jude via Flickr Creative Commons // CC BY 2.0
jude via Flickr Creative Commons // CC BY 2.0

Wild Elephants May Get the Least Sleep of Any Mammal

jude via Flickr Creative Commons // CC BY 2.0
jude via Flickr Creative Commons // CC BY 2.0

Sleep is a funny thing. We literally can’t live without it, yet there’s still a lot about it that we just don’t understand. Now, new insight into the unconscious hours of African elephants may muddle the matter further, as a study in the journal PLOS One finds that the massive beasts spend barely any time asleep at all.

Scientists have hypothesized that the size of a mammal’s body is negatively associated with the amount of time it spends sleeping; in other words, big animals sleep less than small ones. Current record holders for shortest sleep time are the domestic horse (two hours, 53 minutes) and pony (three hours, 20 minutes).

While generally accepted, the theory has been tough to test, since you can’t exactly invite a whale into the laboratory for an overnight sleep study. Many studies have focused on captive animals for this reason, but there’s often a big difference between the lives of animals in zoos and those roaming free.

To check in on the sleeping habits of the wild African elephant (Loxodonta africana), researchers focused on the middle-aged matriarchs of two different herds. The scientists fitted each elephant with a collar to monitor her location and body position. (Elephants have two sleeping positions: lying down, which allows for deep REM sleep, and standing up, which is more of a shallow-sleep, nap-type situation.) They also implanted a small movement tracker at the tip of her trunk. Then both elephants were released to go about their lives as usual. The researchers took the trackers back 35 days later and reviewed the data they’d collected.

As it turns out, the elephants had been living remarkably busy lives. Like high-powered businesspeople, they rarely lay down—just once every three or four nights. The rest they did get—mostly while standing—was shallow and brief, averaging about two hours per night. Some nights they just kept walking and never slept at all.

“Studies of sleep in captive elephants have shown that they sleep for four to six hours per day,” study co-author Paul Manger of the University of the Witwatersrand said in a press statement. “However, the current study shows that in their natural habitat, wild, free-ranging elephants sleep only for two hours per day, the least amount of sleep of any mammal studied to date.”

What this means for elephants and other mammals remains to be seen. With just two participants, this was a very small study, and the researchers only tracked movement, not sleep itself. One of the two elephants was also caring for a calf, a responsibility that likely cut into her sleeping time.

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iStock
Good News, Dog Parents: You Can Teach Puppies as Well as Their Canine Moms Can
iStock
iStock

If you’ve ever adopted a puppy, you probably know how frustrating it can be to teach your new family member the basic tenets of common decency, like not to pee on the carpet or tear up a whole roll of toilet paper.

In other areas, though, pups are rather impressive learners, capable of mimicking some human behaviors. In fact, for some tasks, they learn just as effectively from watching people as they do from watching other dogs, including their own mothers, a new study in Nature revealed.

Researchers from Hungary and the UK took 48 young puppies of various breeds and studied the conditions under which they can be taught to open a puzzle box containing food. The experiment revealed that the puppies were able to learn how to open the box regardless of whether the task was first demonstrated by a person, their mother, or an unfamiliar dog. In other words, not only are puppies capable of social learning, but they're able to learn tasks from humans they don't know—in this case, the experimenter.

However, researchers were surprised to learn that the puppies were more likely to learn how to open the box by watching an unfamiliar dog than by watching their own mothers. That may be because puppies spend more time looking at—and thus, learning from—an unfamiliar dog that intrigues them. This differs from other species such as kittens, which “learn to press a lever for food more rapidly from their mother than from an unfamiliar adult,” the study notes.

In addition, the puppies were able to perform the task again after a one-hour break, indicating that they had retained some memory of the learning experience.

The ability of dogs to learn from humans has been recorded in previous research. A 2015 study revealed that dogs learn better by demonstration (or the “do as I do” method) than training techniques that involve a system of punishments and rewards. The "do as I do" approach probably isn't the most practical method of teaching your pup to do its business outside, but if you already have an adult dog at home, your new puppy can follow the older dog's lead and learn by example.

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Michael Hutchinson
Spiders Can Fly Through the Air Using the Earth's Electric Field
A spider exhibiting ballooning behavior.
A spider exhibiting ballooning behavior.
Michael Hutchinson

Every so often, otherwise Earth-bound spiders take to the air. Ballooning spiders can travel hundreds of miles through the air (and, horrifyingly, rain down on unsuspecting towns). The common explanation for this phenomenon is that the spiders surf the wind on strands of silk, but there may be other forces at work, according to a new study spotted by The Atlantic.

In the research, published in Current Biology, University of Bristol scientists argue that Earth's atmospheric electricity allows spiders to become airborne even on windless days. To test their hypothesis, the researchers exposed spiders in the lab to electric fields similar to those naturally found in the atmosphere.

When the electric field was turned on, the spiders began to exhibit behavior associated with ballooning—they "tiptoed" on the ends of their legs, raised their abdomens, and released silk. Spiders only exhibit this behavior when ballooning. And when they did become airborne, the spiders’ altitude could be controlled by turning the electric field on and off. When the electric field was on, they rose through the air, but when it was off, they drifted downward.

This provides a potential explanation for why spiders take to the skies on certain days but not others, and how they can fly in calm, windless weather— something scientists have puzzled over since the early 19th century. (Even Darwin was flummoxed, calling it "inexplicable," The Atlantic notes.) However, the researchers note that these electric fields might not be totally necessary for ballooning—wind alone might work perfectly fine on some days, too. But understanding more about when and how spiders become airborne could help us predict when there will be large masses of arachnids flying through the skies (and hide).

[h/t The Atlantic]

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