Strong, swift fliers, they take to the air later than most other bats. They prey mostly on moths, but also take beetles and mosquitoes. Hoary bats migrate to warmer climates in winter. In spring, they return and raise young. The young are born from mid-May to early July, usually two to a litter.
Females have two pairs of breasts and sometimes have three of four pups in a litter.
The female gives birth while hanging in a tree. Young grow rapidly and are able to shift for themselves in about a month.