River Otters

River otters in Alaska breed in spring, usually in May. Mating can take place in or out of the water. One to six pups (usually two or three) are born the next year any time from late January to June following a gestation period of nine to 13 months. Delayed implantation (a period of arrested embryonic growth) accounts for this variation in the length of gestation.
The pups are born toothless and blind in a den that is usually a subterranean burrow. Their eyes open seven weeks later. When about two months old, they begin to leave the den and shortly thereafter start to swim and eat solid food. They are taught to swim by the female who must coax or drag them into the water. Pups are weaned when about five months old. They will stay with their mother until shortly before her next litter is born.
River otters are sexually mature when they are two years old. A female will then mate with the male of her choice and produce one litter each year. Otters can live and breed for more than 20 years.