Contents
It has traditionally been thought that the sleep patterns of humans and their closest primate relatives are very similar. Researchers from Duke University (USA) have proposed an alternative hypothesis – they argue that our sleep is shorter and deeper than the sleep of many animals.
Scientists have scoured a wealth of scientific data and literature to compile a database of sleep patterns in hundreds of different mammalian species, including primates (21 species), including lemurs, orangutans, chimpanzees and, of course, humans.
Comparing the sleep of different animal species, scientists have found that humans sleep much less than many mammals. Among primates, for example, some species of macaques and lemurs sleep 14-17 hours a day.
Pass the tests
- Are you getting enough sleep?
It is also noteworthy that human sleep is more “efficient”, that is, a large proportion of it falls on the deep phases. The so-called phase of rapid eye movements (REM sleep), during which we see dreams, takes up almost 25% of the total sleep time. In many primates, the duration of this phase does not exceed 5% of sleep time.
“Humans are unique in this regard because of relatively short, but more “quality” sleep, – said one of the authors of the study, anthropologist David Samson (David Samson), who works at Duke University. In the past, Samson has already studied primate sleep: in the process of working on his dissertation, he observed the sleep of orangutans for a total of 2000 hours.
Read more:
- Why do you want to sleep all the time?
At the same time, the short duration of our sleep is not associated with the use of artificial lighting. A recent study among hunter-gatherer tribes living without any modern technology found that they sleep even slightly less than people in developed countries.
Researchers believe that the change in the structure of sleep in our ancestors during evolution is associated with the transition from sleeping in trees to sleeping on the ground.
David Samson believes that when primitive people began to sleep on the ground, they preferred to lie down closer to the fire and sleep in large groups in order to keep warm and keep out predators – leopards, hyenas and others. In such a situation, shorter sleep became evolutionarily advantageous. In addition, the ancient people freed up more time that they could devote to mastering new skills and developing social ties. Deeper sleep helped consolidate the acquired knowledge, improved memory and mental abilities in general.
Подробнее см. D. Samson & C. Nunn «Sleep intensity and the evolution of human cognition», Evolutionary Anthropology, vol. 24, № 6, November/December 2015.