Spotted-necked otters feed primarily on fish but also eat frogs and small crustaceans, especially when fish are in short supply. The otters are sometimes found in family groups, but appear to be social only under certain conditions. Males and females are separated for at least part of the year. They normally hunt alone, except when mothers are training their young, and are not territorial, sheltering through the night in short burrows, rock crevices, or patches of dense vegetation. On land, they travel mainly by the use of regular paths, and rarely move more than 10 m from river or lake banks. As with many other otters, these paths are marked by “sprainting” sites in which they habitually defecate and urinate.