This is the largest otter (Lutrogale perspicillata) in Asia, and like all otters it has a long, thick body, short legs, and webbed feet with sharp claws. The neck is as wide as the body and head. The ears are set low on the domed head, but the small, round eyes are set high up and wide apart. The muzzle is short and covered in thick whiskers. The fur is thick and velvety with two layers; the guard fur keeps the underfur dry underwater to retain body heat. To help with swimming, the smooth-coated otter’s front legs are shorter than the back legs and it has a thick, conical tail that is more flattened than other otters, particularly at the end. Males are larger than females.