Many mammals -- and some birds -- escape the winter by hibernating for three to nine months. This period of dormancy permits species which would otherwise perish from the cold and scarce food to survive to see another spring. The Middle East, with temperate winters, was, until recently, considered an unlikely host for hibernating mammals. New research published online on March 4, 2015 in the Proceedings of the Royal Society of London by Tel Aviv University (TAU) researchers is set to not only correct this fallacy, but also change the very concept of hibernation. Professor Noga Kronfeld-Schor, Chair of the Department of Zoology at TAU's Faculty of Life Sciences, and doctoral student Dr. Eran Levin found two species of mouse-tailed bat (the Rhinopoma microphyllum and the R. Cystops) hibernating at the unusually warm and constant temperature of 68°F in caves in Israel's Great Rift Valley. From October to February, these bats were discovered semi-conscious, breathing only once every 15-30 minutes, with extremely low energy expenditures. "Hibernation in mammals is known to occur at much lower temperatures, allowing the animal to undergo many physiological changes, including decreased heart rate and body temperature," said Professor Kronfeld-Schor. "But we have found these bats maintain a high body temperature while lowering energy expenditure levels drastically. We hypothesize that these caves, which feature a constant high temperature during winter, enable these subtropical species to survive on the northernmost edge of their world distribution." The researchers monitored the activity of the bats during this period and found that they neither fed nor drank, even on warm nights when other bat species were active in the same caves.
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