Hibernating lemurs hint at the secrets of sleep. Duke Today, September 4, 2013. 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. Picked up by WUNC, National Geographic, NBC News, US News and World Report, Huffington Post, Futurity, Discovery News and the Los Angeles Times.