The tri-colored bat (Perimyotis subflavus) used to be known as the eastern pipistrelle. Genetic evidence has shown that this bat is not related to other pipistrelles and it has therefore been renamed for its distinctive tri-colored fur. This is one of the smallest bats in Ohio and can easily be mistaken for a large moth in flight. Banding techniques used to study migration in North American bats were first used on tri-colored bats in the early 1900s.
This small bat varies overall in color from a pale yellowish-brown to dark reddish-brown. The fur has three color bands, with the base being the darkest, the middle being the lightest, and the tip being a medium shade. The forearms are pinkish and the wing membrane is black. The ears are longer than they are wide. The anterior third of the uropatagium (tail membrane) is furred.
Males and females copulate in the fall and fertilization is delayed until the spring when females emerge from hibernation, although some tri-colored bats mate again in the spring. Gestation lasts at least 44 days. Offspring, normally referred to as pups, are born from June to mid-July. Tri-colored bats usually have two pups but can have one to three. Newborns can make loud, audible clicking sounds, which may help their mothers find them. By the third or fourth week after birth, pups can fly on their own.
Habitat & Behavior
Tri-colored bats prefer open forest areas that are near a source of water in the summer. They are among the first bats to emerge in the evening and can been seen foraging at treetop level or higher. Because of their small size, tri-colored bats are limited to small prey such as flies beetles, moths, and true bugs that are 4-10 mm in length. One study recorded a tri-colored bat catching an insect every two seconds!
Tri- colored bats are classified as cave-dwelling bats. In the winter, these bats can be found in caves, mines, and rock crevices. They sometimes roost with other bat species, but generally roost alone or in small groups throughout a hibernaculum. In Ohio, tri-colored bats hibernate from October to April or May. They are relatively inactive during hibernation compared to other species, which leads to condensation collecting on their fur and giving them a jeweled appearance. Caves are included in the Cave Protection Act portion of the Ohio Revised Code 1517. This cave protection act ensures that cave life and material is conserved, which includes bats hibernating within them. In the summer, female tri-colored bats form small maternity colonies and males roost alone. Most maternity roosts appear to be in clusters of dead leaves in trees, although they can also use hollow trees, caves, rock crevices, and buildings.