There are three species of clawless otter in the genus Aonyx—two are found in Africa and one in Asia. Otters in this genus differ from river otters and the giant otter in having much smaller claws and in having webbing on their feet that is either absent or does not extend to the ends of their toes. The Asian small-clawed otter (Aonyx cinerea) is the world's smallest otter, measuring just 26-36 in (65-90 cm) and weighing about 11 lb (5 kg). This species lives in small streams, rice paddies, and coastal mangrove swamps from the Philippines through Indonesia, southeast Asia, and southern China westward to southern India. It is a social animal, and lives in groups of up to 15 individuals. Its diet consists primarily of fish, molluscs, and crabs.
Two other species of clawless otter are found in Africa. These are the Cape clawless otter (Aonyx capensis) and the Congo clawless otter (A. congica). The Cape clawless otter of sub-Saharan Africa lives in swamps, rivers, streams, estuaries, and lakes. This species has no webbing on its forefeet, enabling it to use its fingers freely to probe mud and gravel for prey. Its diet includes crabs, molluscs, frogs, and fish. The head and body of the Cape clawless otter measures 28-36 in (72-91 cm) and its tail is 16-28 in (40-71 cm) long. The male is larger than the female.
The Congo clawless otter, found in west and central equatorial Africa, is not as well known as the closely related Cape clawless otter. It is similar in size and color, but is distinguished by silver tips on the fur of the head and neck, and by dark patches of fur between the eyes and nostrils. Of all the otters, this species is least adapted to an aquatic environment. It prefers swampy habitats such as marshes and lake margins, where it preys upon frogs, crabs, earthworms, and fish. The Congo clawless otter has shorter, thinner (less insulating) fur than other otters. Its forefeet are unwebbed, hairless, and clawless—all adaptations for searching for its food in mud, gravel, or other debris.