Because of an extra thick coat of fur they are born with, they spend their time floating like little furry wine bottle corks in the water or resting on their mothers' belly, where they are protected and learn to clean themselves and eat. River otter pups are born toothless and blind in a den on land. They open their eyes at about seven weeks and leave the den after about two months. They begin to eat solid food at that time and are taught to swim by their mother, who must coax or drag them out of the den. They stay with their mothers until shortly before the next litter is born.
Mothers produce litters about once a year.
Litters in size from one to six pups but average between two and four pups.