Smooth-coated otters are the largest of Asia’s otters and have a very smooth, sleek pelage. Their fur is velvety and thick and has two layers: their guard fur keeps their underfur dry under water to keep their body heat. This animal’s front legs are shorter than its rear legs, which helps with swimming, and its thick, conical tail is more flattened than in other otters, especially at the end. The males are larger than the females.
The Smooth-coated otter lives in southern and Southeast Asia, China, and India, and in Iraq there is a small population. These otters are primarily found in lowlands, peat swamp forests, coastal mangrove forests, large forested rivers, freshwater wetlands, lakes, and rice paddies. Smooth-coated otters are adapted to water but are equally comfortable being on land and are able to travel long distances overland when seeking a suitable habitat. These animals in Malaysia are more abundant in the mangrove forests than in the river systems.
This species is unusually social and mostly nocturnal. Family groups which include the breeding pair with up to four young born in previous seasons may nest and hunt together within a territory measuring 7 – 12 km². They mark their territory with a strong musky scent that they spread on vegetation from the anal scent glands of both males and females, a behavior called sprainting. The male is larger but the female is the dominant one in the group. These animals are active, hunting in groups both during the night and the day. When they fish, they travel upstream in a V-formation. Most of their foraging activity is in water. Small fish they swallow whole, but they take large fish to shore. Nights are spent in dens that they dig in dense vegetation, among boulders or under tree roots. They communicate through the use of scent, within the otter species, as well as with other animals. Other means of communication they use are vocalizations such as whistles, wails and chirps.
These otters form strong monogamous bonds. Breeding is from August to December. Gestation lasts 60-62 days, and one to five young are born and raised in a shelter or burrow near water, which the otters excavate, or they take over an abandoned one. The pups are blind and helpless when born, their eyes opening at four weeks. At six weeks they start learning to swim. The young are weaned after five months. The father is permitted to join the group once the pups are weaned, whereupon he helps provide food for them. At one year old, young often disperse to find a home range of their own. This species attains reproductive maturity when they are 22 months old.
Despite a diverse habitat preference, a major threat to this species’ survival is the loss of habitat suitable for them. Large-scale hydroelectric projects and land clearance for agriculture and settlement have had a major impact on this otter, as has habitat degradation due to water pollution from fertilizers and pesticides. Poaching occurs, primarily in India, Bangladesh and Nepal.
There are no estimates of population numbers for Smooth-coated otter. Currently this species is classified as Vulnerable (VU) on the IUCN Red List and its numbers today are decreasing.
This species affects aquatic vertebrate and invertebrate populations via predation.