Social Media Sidebar


Please sign up, comment on articles and bring your friends!

Current poll

PlanetTech is asking:

What do you think about our new web site?

Love it, indeed
Really good solution
Same as old one
The old one was better
This is a new option

Quote of the day

Just because something doesn’t do what you planned it to do doesn’t mean it’s useless.


Thomas Edison

Compared with other primates, human sleep is short and deep

Posted in Science on 19th Dec, 2015 08:16 PM by AlexMuller

Over the past few million years, the ancestors of modern humans became dramatically different from other primates. Our forebears began walking upright, and they lost much of their body hair; they gained precision-grip fingers and developed gigantic brains.

But early humans also may have evolved a less obvious but equally important advantage: a peculiar sleep pattern. “It’s really weird, compared to other primates,” said Dr. David R. Samson, a senior research scientist at Duke University.
In the journal Evolutionary Anthropology, Dr. Samson and Dr. Charles L. Nunn, reported that human sleep is exceptionally short and deep, a pattern that may have helped give rise to our powerful minds. Until recently, scientists knew very little about how primates sleep.
To document orangutan slumber, for example, Dr. Samson once rigged up infrared cameras at the Indianapolis Zoo and stayed up each night to watch the apes nod off.
 The researchers found that the time each primate species spends asleep generally corresponded to its physical size.
In the new study. Dr. Samson and Dr. Nunn combined that information with studies of 19 other primate species. The researchers found wide variations in how long the animals slept. Mouse lemurs doze for seventeen hours a day, for example, while humans sleep just seven hours or so a day, “the least of any primate on the planet,” said Dr. Samson.
The scientists looked for factors that could explain the differences. Compared with big mammals, for example, smaller species tend to sleep more during the day and in short bouts, perhaps because they need to eat many times a day.
Dr. Samson and Dr. Nunn found that the time each primate species spends asleep generally corresponded to its physical size, along with other factors, such as the average number of primates in a group.
The one big exception: humans. We sleep a lot less than one would predict based on the patterns seen in other primates. From time to time while sleeping, we slip into REM sleep and dream. All told, we spend about 22 percent of sleep in REM, the highest ratio of REM to total sleep in any primate, the researchers reported.
Dr. Samson and Dr. Nunn have an explanation for how humans ended up sleeping so little, and so often in REM. Over tens of millions of years, they assert, changes in our ancestors’ ecology drove the evolution of new sleeping patterns. Humans increasingly have been able to achieve a good night’s sleep.
A number of studies suggest that REM sleep benefits the brain. Some scientists argue that it sweeps out molecular debris, and others say it consolidates new memories into lasting impressions. But it was not easy for our monkey-like ancestors to reach REM sleep. They slept on branches, and their nights were anything but easy. As monkeys try to sleep today, they get roused by winds, tree snakes and the jostling of their fellow primates.
The fossil record suggests that 20 million years ago, the ancestors of humans and other apes changed their sleeping habits because they became too big for branches. Today, no primate that weighs over 60 pounds sleeps on a branch. Instead, chimpanzees, bonobos and their cousins build sleeping platforms each night from sticks and other materials.
Dr. Samson and his colleagues have found that apes take great care in choosing trees to sleep in and the materials to build their platforms. The reason, he suspects, is that apes aim to get the best night’s rest they can.
Dr. Samson and the primatologist Robert W. Shumaker found that orangutans that got to make platforms of foam and other comfortable materials scored better on cognition tests the following day than apes that slept on straw.
Early humans probably slept around fires in large groups, able to ward off predators. The result, said Dr. Samson and Dr. Nunn, was the chance to get an even better night’s rest. Humans were able to fall more soundly asleep and to experience deeper bouts of REM sleep.
Since it took less time to get the benefits of REM sleep, humans were able to get by with less sleep over all than other primates. They gained a few extra waking hours each day, which they might have used to make new tools or share stories.
Dr. Samson replied that the evolution of sleep may be driven by different factors in different groups of species. Figuring out what those factors are will take many more sleepless nights of research.
“These first studies are really exciting indicators that something really profound is going on here,” he said, “but I think the jury’s still out.”

Tags: sleepbiologybrainevolutionapeanimalresearchzoology

Read original article » Back to category



Recent headlines

  • Posted in Medicine on 2018-05-23 01:38:21
    UCLA engineer develops 3D printer that can create more
    Posted in Business on 2018-05-23 01:43:09
    China Launches Satellite Bound for the Far Side of the more
    Posted in Business on 2018-05-21 16:28:10
    Anti-nuclear policies increased global carbon by more
    Posted in Medicine on 2018-05-21 16:22:31
    Magic mushroom treatment improves emotional more
    Posted in Medicine on 2018-05-21 16:18:57
    Antioxidant found to wind back the clock on blood more
Posted in Business on 2013-10-10 01:33
China is working towards a manned lunar mission in more
Posted in Business on 2013-10-20 07:17
Spacex says China is their main competitor for more
Posted in Software on 2013-10-20 06:43
Pirate Bay Browser Clocks 1,000,000 more
Posted in Medicine on 2013-10-10 02:10
Google reportedly investing hundreds of millions into more
Posted in Medicine on 2013-10-14 03:13
Endothelial Cells Can Repair and Regenerate Organs, more
Posted in Science on 01.01.2010
Spacex says China is their main competitor for more
Posted in Science on 01.01.2010
Staring at Your Phone Could Be Making You Short more
Posted in Science on 01.01.2010
Oculus Rift virtual reality headset coming to mobile, more
Posted in Science on 01.01.2010
China is working towards a manned lunar mission in more
Posted in Science on 01.01.2010
Delivering drugs via nanoparticles to target more

Recent Blog Posts

  • Posted by AlexMuller
    In five years quantum computing will be more
    Posted by AlexMuller
    Google partners with Johnson and Johnson to make lower more
    Posted by AlexMuller
    Electron holography microscope with spatial resolution down more
    Posted by AlexMuller
    Lower cost advanced Nuclear power could dominate future US more
    Posted by AlexMuller
    Why Hasn’t AI Mastered Language Translation? more

Login to your Account

Login to your PlanetTech Account here

Remember me

Create a New Account

You just need username and password

The following errors occured:
Verify password:
Remember me