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May 12, 2025—Cute, pug-faced pets could not survive in the wild. Plus, biodegradable robots and scientists create gold from lead (for a microsec). —Andrea Gawrylewski, Chief Newsletter Editor | | An aerial view of an ice floe in the Canadian High Arctic on September 27, 2025. Clement Sabourin/AFP via Getty Images | | Japanese Chin. Anna Koldunova/Alamy Stock Photo | | Evolutionary biologists compared skull sizes of different pets and wild animals. They collected skull measurements for 1,810 animals from CT scans of pets from animal hospitals and specimens from natural history museums (mixed and purebred breeds), and data from hundreds of skulls of wild animals from the Canidae and Felidae families–domestic dogs' and cats' wild relatives and same family. By creating 3D models of each skull and comparing their anatomy the researchers found that brachycephalic animals—those with short round faces and pushed up noses, like pugs and Persian cats—have more in common with each other than with their wild ancestors. Why this matters: They're cute, yes. But brachycephalic pets could not survive in the wild. Through selective breeding, their palates have been tilted up, which has drastically shrunk their nasal region and restricted their airways as well as the space at the back of their throat. Some Persian cats actually lack nasal bones entirely. Persian cats and pugs often have so much difficulty breathing that they often require corrective surgery. Plus, they frequently suffer from problems with their eyes, teeth and neurological systems. Because they don't get enough oxygen, they can't tolerate heat or exercise. What the experts say: "If you isolate the gene pool with inbreeding and force massive selection pressures, you can produce a remarkable amount of diversity in a short period of time," says Abby Grace Drake, an evolutionary biologist at Cornell University. While this is fascinating from an evolutionary biology point of view, she and other experts do not think it is worth the health consequences for the animals. Their advice: adopt a mixed breed from a shelter. | | Engineers built a robotic arm, and a joystick-like controller to operate it, from natural, biodegradable materials. Their starting materials were cellulose layers derived from cotton pulp, to which they added glycerol for flexibility. They then dried the layers to make them strong. To build robotic sensors, the team used an electrically conductive gelatin extracted from pork, in which the flow of ions changes when stretched, bent or pressed. They folded the flat cellulose films and sensors into 3D structures. After extensive testing (the soft robots held up well), the researchers buried the materials near their research campus and the robots disintegrated in the soil within weeks. Why this is interesting: Biodegradable robots could one day handle hazardous waste in the environment and then dissolve in the same spot. They might also be used in surgeries and then safely break down inside the body. What the experts say: "If we truly want to have a sustainable robot that goes outside in nature," says Florian Hartmann, a materials scientist at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany, "we also need to think of electronics or power supplies, or even batteries, that are biodegradable." | | - For most of the last week, India and Pakistan engaged in intense missile and drone strikes until a ceasefire was announced on Saturday morning. The stakes are high, as the two nations each have about 170 nuclear weapons. "A nuclear war between India and Pakistan could kill one to two billion people through starvation in the two years after the war," write Alan Robock and Lili Xia, both professors of environmental science at Rutgers University. "The story of nuclear weapons will have an ending, and it is up to us what that ending will be. Will it be the end of nuclear weapons, or will it be the end of us? One of these things will happen," they say. | 5 min read
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In 2017, a group of Hungarian animal behavioral researchers surveyed thousands of dog owners. They found that mixed-breed dogs seemed to be slightly more trainable, but less well-behaved and less calm compared with purebreds. On the whole, though, fewer mixed breed owners do train their dogs, according to the results. The scientists noted that "dog keeping practices," that is, how owners care for their pets, could account for most differences observed in dog behavior (mixed vs. purebred). If you're a dog lover like me, then there's really only one way to "keep" all dogs: Treats, pets, and unconditional love. | | Tell me about your family dogs, their breeds, and your favorite stories of their behavior: newsletters@sciam.com. See you tomorrow! —Andrea Gawrylewski, Chief Newsletter Editor | | | | |
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