Aonyx cinerea
Oriental small-clawed otter

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

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)

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)

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

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)

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

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

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)

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)

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)

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.

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. (Mason and Macdonald, 1986)

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

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)