in a mine The mating season for the Townsend's big-eared bat takes place in late fall. As with many other bat species, the female stores sperm in her reproductive tract after mating, and fertilization occurs in the spring. Gestation lasts from 50 to 60 days. As with other bat species, pups are born without the ability to fly. Only one pup is birthed per female. One study found the average lifespan of a Townsend's big-eared bat to be 16 years. This bat requires large cavities for roosting; these may include abandoned buildings and mines, caves, and basal cavities of trees. During the summer, males and females occupy separate roosting sites; males are typically solitary, while females form
maternity colonies, where they raise their pups. A maternity colony may range in size from 12 bats to 200, although in the eastern United States, colonies of 1,000 or more have been formed. During tests on straight-line courses,
C. townsendii flew at speeds ranging from 2.9 to 5.5 m/s (6.4 to 12.3 mph). ==Diet and echolocation==