But researchers from Tel Aviv University recently found two species of the mouse-tailed bat hibernating in caves in Israel's Great Rift Valley. The bats' sleeping quarters featured a constant temperature of 68 degrees Fahrenheit. It's the first time a mammal has been found hibernating in consistently warm temperatures.
The bats -- Rhinopoma microphyllum and R. Cystops -- were observed hibernating from October to February. During their time asleep in the caves, researchers found the hibernating species only breathed once every 15 to 30 minutes.