North American river otters are known for their boundless energy, and they must eat frequently. They catch fish in their mouths and detect other prey by feeling with their whiskers along the bottoms of streams. Unlike many other otters which chew their food, the river otter's prey is gulped down immediately.
Mating takes place in March and April. The young are born almost a year later. The females give birth in dens close to the water's edge. They drive the males away soon after the birth of their young, but the dog otters return later to help raise the offspring. The young depart at the age of one year.