Israeli researchers discover that mouse-tailed bats can hibernate at constant warm temperatures, the first time that a mammal has been shown to do so. Sharon Reich reports.
The sleeping habits of these tiny bats could change what we know about mammal hibernation. Traditionally, it's been thought that hibernation occurs only in low temperatures, as mammals sleep through cold winters maintaining low heart rates and body temperatures. But a team of Israeli researchers suggest that hypothesis is wrong. Tel Aviv University Professor Noga Kronfeld-Schor and Dr. Eran Levin were trying to find where these bats disappear to every winter. They discovered them hibernating in warm caves in the Syria-African Rift, with temperatures of 68°F - 20 degrees Celsius. From October to February, the bats were in a deep sleep, breathing once every 15-30 minutes, expending very little energy. (SOUNDBITE) (English) CHAIR OF DEPARTMENT OF ZOOLOGY AT TEL AVIV UNIVERSITY, PROFESSOR NOGA KRONFELD-SCHOR, SAYING: "The surprising thing was that these animals hibernate at high temperatures. This changes the whole concept of hibernation because people consider hibernation as a strategy to cope with very cold winter conditions, with snow, no food available. And here we have bats hibernating at warm temperatures, which is really surprising." The team monitored the bats' behaviour and body temperatures in the caves. And also brought bats back to the lab to measure their metabolism and water loss. On average, the bats skin temperature dropped to 22 degrees Celsius in the caves and their metabolic rates were at a minimum. (SOUNDBITE) (English) CHAIR OF DEPARTMENT OF ZOOLOGY AT TEL AVIV UNIVERSITY, PROFESSOR NOGA KRONFELD-SCHOR, SAYING: "What we found was that these bats do not hibernate in just any cave. They hibernate in specific caves along the Syrian-African Rift Valley where very hot and humid air comes from the ground. And we think that they choose these specific caves because temperature never drops below 20 degrees Celsius ... Usually they are exposed to much higher temperature and probably the winter in Israel although it's very mild is still too cold for them to be active." The discovery may pave the way for better conservation of this insect eating bat species, which plays an important role in natural pest control.