Breeding takes place in early spring. Female woodchucks are monoestrus, mating soon after they emerge from hibernation in April. Females bear a single litter of one to nine (the average litter size contains three to five young) after a gestation period of 31 or 32 days. The young are born in May and at birth are naked, pink, wrinkled, and blind and helpless. Young weigh 26 to 27g and measure about 4 1/4 in. in length. At one week, their skin becomes pigmented. Black body hair emerges during the second week. At three weeks, the young are capable of crawling and by the fourth week, they can open their eyes. At five weeks, the young woodchucks are fully active. The female parent is reported to stand while she nurses her litter. She has four pairs of teats. Woodchuck offspring (both male and female) are weaned after a month and a half and are usually forced to disperse in their first summer of life, when they are about six weeks old. Offspring usually do not become sexually mature until their second spring.
