The spotted-necked otter is a relatively small species, with males measuring 71 to 76 cm (28 to 30 in) from nose to rump, and weighing 5.7 to 6.5 kg (13 to 14 lb), while females are 57 to 61 cm (22 to 24 in) and 3.0 to 4.7 kg (6.6 to 10.4 lb).
The tail is long and muscular, measuring 39 to 44 cm (15 to 17 in) in both sexes.
Like many other otters, it is sleek and has webbed paws for swimming.
Females have two pairs of teats, and while males have a large scrotum, the penis is hidden beneath the skin, to reduce drag while swimming.

Although considerable variation exists among individuals, their fur is usually reddish to chocolate brown and marked with creamy or white blotches over the chest and throat.
The head is broad with a short muzzle, small rounded ears, and a hairless nose pad.
The teeth are adapted for consuming fish, with large sharp upper canine teeth, curved lower canines, and sharp carnassial teeth.
The jaws are similarly adapted, with the mandibular fossa fitting so snugly into the condyle on the lower jaw that the latter cannot move sideways, making it easier to capture and hold fish.

Although up to five subspecies have previously been identified, these most likely represent a natural variation in appearance between individuals, and no subspecies are currently recognised.
The spotted-necked otter is a relatively small species, with males measuring 71 to 76 cm (28 to 30 in) from nose to rump, and weighing 5.7 to 6.5 kg (13 to 14 lb), while females are 57 to 61 cm (22 to 24 in) and 3.0 to 4.7 kg (6.6 to 10.4 lb). The tail is long and muscular, measuring 39 to 44 cm (15 to 17 in) in both sexes. Like many other otters, it is sleek and has webbed paws for swimming. Females have two pairs of teats, and while males have a large scrotum, the penis is hidden beneath the skin, to reduce drag while swimming.
Although considerable variation exists among individuals, their fur is usually reddish to chocolate brown and marked with creamy or white blotches over the chest and throat. The head is broad with a short muzzle, small rounded ears, and a hairless nose pad. The teeth are adapted for consuming fish, with large sharp upper canine teeth, curved lower canines, and sharp carnassial teeth. The jaws are similarly adapted, with the mandibular fossa fitting so snugly into the condyle on the lower jaw that the latter cannot move sideways, making it easier to capture and hold fish.
Although up to five subspecies have previously been identified, these most likely represent a natural variation in appearance between individuals, and no subspecies are currently recognised.
Spotted-necked otter