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How Bats Avoid Hitting Obstacles With Echolocation

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Bats fly through complete darkness without bumping into cave walls or other obstacles. While researchers know they use echolocation to get around, how exactly they forge clear paths through complicated environments like caves and forests hasn’t been well understood. A new study by scientists at the University of Antwerp and the University of Bristol finds that bats navigate in the dark using a fairly simple mechanism. Writing in journal PLOS Computational Biology, they report that bats merely listen for the largest echo, and turn away from it. 

The paper argues that it would be practically impossible for bats to interpret all the echoes coming from numerous obstacles in cluttered spaces. To find an alternative explanation, the researchers used 2D and 3D models of simulated bat behavior in real forests and other complicated spaces. They hypothesize that rather than creating a 3D reconstruction of the environment using echolocation, bats rely on a quicker method of finding their way. They compare the volume of echoes in their right and left ears, and turn away from the louder echo, since that obstacle would presumably be nearer. They found that in the virtual model, this method allowed bats to avoid obstacles using just the first millisecond of the echo as a signal. 

Since this is only a computational model of bat behavior, it will no doubt need to be further confirmed by experiments with actual bats. 

Fascinated by echolocation? Bats can also use it to interfere with each other’s signals when competing for food

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