Eastern red bat
|Eastern red bat|
|Eastern red bat|
The eastern red bat (Lasiurus borealis) is a species of bat in the family Vespertilionidae. Eastern red bats are widespread across eastern North America, with additional records in Bermuda. They are also present, though rare, throughout many of the Bahamian islands. The eastern red bat is closely related to the desert red bat (Lasiurus blossevillii); the two species are sometimes collectively referred to simply as red bats.
This is a medium-sized Vespertilionid, averaging weights of 9.5–14 g and measurements of 112.3 millimetres (4.42 in) in total length. Adults are usually dimorphic: males have red hair, while females are chestnut-colored with whitish frosting on the tips of the fur.
Like most vespertilionids, eastern red bats are insectivorous. Moths (Lepidoptera) form the majority of the diet, but red bats also prey heavily on beetles (Coleoptera), flies (Diptera), and other insects. Echolocation calls have low minimum frequencies, but calls are highly variable, ranging from 35–50 kHz. Eastern red bats are best suited for foraging in open spaces due to their body size, wing shape, and echolocation call structure. Even so, they are frequently captured by researchers foraging over narrow streams and roads.
Mating likely occurs in late summer or autumn and the sperm is stored in the female's reproductive tract until spring when ovulation and fertilization occurs. In June, females usually give birth to three or four young and then roost with their young until they are weaned. Males roost alone throughout the summer. High temperature demands associated with gestation and rearing young may limit the northern range for reproductive females. Eastern red bats often roost among live or dead leaves on the branches of live hardwood trees, but have also been found using loblolly pine trees in pine plantations.
In late summer, eastern red bats from the northern parts of the range may migrate south for the winter, although little is known about their migration routes or overwintering range. In winter, red bats forage for insects on warm nights and even warm days. On warm days during the winter, red bats enter torpor while roosting in the canopy of hardwood or coniferous trees, but during cold bouts they crawl underneath dead leaf litter on the ground and use their furred tail as a blanket.
- Ford, W. Mark; Michael A. Menzel; Jennifer M. Menzel; and Dorothy J. (Jan. 2002). Welch Influence of Summer Temperature on Sex Ratios in Eastern Red Bats. American Midland Naturalist' 147(1):179-184.
- Buden, DW. (1986). Distribution of Mammals of the Bahamas. Florida Field Naturalist' 14(3): 53-84.
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