Bats of Kentucky

Rafinesque's Big-Eared BatBats are the only true flying mammals. They belong to the mammalian order Chiroptera meaning ‘hand wing’ which references the elongated finger bones that make up a bat’s wing (see line drawing below.) All of Kentucky’s bat species are insectivores, meaning they all primarily eat insects. They respond to the lack of insect availability in the winter by hibernating (or heading south to warmer regions.) Bats that hibernate in Kentucky will mate in the fall and winter. Female bats store sperm over the winter and ovulation and fertization do not occur until the females arouse from hibernation. Females usually emerge from hibernation before males. In many species, they establish maternity colonies where they will have their young. A few species like the gray bat will gather in caves, others like the Indiana bat form colonies under loose tree bark, and still others may gather in manmade structures like the big brown bat. Additionally, some species such as the red bat will remain solitary. Each female may bear between one to four young called ‘pups’, generally from late May through June.

Sixteen species of bats have been documented in Kentucky (see list below.) Fourteen of these species are considered permanent or seasonal residents. The Seminole bat appears to be expanding its range into Kentucky and possibly breeds here now. The Brazilian (or Mexican) free-tailed bat occurs as an occasional wanderer, though there is prehistoric evidence that the species used to reside in Kentucky. Three of Kentucky’s bat species are federally endangered, the Virginia big eared bat (Corynorhinus townsendii virginianus), the Indiana bat (Myotis sodalis), and the gray bat (Myotis grisescens). The Northern long-eared bat (Myotis septentrionalis) is listed as federally threatened.

To learn more, click on any of the species links below. Photos and Kentucky distribution maps are provided for each species. Line drawings showing basic anatomy of a bat are also included below. They help highlight the key features used to identify certain species. Keep in mind that distinguishing among some of the Myotis species is hard even for a trained biologist!

Note:  A calcar is the cartilaginous spur that extends from the ankle. A keeled calcar refers to a calcar with a small flap of skin extending beyond it. The presence or absence of this characteristic helps biologists to identify some bats. Another thing biologists look at is the tragus, which is shaped differently among species. The tragus is a fleshy projection in front of the ear canal that helps a bat with sound localization. Bat biologists even look at the length and density of bat toe hairs to aid with identification. Talk about attention to detail!! Luckily, some bats can be identified without looking at any of these characters.

Bat illustration by Rick Hill
Illustration by Rick Hill, KDFWR after Schwartz