You may not have noticed, but most mammals need twice as many hours of shuteye each night as you do.
That’s what researchers from Duke University discovered after examining the sleep patterns of hundreds of mammals, including 21 primate species.
And there is a reason for the difference.
“Humans are unique in having shorter, higher quality sleep,” study co-author and anthropologist David Samson said in a news release from the North Carolina-based university.
The research team found that people sleep an average of seven hours a night, while some other primates require as many as 14 to 17 hours a night.
People spend less time in light stages of sleep and more time in the deeper stages of slumber, according to the researchers.
The findings were published Dec. 14 in the journal Evolutionary Anthropology.
Humans’ shorter, more efficient sleep likely developed after they left the trees and started sleeping on the ground near fire and in larger groups, to keep warm and reduce the risk from predators. This enabled humans to get the most sleep in the shortest time possible, Samson explained.
Devoting fewer hours to sleep also left more time for activities, such as learning new skills and social bonding, and deeper sleep helped maintain those skills, improve memory and increase brainpower, Samson added.
The U.S. National Institute of Child Health and Human Development has more about sleep.