It is official: elephants are the masters of the power nap and this is baffling scientists.
New research‚ released on Wednesday night‚ proves that elephants are the mammals that sleep the least.
Studies of two matriarch elephants in the Chobe National Park in Botswana revealed that on average‚ they slept two hours a night. This is less than elephants in zoos‚ which on average sleep double that a night.
They even sleep less than horses‚ that get about two and three quarters of an hour of shuteye a night. And far less than the biggest sleeper in the mammal kingdom — the little brown bat — which sleeps 18 hours a day.
Scientists from the University of the Witwatersrand‚ the University of California‚ Los Angeles‚ and the NGO Elephants Without Borders were able to peek into the slumber habits of pachyderms through using Fitbit-like activity monitors that were surgically placed in their trunks.
“If you watch elephants they are always moving their trunks‚ so when they are not moving their trunks it is safe to say they are asleep‚” explained Professor Paul Manger‚ from the School of Anatomical Sciences at Wits University.
The team also placed GPS collars with a gyroscope around their necks.
The scientists discovered that the two elephants only entered a deep sleep REM state once every three to four days‚ which came as a surprise.
“REM sleep (or dreaming) is thought to be important for consolidating memories‚ but our findings are not consistent with this hypothesis of the function of REM sleep‚ as the elephant has well-documented long-term memories‚ but does not need REM sleep every day to form these memories‚” Manger said in a statement.
Their data also suggested‚ explained Manger‚ that environmental conditions like temperature and humidity were related to when an elephant fell asleep‚ rather than light. He believes that this could also assist in understanding how humans sleep.
It also appears that elephants can go long periods without sleep‚ sometimes as long as 48 hours‚ while moving long distances through the night.
Manger now wants to increase the study sample‚ attaching activity trackers to elephant bulls who roam more.
Elephant experts have pointed out that large bull elephants often lean against trees to sleep rather than lie down‚ as it would be difficult for them to get back up.
The research found that elephants only entered REM sleep when lying down.
“It would be nice to study forest elephants‚ desert elephants and Indian elephants. There are a lot of things to do‚” said Manger.
– TMG Digital/The Times