Wild Elephants Sleep The Least

Mar 19, 2017 By James H, Young Editor
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Just how many hours of sleep do you need to stay awake the next day?

Supposedly, children and teenagers around ages 6-17 need at least eight hours of sleep. And those who get less than eight, end up getting stressed or tired the next day. Now, imagine that your body can fully function every day with just… two hours of sleep - how would life be like for you?

While many of us human beings are not able to survive with very little sleep, animals in the wild can manage with sleepless nights. For example, horses sleep for an average of three hours. Scientists have found recently that wild African elephants sleep for only two hours each night, making them the lightest sleepers of any mammal. But just how do they do it? Let’s find out.

Tracking Elephants

Well, to start, elephants who lived in captivity were already observed to sleep three to seven hours every night. To compare that to those that live in the wild, scientists tracked two wild African elephants in Botswana for their sleep patterns. 

By placing a motion sensor (similar to a Fitbit) inside their trunks, scientists can track whether the elephants are active or not. The trunk is hardly idle when the elephant is awake, so if the motion sensor is not active for about five minutes, scientists figured that the elephant is asleep.

Scientists also attached gyroscopes to the elephant's collars to track if the animals were sleeping standing up or lying down. Usually while going through a phase of sleep called REM (Rapid Eye Movement) -- a dreaming state, it is hard for animals to stand up as their muscles relax. Results show that these elephants slept an average of two hours a night, that they slept in different places every night and usually between 1 and 6 am, that they experience REM sleep every three to four days, and that they sleep in several discontinuous breaks. 

Reason For Lack Of Sleep?

Scientists have come up with several assumptions for why elephants sleep so little.

First off, wild animals probably have to be more active and alert than captive animals, as they have to watch for predators. Another reason might be that the elephants have to spend more time to find food since they are large animals. Also, they might sleep for short bursts throughout the day and sleep for a longer time in the night, but the short snoozes in the day might not have been tracked.

It has been widely believed that REM sleep helps in memory consolidation, which means converting short-term memory into long-term memory. However, elephants are well known for their long-term memories, and hence this recent finding goes against our understanding of sleep.

No one quite knows how elephants manage their lives with two hours of sleep. One thing’s for sure though, the elephant’s ability to sleep two hours is something that most of us may like to have!


Sources: BBC, howsleepworks, sciencerecorder