Heavily influenced by photoperiod. May come into heat at any time of the year, especially if kept in artificial light as in a home, but usually do not come into heat from mid-fall to mid-winter(oct-jan), when the days are the shortest. Estrus lasts 8-10 days. Are induced ovulators. If they do not mate, they will not ovulate and will come into estrus again in 2-14 days. If they mate, ovulate, but are not pregnant, they will come into estrus in about 45 days. Free roaming intact females have 2-4 litters a year.