Bats of Colorado > Red bat (Lasiurus borealis)
As the name indicates, this is a colorful bat, varying from bright reddish orange to yellow. It is a medium-sized bat with long (300 mm) pointed wings and a distinctly long tail and uropatagium. Average measurements of 11 females from Kansas were: total length, 114 mm; forearm, 53 mm.
Mostly a species of the eastern United States, the red bat also occurs in the southwestern U.S. and Mexico. In Colorado, it apparently is rare, and mostly is found in riparian woodlands (and artificial extensions such as urban landscaping) along the South Platte and Arkansas rivers and major tributaries.
The red bat is solitary and roosts by day in deciduous trees, such as cottonwoods or fruit trees. It seems to prefer American elms where it hangs among the leaves. Red bats usually are well hidden and only can be seen from directly below. They usually roost 4-10 feet off the ground unless they have young, in which case they will be found up to 20 feet high in the tree. Red bats are highly migratory and migrate in groups. Males and females apparently migrate separately, however. Hibernation occurs in the southern states (not in Colorado) where these bats may arouse and forage throughout the winter. Predators include opossums, domestic cats, hawks and owls.
Breeding occurs in the fall. Sperm cells are stored by the female until spring when ovulation and fertilization occur. Gestation takes 80 to 90 days. The red bat typically gives birth to twins (although four young are known) in the early summer. The young are carried by the female from one roost to another and occasionally on feeding flights. Offspring are cared for until they are nearly fully grown. Some reports indicate that the mother carries the young until their weight equals her own. Young red bats are weaned in 4 to 6 weeks and can fly at 3 to 6 weeks of age.
More than other bats, red bats seem to take advantage of insects attracted to lights, and they often are found feeding near street lamps where they appear to be territorial. They alight and feed on non-flying insects, including grasshoppers and crickets. They feed near moth-infested areas, which is certainly a benefit to humans. Foraging occurs in early evening when they leave their roosts and fly in high, lazy patterns over the trees and along forest edges. When it is dark, they descend and feed below the treetops to within a few feet of the ground.
The unusual hibernating behavior of this species is of special interest to science. Red bats survive at subfreezing temperatures and are able to arouse readily from deep sleep.
Neubaum, D. J. 2005. Records of the eastern red bat on the northern Front Range of Colorado. Prairie Naturalist 37:41-42.
