Endurance Tracking - Ultrasonic Clicks - Obesity Drugs
Breedlove, S
Born to run? Endurance running may have evolved to help humans chase down prey
By Kermit Pattison
Since the Stone Age, hunters have brought down big game with spears, atlatls, and bows and arrows. Now, a new study reveals traditional societies around the globe also relied on another deadly but often-overlooked weapon: our legs.
According to a report published today in Nature Human Behaviour, running down big game such as antelope, moose, and even kangaroos was far more widespread than previously recognized. Researchers documented nearly 400 cases of endurance pursuits—a technique in which prey are chased to exhaustion—by Indigenous peoples around the globe between the 16th and 21st centuries. And in some cases, they suggest, it can be more efficient than stealthy stalking.
The findings bolster the idea that humans evolved to be hunting harriers, says Daniel Lieberman, an evolutionary biologist at Harvard University. “Nobody else has come up with any other explanation for why humans evolved to run long distances,” says Lieberman, who adds that he’s impressed with the paper’s “depth of scholarship.”
For decades, some anthropologists have argued that endurance running was among the first hunting techniques employed by early hominins in Africa. Advocates suggest subsequent millennia spent chasing down prey shaped many unique human features, including our springy arched feet, slow-twitch muscle fibers optimized for efficiency, heat-shedding bare skin, and prodigious ability to sweat. The “born to run” idea has become something of an origin story among many endurance athletes.
But a pack of skeptics has dogged the theory. Critics cited the higher energetic costs of running over walking and noted that accounts of persistence hunting among modern foragers are rare.
Yet hints of such pursuits kept popping up as Eugène Morin, an archaeologist at Trent University and co-author of the new paper, scoured the literature for a book he was writing on hunting among traditional societies. As he pored over early accounts by missionaries, travelers, and explorers, he repeatedly found descriptions of long-distance running and tracking.
© 2024 American Association for the Advancement of Science.
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https://www.sciencenews.org/article/tiger-beetles-weaponize-ultrasound-bats
Tiger beetles may weaponize ultrasound against bats
By Jake Buehler
Sounding like a toxic moth might keep some beetles safe from hungry bats.
When certain tiger beetles hear an echolocating bat draw near, they respond with extremely high-pitched clicks. This acoustic countermeasure is a dead ringer for the noises toxic moths make to signal their nasty taste to bats, researchers report May 15 in Biology Letters. Such sound-based mimicry may be widespread among groups of night-flying insects, the scientists say.
At night, bats and bugs are locked in sonic warfare. At least seven major insect groups have ears sensitive to bat echolocation pitches, and many often flee in response. Some moths have sound-absorbent wings and fuzz that impart stealth against bat sonar (SN: 11/14/18). Others use their genitals to make ultrasonic trills — above the range of human hearing — that may startle bats or jam their sonar (SN: 7/3/13).
Previous research suggested some tiger beetles — a family of fast-running, often strikingly colored predatory beetles with strong jaws — also make high-pitched clicks as a response to human-made imitations of bat ultrasound. So Harlan Gough, a conservation entomologist now at the U.S. Fish and Wildlife Service in Burbank, Wash., and his colleagues set out to answer why.
The researchers collected 19 tiger beetle species from southern Arizona and brought them into the lab. They tethered the insects to a metal rod and prompted them to fly. The team then filmed and recorded audio to see how the beetles responded to playback of a bat clicking sequence that immediately precedes an attack. Right away, seven of these species — all nocturnal fliers — pulled their hard, case-like forewings into the path of their beating hindwings. The resulting collisions made high-pitched clicking noises.
© Society for Science & the Public 2000–2024.
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https://www.nature.com/articles/d41586-024-01433-6
Experimental obesity drug packs double punch to reduce weight
By Asher Mullard
With obesity drugs now helping people to slim down, researchers are working to capitalize on their popularity by bulking up the weight-loss drug pipeline. The latest contender takes a Trojan horse approach — hiding a small molecule in a gut-hormone-mimicking peptide already used in obesity drugs — to strike a double blow to the brain cells that control appetite.
The new work, which demonstrated the effects of this drug candidate in mice and rats, was published today in Nature1.
“It’s a strong paper,” says Daniel Drucker, an endocrinologist at Mount Sinai Hospital in Toronto, Canada, who helped to unravel the role of gut hormones such as GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) in obesity. The blockbuster weight-loss drugs semaglutide (Wegovy) and tirzepatide (Zepbound) act by mimicking these hormones, binding to their receptors on neurons in the brain that control hunger pangs. These drugs can help people to lose 15–20% of their body weight. And it could be possible to eke even more activity from these hormone mimics by fusing them to other drugs, the new study suggests.
“Very high marks for the novelty” of the research, says Drucker, who was not involved and consults for the pharmaceutical industry. “Let’s hope that we’ll see some proof of concept in the clinic”, when the approach is tested in humans.
Trojan therapeutics
The drug contender takes aim at both the GLP-1 receptor and the NMDA receptor, an ion channel found on cells in the brain that was linked to obesity in 20152. At the time, small molecules that blocked the NMDA receptor seemed like a non-starter for obesity-drug developers, because this type of compound, which includes the party drug and antidepressant ketamine, is riddled with harmful side effects.
But Christoffer Clemmensen, a metabolism specialist at the University of Copenhagen, saw a path forwards. He speculated that it might be possible to sidestep the safety risks by fusing an NMDA-receptor blocker to a gut-hormone mimic that acts only on the neurons that regulate appetite.
© 2024 Springer Nature Limited
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