Asian Short Clawed Otter

Maximum longevity: 23 years (captivity) Observations: One wild born female was about 23 years old when she died in captivity (Richard Weigl 2005).

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.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: vulnerable

Predation on A. cinereus 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.

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.

Range mass: 2.7 to 5.4 kg.

Range length: 406 to 635 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

A captive specimen of A. cinereus lived about 16 years.

Range lifespan
Status: captivity: 16 (high) years.

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.

Habitat Regions: tropical ; saltwater or marine ; freshwater

Aquatic Biomes: rivers and streams; coastal

Other Habitat Features: riparian

Aonyx cinerea is found in coastal regions from southern India to the Malay Peninsula and southern China.

Biogeographic Regions: oriental (Native ); indian ocean

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.

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

Primary Diet: carnivore (Eats non-insect arthropods, Molluscivore )

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

Aonyx cinerea consume small crabs which are considered agricultural pests.

Positive Impacts: controls pest population

Rice farmers complain about Asian clawless otters uprooting plants in the paddies.

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.

Communication Channels: visual ; tactile ; acoustic ; chemical

Perception Channels: visual ; tactile ; acoustic ; chemical

Asian clawless otters form monogamous pairs for life.

Mating System: 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.

Breeding interval: Aonyx cinerea may produce two litters annually.

Breeding season: Mating may occur throughout the year.

Average number of offspring: 2.

Average gestation period: 60 days.

Average weaning age: 80 days.

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.

Parental Investment: male parental care ; female parental care

The Asian short-clawed otter is a sociable animal, living in loose family groups of about 12 individuals (2). Within each group is an adult monogamous pair, with both parents contributing to the raising of their offspring (5). The female gives birth to up to two litters each year (2), each containing up to six young but often just containing one or two. The young are born after a gestation period of 60 to 64 days (2), into a nest of grass that the female has built two weeks prior (5). The young otters do not open their eyes until 40 days old. At nine weeks of age they take their first swim and, shortly after, they eat solid food (2). The diet of the Asian short-clawed otter consists primarily of crabs, other crustaceans, molluscs, frogs (2), fish, snakes and insects (6). With their sensitive and dexterous front paws, they dig around in the mud or under stones to find their prey (2). With their large back teeth, the Asian short-clawed otter can crush the shells of crabs and molluscs, or they have been known to leave these creatures out in the sun once they have been dug up, where the heat causes the shells to open up (5). In areas of rice fields, the Asian short-clawed otter may serve a valuable function to farmers as it preys on the crabs found in the paddies (6). When not searching for food, this playful otter may be found along the grassy or sandy banks of rivers, resting or grooming (5). It interacts with other members of the family group using a vocabulary of at least 12 calls (2), including greeting, mating and alarm calls (5). In Malaysia at night, their chirps are often heard as they move through rice fields (6).

Limited conservation measures are in place for the Asian short-clawed otter. There is some national legal protection in place for this species (4), for example, in Malaysia and Singapore, all otters are totally protected (8), but local habitat protection needs to be established (4). In 1983, the American Association of Zoological Parks and Aquariums established a species survival plan to encourage more research on the captive breeding of this species (5). Many zoos in the world keep this species (8), creating the opportunity for scientists to gain further knowledge about this fascinating mammal, which can then be used to assist their conservation in the wild. One of the key organisations involved in the conservation of the Asian short-clawed otter is the IUCN Otter Specialist Group, which has developed a network of biologists across Asia that are conducting field surveys and popularising this species' conservation. Nevertheless, concerted conservation effort—involving policy, research and habitat-based action—is required if the long-term survival of the Asian short-clawed otter is to be assured (1).

This charismatic mammal, equally at home in the water and on land, is the smallest of the world's otters (4). As well as its size, the Asian short-clawed otter can be distinguished from other otters by its small claws (5), after which it is named. These tiny claws, which do not protrude beyond the ends of the fingers (2), enhance the manual dexterity of this otter as it handles prey (5). The Asian short-clawed otter typically has brown fur with a paler underside, although cream-coloured individuals have also been known (5) (6). The edges of the upper lip, chin, throat, sides of neck and face are generally greyish-white (5). Like other otters, the Asian short-clawed otter has a small head, short legs and flattened tail, creating a streamlined silhouette that can move easily through the water (5) (7).

A truly amphibious animal, the Asian short-clawed otter can be found in, and around, rivers, creeks, estuaries, coastal waters (2), mangroves and rice fields (6), often close to human activity (5). It prefers areas of shallow water, where there is both abundant food and sufficient vegetation (4), and can be found from sea level up to 2,000 metres (5).

The Asian short-clawed otter has a large distribution, ranging from north-western and southern India, through southern China and the Malay Peninsula, to Sumatra, Java, Borneo and the Riau Archipelago (Indonesia), and Palawan Island in the Philippines (2).

Classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

The most significant threat to the Asian short-clawed otter is the destruction of habitat (1). Throughout Asia, deforestation is resulting in the loss of hill streams, peat swamp forests are drained for agriculture, and mangroves are being converted for aquaculture (1) (4). Aquaculture projects are a particular problem, as they bring otters in closer contact with humans who view them as pests. Few areas can afford the fences needed to keep otters from killing the fish or prawn stocks; instead, the otters are killed (6). Further threats to this species include a reduction in their prey as a result of overexploitation by humans, and pollution, which may also affect prey abundance, as well as the otter directly (1) (4). Tea and coffee plantations in India, and other forms of intensive agriculture elsewhere, not only often destroy the otter's natural habitat, but result in the surrounding streams and rivers being polluted by pesticides (1) (4).

Provides brief summary of Asian small-clawed otter