Where people hunt them, they move about more at night than during the day. They hunt mostly alone, but sometimes they hunt in family groups. Otters spend much time playing. They wrestle and romp and slide down steep muddy slopes in summer and down icy riverbanks in winter. Otters use a variety of sounds to communicate among themselves.
All species have a warning growl.
In addition, otters use various kinds of chirps, chuckles, screams, and squeals to express their feelings to other otters. Most otters make their homes in burrows in riverbanks or under rocky ledges, or in abandoned dens of other animals. Most female otters give birth to two or three young at a time. The babies, called cubs or pups, are born blind. The young do not swim until they are several months old.