The fur is long, silky, and varies in color from Chocolate-brown to reddish- or golden-brown. The ears and wing membranes are dark brown to nearly black. The big brown bat is similar in appearance to the evening bat but is larger in size.
Florida roosting preferences: Colonial. Dead tree cavities provide the normal roosting habitat for this bat, but one colony was found roosting in the base of a royal palm leaf stem in south Florida. They also move into buildings, bridges, and bat houses.