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Newly hatched hummingbird looks, acts like a toxic caterpillar

The white-necked jacobin (Florisuga mellivora) is a jewel-toned hummingbird found in the neotropical lowlands of South America and the Caribbean. It shimmers blue and green in the sunlight as it flits from flower to flower, a tiny spectacle of the rainforest.

Jay Falk, a National Science Foundation postdoctoral fellow at the University of Colorado, Boulder, and the Smithsonian Tropical Research Institute (STRI) in Panama, expected to find something like that when he sought this species out in Panama. What he didn’t expect was a caterpillar in the nest of one of these birds. At least it looked like a caterpillarβ€”it was actually a hatchling with some highly unusual camouflage.

The chick was covered in long, fine feathers similar to the urticating hairs that some caterpillars are covered in. These often toxic barbed hairs deter predators, who can suffer anything from inflammation to nausea and even death if they attack. Falk realized he was witnessing mimicry only seen in one other bird species and never before in hummingbirds. It seemed that the nestlings of this species had evolved a defense: convincing predators they were poisonous.

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Β© Jeff R Clow

We probably inherited our joints from… a fish

What do we have in common with fish, besides being vertebrates? The types of joints we (and most vertebrates) share most likely originated from the same common ancestor. But it’s not a feature that we share with all vertebrates.

Humans, other land vertebrates, and jawed fish have synovial joints. The lubricated cavity within these joints makes them more mobile and stable because it allows for bones or cartilage to slide against each other without friction, which facilitates movement.

The origin of these joints was uncertain. Now, biologist Neelima Sharma of the University of Chicago and her colleagues have taken a look at which fish form this type of joint. Synovial joints are known to be present in jawed but not jawless fish. This left the question of whether they are just a feature of bony skeletons in general or if they are also found in fish with cartilaginous skeletons, such as sharks and skates (there are no land animals with cartilaginous skeletons).

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Β© Rizel_S

Did the snowball Earth give complex life a boost?

Around 700 million years ago, Earth was a frozen, white sphere, its rocky surface buried kilometers under ice. Despite the barren landscape, the evolution of complex life in the oceans was about to pick up steam. New research published this week in Geology suggests that the two realms were more connected than previously thought.

As massive glaciers scratched and scarred Earth’s rocky surface, they freed less-common minerals, which were later flushed into the seas as the ice melted into giant glacial rivers. These minerals in turn may have spurred nutrient cycling in the oceans, boosting the metabolism of microbial life.

β€œIn retrospect, I’m surprised it took [researchers] so long to go and do a study like this,” says Galen Halverson, a stratigrapher at McGill University who was not involved in the work. β€œIt fits with what we understand” about the glaciated Earth.

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Β© MARK GARLICK/SCIENCE PHOTO LIBRARY

Inside the hands-on lab of an experimental archaeologist

Back in 2019, we told you about an intriguing experiment to test a famous anthropological legend about an elderly Inuit man in the 1950s who fashioned a knife out of his own frozen feces. He used it to kill and skin a dog, using its rib cage as a makeshift sled to venture off into the Arctic. Metin Eren, an archaeologist at Kent State University, fashioned rudimentary blades out of his own frozen feces to test whether they could cut through pig hide, muscle, and tendon.

Sadly for the legend, the blades failed every test, but the study was colorful enough to snag Eren an Ig Nobel Prize the following year. And it's just one of the many fascinating projects routinely undertaken in his Experimental Archaeology Laboratory, where he and his team try to reverse-engineer all manner of ancient technologies, whether they involve stone tools, ceramics, metal, butchery, textiles, and so forth.

Eren's lab is quite prolific, publishing 15 to 20 papers a year. β€œThe only thing we’re limited by is time,” he said. Many have colorful or quirky elements and hence tend to garner media attention, but Eren emphasizes that what he does is very much serious science, not entertainment. β€œI think sometimes people look at experimental archaeology and think it’s no different from LARPing,” Eren told Ars. β€œI have nothing against LARPers, but it’s very different. It’s not playtime. It’s hardcore science. Me making a stone tool is no different than a chemist pouring chemicals into a beaker. But that act alone is not the experiment. It might be the flashiest bit, but that's not the experimental process.”

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Β© Jennifer Ouellette

Evolution journal editors resign en masse

Over the holiday weekend, all but one member of the editorial board of Elsevier's Journal of Human Evolution (JHE) resigned "with heartfelt sadness and great regret," according to Retraction Watch, which helpfully provided an online PDF of the editors' full statement. It's the 20th mass resignation from a science journal since 2023 over various points of contention, per Retraction Watch, many in response to controversial changes in the business models used by the scientific publishing industry.

"This has been an exceptionally painful decision for each of us," the board members wrote in their statement. "The editors who have stewarded the journal over the past 38 years have invested immense time and energy in making JHE the leading journal in paleoanthropological research and have remained loyal and committed to the journal and our authors long after their terms ended. The [associate editors] have been equally loyal and committed. We all care deeply about the journal, our discipline, and our academic community; however, we find we can no longer work with Elsevier in good conscience."

The editorial board cited several changes made over the last ten years that it believes are counter to the journal's longstanding editorial principles. These included eliminating support for a copy editor and a special issues editor, leaving it to the editorial board to handle those duties. When the board expressed the need for a copy editor, Elsevier's response, they said, was "to maintain that the editors should not be paying attention to language, grammar, readability, consistency, or accuracy of proper nomenclature or formatting."

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Β© Elsevier

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