Lasiurus borealis , or red bats,are widely distributed in forested regions, occurring from southern Canada through Central America and into Chile and Argentia. The hindfoot length is 6 to 11 mm. Height of the ear from the notch is 8 to 13 mm. Length of the forearm varies between 36 and 46 mm.
Pelage varies in color from a brick red to a yellowish red.
The fur is white at the tips giving this bat a frosted appearance. In general, female bats appear more frosted compared to males, and males have a redder color than females. There is no documented sexual dimorphism in size. The uropatagium is thickly furred on the dorsal side and helps to keep the bat warm in cold weather. Lasiurus borealis have a small and heavily constructed skull.