An adult chipmunk is 8 1/2 to 11 1/2 inches in length. Its tail is approximately 4 inches in length. The widest part of the body is around the shoulder area, about 1 1/2 inches across. The adult chipmunk weighs approximately 2 1/2 to 5 ounces. There is very little difference between the male, and female, in both colors or weight.
Mating occurs in early Spring, and there is one litter per year. An average of 3 to 5 young are born in May, there have been reported litters as large as ten. The Chipmunk is a social animal, in that both the male and female raise the young.