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Media Article # 395
Wednesday, June 23, 2004
Primates Found Hibernating in Tropical Heat
LONDON (Reuters) - Bears and groundhogs escape the cold winter months by burrowing underground and hibernating but scientists said on Wednesday the trait is not limited to animals living in chilly climates.
Researchers in Germany have found that lemurs in Madagascar in the Indian Ocean, where winter daytime temperatures rise above 30 degrees Centigrade (86F), hibernate in tree holes for seven months of the year.
"To our knowledge, our findings are the first physiological confirmation of prolonged hibernation by a tropical mammal as well as the first proof of hibernation in a primate," said Gerhard Heldmaier, of Philipps University in Marburg, Germany, in a report in the science journal Nature.
"This study shows hibernation has nothing to do with cold -- it may happen even in a hot or warm environment," he added.
Rather than escaping chilly temperatures, Heldmaier and his colleagues said the Madagascar fat-tailed dwarf lemurs were bedding down and preserving energy because of less food during the dry season.
"It is an adaptation to get through periods when food is scarce. It is a mechanism of energy saving," said Heldmaier.
Bears usually experience a drop in temperature when they snuggle down for the winter slumber.
Heldmaier and his team found that the lemur's body temperature fluctuates by as much as 20 degrees Centigrade and depends on how well the tree holes are insulated. If they are not well insulated, temperature varies widely.
"No other hibernators show such a bouncing of body temperature between 15 and 33 degrees Centigrade," said Heldmaier.