Stoats live alone and are territorial. The gestation period is usually around 300 days. After mating in the summer, the kits will not be born until the following spring. Female stoats spend almost all their lives either pregnant or in heat.They mate once a year and have several babies, which are called kits. The kits may not develop for 8–9 months after the female becomes pregnant. When weather conditions are good and there is plenty of food, the kits begin to grow and are born within a month. The males do not help raise the babies.