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New Research Finds that Kangaroos are Left-Handed

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Nine out of 10 humans may favor their right hands, but—according to a paper that was recently published in Current Biology—most kangaroos have the opposite preference.

Researchers from Russia, Australia, and Tanzania monitored 38 eastern gray kangaroos (Macropus giganteus, the world’s second-largest species), snapping thousands of photos in the process. Every single animal disproportionately relied on its left hand while “grooming the nose, picking a leaf, or bending for a tree branch.” Meanwhile, red kangaroos (Macropus rufus) displayed a similar bias, as the team observed “significantly more left- than right-handed individuals.”

Other marsupials have a different technique. The study also kept tabs on two wild red-necked wallaby (Macropus rufogriseus) populations. These critters “always used their right paw for strength work, like pulling a branch down, but always brought the leaves to their mouth using their left paw,” ecologist Janeane Ingram says.

In nature, preferring one appendage over another is not at all unusual. Many vertebrates have a dominant side—elephants, for example, are either right- or left-tusked. But this is the first proven case of true handedness in non-primate creatures. As Ingram explains, that particular trait was believed to have “evolved primarily in humans” and our closest relatives. Kangaroos and wallabies, though, represent a very different mammalian group.

Given this, we may need to amend long-standing assumptions about how, when, and why righties and lefties first appeared. Like kangaroos, people are built for getting around on two legs—which leads Yegor Malaschichev, a Saint Petersburg State University zoologist, to suspect that bipedal lifestyles are the chief driving force behind the evolution of handedness.

Interestingly, the hopping marsupials show hand-based favoritism to an extent matched only by Homo sapiens (even our fellow apes lack such blatant partiality). “[We] are not alone in the universe,” declares Malaschichev, “we are two—humans and kangaroos.” 

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Animals
25 Shelter Dogs Who Made It Big
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If you’ve been thinking of adding a four-legged friend to your brood and are deciding whether a shelter dog is right for you, consider this: Some of history’s most amazing pooches—from four-legged movie stars to heroic rescue dogs—were found in animal shelters. In honor of Adopt-a-Shelter-Dog Month, here are 25 shelter dogs who made it big.

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This High-Tech Material Can Change Shape Like an Octopus
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Octopuses can do some pretty amazing things with their skin, like “see” light, resist the pull of their own sticky suction cups, and blend in seamlessly with their surroundings. That last part now has the U.S. Army interested, as Co.Design reports. The military branch’s research office has funded the development a new type of morphing material that works like an octopus’s dynamic skin.

The skin of an octopus is covered in small, muscular bumps called papillae that allow them to change textures in a fraction of a second. Using this mechanism, octopuses can mimic coral, rocks, and even other animals. The new government-funded research—conducted by scientists at Cornell University—produced a device that works using a similar principle.

“Technologies that use stretchable materials are increasingly important, yet we are unable to control how they stretch with much more sophistication than inflating balloons,” the scientists write in their study, recently published in the journal Science. “Nature, however, demonstrates remarkable control of stretchable surfaces.”

The membrane of the stretchy, silicone material lays flat most of the time, but when it’s inflated with air, it can morph to form almost any 3D shape. So far, the technology has been used to imitate rocks and plants.

You can see the synthetic skin transform from a two-dimensional pad to 3D models of objects in the video below:

It’s easy to see how this feature could be used in military gear. A soldier’s suit made from material like this could theoretically provide custom camouflage for any environment in an instant. Like a lot of military technology, it could also be useful in civilian life down the road. Co.Design writer Jesus Diaz brings up examples like buttons that appear on a car's dashboard only when you need them, or a mixing bowl that rises from the surface of the kitchen counter while you're cooking.

Even if we can mimic the camouflage capabilities of cephalopods, though, other impressive superpowers, like controlling thousands of powerful suction cups or squeezing through spaces the size of a cherry tomato, are still the sole domain of the octopus. For now.

[h/t Co.Design]

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