Scientists find tropical animal that hibernates through hot summer

Scientists have found the first tropical mammal that hibernates through hot winter months, when temperatures can fluctuate around an average of 30C.

Scientists have found the first tropical mammal that hibernates through hot winter months, when temperatures can fluctuate around an average of 30C.

The Madagascan fat-tailed dwarf lemur (Cheirogaleus medius) spends up to seven months of the year asleep in a tree hole, rivalling the hibernating abilities of northern mammals.

A research team led by Kathrin Dausmann of Philipps-University in Marburg, Germany, found that the lemur - a nocturnal primate - hibernates in poorly insulated holes where the ambient air temperature can vary wildly. Field studies found that the body temperature of the lemur during hibernation varies to an extent previously not known in mammals.

The findings, reported in the journal Nature , suggest that the lemur hibernates in order to allow its body temperature to fluctuate with the environment rather than trying to control it with its own metabolism, which it has to do when awake and active.

Lemurs who did manage to find well-insulated tree holes seemed to be aroused from their slumber at regular intervals and did not experience such wildly varying body temperatures. This may indicate the hibernation was a way of avoiding the temperature extremes experienced in the tropics.

"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," the researchers write.