Humans need less sleep than other mammals, yet their slumber is more efficient, said researchers at Duke University in North Carolina.

In their study, the scientists researched sleep patterns of hundreds of animals. They discovered humans sleep for shorter periods of time compared to other animals.

The study also concluded that a human's sleep is of higher quality. A deeper stage of sleep, called rapid eye movement sleep, or REM, makes up 25 percent of a human's sleep. In primates like lemurs or monkeys, REM sleep does not reach the five percent mark.

"Humans are unique in having shorter, higher quality sleep," said David Samson, a study co-author.

Samson's research team found that humans can prosper with an average of seven hours of sleep a day. Other primates need as many as 14 to 17 hours of sleep.

Samson said human sleep habits evolved during prehistoric times. Human ancestors moved from sleeping in trees to sleeping on the ground. Better sleeping habits resulted in better sleep in a shorter amount of time.

美国北卡罗来纳州杜克大学的研究人员表示，人类比其它哺乳动物需要的睡眠更少，然而人类的睡眠更为有效。

在他们的研究中，科学家们研究了数百种动物的睡眠规律。他们发现，人类相对于其它动物睡眠时间更短。

该研究还得出结论认为，人类睡眠质量更高。睡眠的一种深入阶段被称为快速眼动睡眠，它占到了人类睡眠的25%。在狐猴或猴子之类的灵长类中，快速眼动睡眠未能达到5%。

这项研究的合著者大卫·萨姆森表示，“人类具有更短更高质量的睡眠，这是独一无二的。”萨姆森的研究团队发现，人类平均每天睡7个小时就能重新恢复。其它动物需要多达14到17小时的睡眠。

萨姆森表示，人类睡眠习惯在史前时期发生演变。人类祖先从睡到树上转变为睡到地上。更好的睡眠习惯导致短时间就能睡得更好。