Eastern Pipistrelle - Life History

Life History

Tricolored bats mate in autumn in the area around their hibernacula. The females store their mates' sperm inside their reproductive tracts during their hibernation in winter and ovulate in early spring. They hibernate alone or in small groups in caves or mines at temperatures from 4 to 10°C, and they usually return to the same hibernation site year after year. When they wake up from hibernation, the females form maternity colonies that are no bigger than 20 bats, whereas the males roost alone during summer. These maternity colonies roost in foliage and are usually exposed to more light than any other bat species. After a gestation period of 44 to 60 days, one to two pups are born in June. (Most other species of bats give birth to only one offspring.) Each one weighs about 20% of its mother's weight. For the first few days after birth the mother carries the blind and hairless pups between roosts. They grow quickly, are able to fly within 14–21 days and stop getting nursed at four weeks of age.

Male tricolored bats live for about 15 years; the females can get as old as 10 years.