In a first-of-its-kind study, researchers monitored two African elephants in the wilds of Chobe National Park in Botswana for 35 days to determine how much sleep they got each night.
Studies have been done previously on captive elephants, which sleep three to four hours a day and usually lying down, but until now, scientists were unsure about how much sleep African elephants got in the wild.
Paul Manger of the University of Witwatersrand, South Africa, and his colleagues anesthetized two elephants and inserted Fitbits into their trunks and fitted each with a GPS collar with a gyroscope around their necks.
“We reasoned that measuring the activity of the trunk, the most mobile and active appendage of the elephant, would be crucial, making the reasonable assumption that if the trunk is still for five minutes or more, the elephant is likely to be asleep,” Manger told Phys.Org.
The gyroscope determined whether they were lying down or standing.
What they discovered when they retrieved the Fitbits and collars was that the African elephants got about two hours of sleep a day, usually during the early morning hours, and would regularly go nearly two days without sleep, according to the study released in the journal PLOS ONE.
The study also showed that the elephants slept mostly standing up, and would sleep lying down only every three to four days.
Before the latest elephant sleep stats, horses were the record-holders among mammals for the shortest sleep requirement at 2 hours, 53 minutes, Manger says. Donkeys weren’t far behind at 3 hours, 20 minutes. Game rangers familiar with wild African elephants, however, claimed the pachyderms virtually never slept.
So why is the amount of sleep by an African elephant in the wild important?
“Understanding how different animals sleep is important for two reasons,” Manger told Phys.Org.
“First, it helps us to understand the animals themselves and discover new information that may aid the development of better management and conservation strategies, and, second, knowing how different animals sleep and why they do so in their own particular way, helps us to understand how humans sleep, why we do, and how we might get a better night’s sleep.”
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