The Spotted-necked otter is so-called because of the creamy white mottled blotches on the neck and chest. Its long sinuous body is covered in dense, water-repellent fur, and its color ranges from reddish to chocolate brown. More aquatic than other otters from Africa, its fully webbed paws have sharp, well-developed claws. Inside its short, broad muzzle are relatively small teeth, which are adapted for catching fish instead of the crustaceans that the clawless otters eat. Its long hairy tail ends in a point and is flattened horizontally.
The Spotted-necked otter lives throughout sub-Sahara countries from Guinea Bissau to south-west Ethiopia and in the south eastern South Africa. Although it inhabits most countries within this area, it is not found in some large areas of southern Africa. They are aquatic animals and require continuous and permanent waterways, preferring clear water with rocks, and are found in lakes, rivers, swamps, and in mountain streams. They do not occur in shallow alkaline lakes or turbid rivers. They live in dens near a source of water.
Typically solitary, the Spotted-necked otter lives in a small family group, according to the time of year. Sometimes they forage in loosely knit groups with up to 20 individuals. They may do this because it is easier to catch fish if they keep the shoal together. Males have a large home range with more than one female living within it. It has one or more dens (or holts) in its territory, one of the entrances typically being underwater. Although this species is usually crepuscular or nocturnal, the otters in Lake Victoria are diurnal. These animals may be vocal, with a range of calls including a contact call, which is a harsh mewing, and a high pitched distress call which is a squawking. They enjoy playing, either with other otters or alone.
Little is known about the mating system of Spotted-necked otters. However, due to their solitary life it is suggested that they are either polygynous (one male mates with multiple females) or polygynandrous (promiscuous) (both males and females have multiple mates). They may breed seasonally, with the season varies depending on geographic location. Gestation is for two months and pups are born in September, usually two or three of them. They are blind and helpless at birth. Males and females typically only come together for mating purposes, but it has been observed that the male will return after 5 months to help feed the pups. The young begin to swim when they are 8 weeks old and they are weaned when they are 12-16 weeks old. Pups remain with their mother until a year old, this sometimes being after the next litter has been born. Females do not give birth until they are two years old.
Throughout its range this species is declining, due to a range of human activities, in particular pollution and the general degradation of habitats that have fresh water, as a result of agriculture. In some parts of its range this animal is also persecuted as a source of food and fur or because it is seen as a competitor for fish. In large bodies of water such as Lake Victoria, exotic fish may compete for the smaller indigenous fish which these otters eat.
The Spotted-necked otter has a large distribution but no overall population estimate is available. Currently this species is classified as Near Threatened (NT) on the IUCN Red List and its numbers today are decreasing.