Posted by: Footler PJ16 OCT 2013
THE only primates known to use hibernation as a survival strategy are three species of dwarf lemur found in Madagascar.
Two of these are Crossley’s dwarf lemur (Cheirogaleus crossleyi) and Sibree’s dwarf lemur (C sibreei). Both live on the eastern side of the island, where their habitat includes high altitude forests. Relatively little is known about them, but they seem to hibernate burrowed into the soft forest floor, where their body temperatures remain fairly constant.
The third species is the fat-tailed dwarf lemur (C medius), a tropical tree-dweller found on the island’s western side. It hibernates in tree holes to survive the island’s long dry season when trees drop their leaves and food and water are in short supply.
Researchers attached electrodes to the scalps of fat-tailed lemurs and monitored them in their nests. They also studied non-torpid animals sleeping in captivity. They found that the hibernating fat-tailed lemur’s body temperature fluctuated by as much as 25C during a day depending on the temperature of the outside air.
These lemurs also went for days without the slow-wave, low-amplitude brain activity associated with deep sleep and showed periods of brain activity consistent with the phase of sleep known as rapid eye movement (REM) sleep. Among other things, the researchers want to know how thermoregulation as a function of sleep relates to the sleeping state of the lemurs.
By comparing the hibernation of the three dwarf lemurs (our closest genetic relatives known to hibernate) and other animals that hibernate, researchers hope to clarify what precisely sends animals into standby mode.
In future it may be possible to put humans into a similar state that could help patients who have suffered head trauma or heart attacks, extend the shelf life of transplant organs or even be useful for long-distance space travel.