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When you consider animals that hibernate, dwarf lemurs probably aren’t the first mammal that comes to mind. They live in the tropics and most hibernating species live in areas where temperatures drop to an inhabitable level.
Although dwarf lemurs might not need to protect themselves from the cold, they may hibernate for the same essential reasons as their temperate mammalian brethren: the limited availability of resources such as food and water.
Unlike bears and ground squirrels, western dwarf lemurs hibernate in tree holes for up to seven months to survive western Madagascar’s long dry season—a time when temperatures top 85 degrees, trees drop their leaves, and food and water are in short supply.
Eastern dwarf lemurs (Cheirogaleus sibreei and Cheirogaleus crossleyi), on the other hand, live in higher altitudes where temperatures can drop below freezing. These primates choose to hibernate in well-insulated burrows for three to six months each year.
Researchers discovered this by trapping and fitting the squirrel-sized animals with temperature-sensitive radio collars before the start of the hibernation season, allowing them to find the lemurs’ underground burrows and monitor their body temperature once hibernation began.
Their findings are published this week in an open-access article in Scientific Reports.
Hibernating animals tend to breathe more slowly, drop their heart rate, and lower their body temperature, becoming inactive for days at a time. Dwarf lemurs are no exception.
“To the casual observer, it looks for all the world as if the animals are dead. Their bodies are cold, they are utterly still and they take a breath only once every several minutes or so,” says co-author Anne Yoder, director of the Duke Lemur Center.
“Exactly what triggers hibernation is still an open question," says lead author Marina Blanco, also from the Duke Lemur Center. “Maybe these lemurs, though they live in the tropics, look more like temperate hibernators than we thought.”
Image courtesy of Duke University