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
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
Rice farmers complain about Asian clawless otters uprooting plants in the paddies.
Aonyx cinerea consume small crabs which are considered agricultural pests.
Positive Impacts: controls pest population
The role of A. cinereus in the ecosystem is not well understood. They impact the populations of shellfish and crustaceans in their area.
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 )
Aonyx cinerea is found in coastal regions from southern India to the Malay Peninsula and southern China.
Biogeographic Regions: oriental (Native ); indian ocean
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
A captive specimen of A. cinereus lived about 16 years.
Range lifespan
Status: captivity: 16 (high) years.
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
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.
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
