Hibernating lemurs hint at the secrets of sleep

Posted on September 5, 2013
Hibernating lemurs hint at the secrets of sleep

Hibernating lemurs hint at the secrets of sleep
A young fat-tailed dwarf lemur living at the Duke Lemur Center shows the characteristic calorie-packed tail the animal uses to fuel up to seven months of hibernation. Credit: David Haring, Duke Lemur Center

By studying hibernation, a Duke University team is providing a window into why humans sleep. Observations of a little-known primate called the fat-tailed dwarf lemur in captivity and the wild has revealed that it goes for days without the deepest part of sleep during its winter hibernation season. The findings support the idea that sleep plays a role in regulating body temperature and metabolism.

Despite decades of research, why we sleep is still a mystery. Theories range from conserving energy, to processing information and memories, to removing toxins that build up when we’re awake.

“If we spend nearly a third of our lives doing it, it must have some specific purpose,” said lead author Andrew Krystal, a sleep researcher at Duke.

One theory is that sleep helps regulate body temperature and metabolism. In a study appearing Sept. 4 in the journal PLOS ONE, researchers have found support for the idea in the fat-tailed dwarf lemur (Cheirogaleus medius), a squirrel-sized primate native to the African island of Madagascar.

The closest genetic relatives to humans that are known to hibernate, fat-tailed dwarf lemurs spend up to seven months each year in a physiological state known as torpor, where the regulation of body temperature stops and metabolism slows down.

In torpor, these lemurs can drop their heart rate from 120 beats per minute to a mere 6, and breathing slows to a crawl. Instead of maintaining a steady body temperature like most mammals, their bodies heat up and cool down with the temperature of the outside air, fluctuating by as much as 25 degrees in a single day.

Read more at: Phys.org