Because time of parturition is likely determined by local climate, the gestation period is variable, but averages about nine weeks. In the southwestern United States mating takes place from October to December. Pallid Bats, like most bats, have low reproductive rates and produce one litter annually. Male and female Pallid Bats become sexually active in their second year of life. Because the Okanagan Valley is the northern extent of the Pallid Bat's range, the habitat is probably at the limit of this species' tolerance resulting in litters of only one or two young, with twins most common.
Females are capable of breeding in their first year but yearling females can bear only one young.
In four or five weeks they are capable of short flights and by eight weeks they attain adult size. In summer this species is a late feeder leaving its day roost about 45 minutes after sunset. Pallid Bats may commute up to four kilometres between their day roosts and foraging areas. In British Columbia, this species seems to hunt mainly over tracts of open grassland sparsely covered with Big Sagebrush, Rabbit Brush and Bitter-brush. Gravel roads may provide foraging corridors - there are several observations of Pallid Bat flying low over roads in the Okanagan.