African elephants have posed another puzzle for scientists – they only sleep for two hours a day, making them the least well-rested among mammals, a study says.
Researchers from the UCLA Center for Sleep Research and the non-profit Elephants without Borders tracked two matriarchal elephants at the Chobe National Park in Botswana, and found that these gentle giants are quite the insomniacs, NBC News reports. What’s more amazing is that the elephants had traveled nearly 19 miles in 10 hours without any rest, and managed to stay awake for a record 46 hours straight.
The study notes that the elephants’ ability not to sleep are a new record for a mammal’s sleeping pattern, and is comparable to captive elephants that sleep around five to six hours a day at most.
Jerry Siegel, director of the Center for Sleep Research, said,
The elephants were studied for continuous 35 day periods [from a distance]. Elephants move with their herd and move very frequently, so animals sleeping a lot would be left behind.
The study further observes that the mama elephants did not sleep in the same location daily, and would search for areas with plenty of vegetation, like woodlands and the open savanna, taking care not to cross paths with other elephant herds.
To track the animals, researchers used GPS trackers and “actiwatch implants” to check on the activity levels of both elephants. They found that both females could sleep while on their feet for two days straight, napped only in 20-minute breaks over a night, and kept moving to avoid poachers, predators and anything else that might disturb the herd.
Siegel said, “I have previously shown in 2005 that herbivores sleep less than omnivores and carnivores. Elephants are eating machines. If they were not eating all the time, they wouldn’t be the massive animals they are.”
This data now poses a problem for scientists, as they seem to defy the rule that the bigger an animal, the more sleep it needs. The study shows that the elephants sleepless than the gray whales’ nine hours a day and the giraffes’ 4.6 hours a day. However, other scientists point out that the rule is flawed, anyway.
The researchers in this study do admit that more work needs to be done, particularly when it comes to monitoring male elephants and calves.