The Japanese noctule is an insectivorous species (4). Although little is known of the specific diet of the Japanese noctule, it is likely to be similar to that of closely related bats. Noctule bats (Nyctalus species) are typically fond of beetles, catching them midflight (4) (7), but they may also eat moths, winged ants and other insects (4). Noctule bats typically hunt for prey during flights just before sunrise and in the early evening (4).
Bats in the Vespertilionidae family typically mate in the autumn, prior to hibernation. The sperm remains viable in the oviduct of the female, until the female is aroused from hibernation in early spring, when the female ovulates and fertilisation then occurs (8).
Pregnant females often roost together in large colonies of up to 400 individuals, while the males roost separately (4). Each female bat gives birth between 1 and 3 young in the spring (4), after a gestation period of 70 to 75 days (4). Bats in the Vespertilionidae family can live for up to 30 years (9).