Reproduction and life cycle The tricolored bat is a
seasonal breeder, with
copulation (mating) occurring in the fall before hibernation.
Ovulation does not occur until the spring, however, and females store the males'
sperm in their
uteruses through the winter.
Gestation (pregnancy) length is about forty-four days, with females giving birth in June or July. The litter size is typically two individuals. As newborns, the combined mass of twin pups can be as great as 58% of the mother's postpartum mass. At birth, the young lack fur and their eyes are closed. Males are solitary and do not form colonies. In the winter, the tricolored bat
hibernates in mines, caves, or other human structures. A years-long study of a mine in the US state of Nebraska found that in the summer, the mine was mostly occupied by males. Total number of tricolored bats using the mine at one time ranged from zero to forty-three. Bats were in a state of
torpor from November to April. More bats used the mine as a roost in the winter than in the summer. In another abandoned mine in the US state of Indiana, researchers found that the tricolored bat roosts solitarily during hibernation for the majority of the time (96.8% of observations were singletons). During hibernation, males lose an average of , while females lose an average of .
Diet and foraging The tricolored bat is
insectivorous, consuming small prey of in length. Prey taxa include
mosquitoes,
beetles,
ants,
moths, and
cicadas. It forages with slow, erratic flight in areas near water or forest edges. The tricolored bat is the host to several species of endoparasites (internal parasites) and ectoparasites. Oocysts (spores) of an
Eimeria species (
Eimeria heidti ) have been recovered from its
guano (feces). The tricolored bat has experienced severe population decline as a result of the fungal disease
white-nose syndrome, which arrived in the US in 2006, with losses of 70% and greater detected in multiple US states. The disease kills bats by colonizing their skin during the winter, causing them to arouse from torpor and burn through their limited fat reserves. Though its population experienced dramatic reduction, subsequent studies have found that their numbers may be stabilizing, though hibernacula where many individuals once roosted may only host fewer than five bats, or even one solitarily. ==Range and habitat==