Males keep harems of one to three females.
Harems appearently begin to form in groups of immigrating subadults during the year before breeding. In the laboratory, females may have up to seven litters in 1 year, but under favorable conditions in the wild, two litters may be produced during the same year about 2 months apart. In the northern part of their range, probably only one litter is produced each year. Maturation time seems to vary from one area to another. Dispersal - Dispersal of young may occur shortly after weaning or over several years.