How do bats choose optimal temperatures for hibernation?

Abstract

1. 1. Ambient temperatures of hibernating Myotis myotis, Myotis nattereri, Myotis mystacinus/brandti, Plecotus auritus, Pipistrellus pipistrellus lies between −2.5 and 9.0°C. 2. 2. Mean ambient temperature is 5.5°C in Myotis myotis, 4.9°C in Myotis nattereri, 4.6°C in Myotis mystacinus/brandti, 3. 4.0°C in Plecotus auritus. Only in Pipistrellus pipistrellus is mean ambient temperature much lower (1.5°C). 4. 3. Bats prefer hibernacula with a cooler climate; typically it is a cave with the entrance at the highest point of vertical extension. In these caves bats reach ambient temperatures below mean annual temperature. 5. 4. Hibernation temperature also depends on the vertical distribution of the hibernacula. Bats prefer hibernacula at a high height above sea level. There the preferred hibernation temperatures are equal to the mean annual temperature.