mud at the shoreline for various types of shellfish (clams and mussels) and crabs. To get at the meat they can either crush the shell manually or let heat from the sun open the shells. Their teeth are broad and robust, well-suited for crushing shells. (Timmis, 1971)

Primary Diet:
carnivore (eats non-insect arthropods, molluscivore ).

Animal Foods:
amphibians; fish; terrestrial non-insect arthropods; mollusks.

Predation

Predation on A. cinerea has not been described but it is likely that they are taken by large, primarily aquatic predators, such as crocodiles and snakes. Their amazing agility in the water may help them to avoid predation.

Ecosystem Roles

The role of A. cinerea in the ecosystem is not well understood. They impact the populations of shellfish and crustaceans in their area.

Economic Importance for Humans: Negative

Rice farmers complain about Asian clawless otters uprooting plants in the paddies. (Mason and Macdonald, 1986)

Economic Importance for Humans: Positive

Aonyx cinerea consume small crabs which are considered agricultural pests. (Mason and Macdonald, 1986)

Ways that people benefit from these animals:
controls pest population.

Conservation Status

IUCN Red List: [link]:
Near Threatened.

US Federal List: [link]:
No special status.

CITES: [link]:
No special status.

Clawless otters are managed under the Species Survival Program. While not endangered themselves, they are being used as a model for the management of other otter species. (Lankard, 2001)

Contributors

David Hamman (author), Michigan State University.
Dr. Barbara Lundrigan external link (editor), Michigan State University.

References

Hoogerwerf, A. 1970. Udjung Kulon. Leiden: E. J. Brill.

Lancaster, W. 1975. Exhibiting and breeding the asian small-clawed otter at Adelaide Zoo. International Zoo Yearbook, 15: 63-65.

Lankard, J. 2001. AZA annual report on conservation and science 1999-2000. Volume I: Conservation programs reports. Silver Springs, MD: American Zoo and Aquarium Association..

Leslie, G. 1970. Observations on Oriental short-clawed otter at Aberdeen Zoo. International Zoo Yearbook, 10: 79-81.

Mason, C., S. Macdonald. 1986. Otters: ecology and conservation. Cambridge University Press.

Medway, L. 1969. The wild mammals of Malaya. Kuala Lampur: Oxford University Press.

Nowak, R. 1999. Walker's Mammals of the World, Volume 1. Baltimore and London: The Johns Hopkin University Press.

Timmis, W. 1971. Observations on breeding the Oriental short-clawed otter, *Amblonyx cinerea*, at Chester Zoo. International Zoo Yearbook, 11: 109-111.

2009/11/22 01:39:58.653 US/Eastern

To cite this page: Hamman, D. 2004. "Aonyx cinerea" (On-line), Animal Diversity Web. Accessed November 24, 2009 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Aonyx_cinerea.html.

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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