In Manitoba radio-collared mink were most active at night, with intermediate levels of activity at dawn and dusk. Hydroperiod determines prey abundance and availability in southern Florida, which appear to determine breeding season.
Neonates are altricial and have sparse, light-colored hairs.
The first teeth emerge at 2 to 3 weeks, eyes open at about 3 weeks, and solid food is first taken at about the same time. By 35 days the young are fully homeothermic. By 7 weeks they have achieved 40 percent of their adult body weight and 60 percent of adult body length. A typical litter consists of 3 or 4 kits and ranges from 2 to 10. Neonates have higher survival rates in warm than in cold weather.