Temperatures and Locations Used by Hibernating Bats, Including Myotis sodalis (Indiana Bat), in a Limestone Mine: Implications for Conservation and Management

Understanding temperatures used by hibernating bats will aid conservation and management efforts for many species. A limestone mine with 71 km of passages, used as a hibernaculum by approximately 30,000 bats, was visited four times during a 6-year period. The mine had been surveyed and mapped; therefore, bats could be precisely located and temperatures ( T s ) of the entire hibernaculum ceiling accurately mapped. It was predicted that bats should hibernate between 5 and 10°C to (1) use temperatures that allow a near minimal metabolic rate, (2) maximize the duration of hibernation bouts, (3) avoid more frequent and prolonged arousal at higher temperatures, (4) avoid cold and freezing temperatures that require an increase in metabolism and a decrease in duration of hibernation bouts or that could cause death, and (5) balance benefits of a reduced metabolic rate and costs of metabolic depression. The distribution of each species was not random for location ( P < 0.000) or T s ( P < 0.000). Myotis sodalis (Indiana bat) was most restricted in areas occupied, hibernating in thermally stable yet cold areas ( X̅ = 8.4 ± 1.7°C); 99