Remarks on the thermopreferendum of palearctic bats in their natural habitats

This contribution comprises two remarks of ecological rather than physiological character. Contrary to Herter (1952), Herreid (1967), and Harmata (1969), I did not examine the temperature preference, or thermopreferendum, of bats under experimental conditions but concluded on it only on grounds of temperatures registered in various natural habitats of the bats. Thus, my observations pertain to the thermopreferendum of the resting bats, either inactive or active metabolically. My first remark concerns the temperatures preferred in winter. Hibernating bats are known to differ as to their requirements for ambient temperatures in their winter quarters, as pointed out, e.g., by Dulić (1958) and by many other authors. This phenomenon can be illustrated by fig. 1, showing temperature amplitudes as recorded in close vicinity of hibernating individuals of various species of bats in Czechoslovakia and Bulgaria (the data have been collected during November to March but mostly during February)