Posted in Vespertilionidae


Eastern Red Bat

Lasiurus borealis
Chuck Fergus

The eastern red bat has a bright rusty coat and long, pointed wings that easily distinguish this species. Length is 3.7 - 4.8 inches; wingspread, 11.3 -12.9 inches; and weight, 0.28 - 0.49 ounces. Individuals roost singly in trees (except for females with young), often on forest edges, in hedgerows, and shrubby borders; they seem to prefer American elms. Rarely do they use caves or buildings.  

Red bats start flying early in the evening, preying on moths, flies, bugs, beetles, crickets and cicadas, which they take from air, foliage and ground. Strong fliers, red bats are considered migratory, although little is known about their patterns. The sexes may migrate separately. Red bats start south in September or October, flying at night. They can withstand body temperatures as low as 23 F.  

Females bear 1 - 5 young (usually 2-3) in their treetop roosts. For the first few days, the young remain clinging to their mother when she flies out on hunts. Young are able to fly at 3 - 4 weeks, and are weaned when 5 - 6 weeks old. Longevity is about 12 years. The red bat ranges across Pennsylvania.