CAN EXTERNAL RADIOTRANSMITTERS BE USED TO ASSESS BODY-TEMPERATURE ANDTORPOR IN BATS

We tested externally applied, temperature-sensitive, radiotransmitters for determining the body temperature of big brown bats (Eptesicus fus cus) in various ambient temperatures (2-26 degrees C). There was a sli ght, but significant, effect of ambient temperature on skin temperatur e (measured by the transmitters), but skin temperature accurately refl ected rectal temperature in torpid and active bats, and it was never > 3.3 degrees C below rectal temperature. External radiotransmitters are , thus, useful in studies of torpor in bats, even when only small decr eases in body temperature occur.