2026-08-20の世界

Deep in northern Madagascar, scientists have confirmed that a group of baobab trees long grouped with a well-known species is actually its own distinct kind. A team led by researcher Nisa Karimi at the Missouri Botanical Garden, working with the University of Wisconsin–Madison and Iowa State University, studied detailed genetic data from baobabs growing near the Sambirano River region. The team found that these trees are more closely related to two other northern species, Adansonia perrieri and Adansonia madagascariensis, than to Adansonia za, the species they had been classified under for decades. The researchers revived an old scientific name, Adansonia bozy, first proposed in 1910 by botanists Joseph Jumelle and Henri Perrier de la Bâthie but never formally used until now. The discovery brings the total number of recognized baobab species worldwide to nine, and six of them grow only in Madagascar. Because Adansonia bozy survives in only a small area threatened by deforestation, scientists have preliminarily classified it as critically endangered. Karimi said much of the world's biodiversity remains undiscovered, and sadly, some of it may disappear before researchers even get the chance to study it closely. The findings were published in the journal Taxon.

High in the isolated Baturité Mountains of northeastern Brazil, researchers have identified a new bird species that had been hiding in plain sight for years. Ornithologist Vagner Cavarzere of São Paulo State University, working with colleagues Lucas Romero and Enrico Breviglieri, studied birds long treated as an isolated population of the short-tailed antthrush. The team analyzed 183 audio recordings gathered from citizen science platforms, along with 134 museum specimens and photographs of roughly 80 more birds. Using acoustic analysis combined with machine learning, they found the mountain birds sing an extremely fast, distinctive song, reaching 10.1 notes per second with no overlap with related populations further south. The birds also lack a small black patch above the bill and have a noticeably buffier throat and chest. The researchers named the new species Chamaeza baturitensis, or the Baturité antthrush, after its home range of less than 100 square kilometers. Because the forest patch is so small and faces pressure from poaching, scientists estimate fewer than 100 individuals may remain, and they recommend classifying the species as Data Deficient until more population studies are done. The discovery appeared in the journal Zoologia.

A large Finnish study suggests your daily coffee habit might be connected to more than just an energy boost. Researchers at the University of Oulu, led by doctoral researcher Luca Verroest, examined data from 2,264 people who were all 46 years old and part of the Northern Finland Birth Cohort 1966. The team compared each person's usual coffee intake with their body composition, metabolism, and hormone levels. People who drank more coffee tended to have less total and abdominal fat and more skeletal muscle, even when their body mass index was similar to lighter coffee drinkers. Higher coffee intake was also linked to lower levels of certain amino acids connected to insulin resistance and type 2 diabetes risk in both men and women. Among men specifically, drinking more coffee was associated with healthier blood sugar control and higher testosterone levels. Verroest said coffee is consumed by millions of people every day, yet scientists still know surprisingly little about how it relates to metabolism and hormones. Because the study only shows associations rather than cause and effect, the researchers say more studies are needed before coffee habits can be turned into dietary advice. The findings were published in the European Journal of Nutrition.

A simple choice of words in a nature lesson can change how curious children become about protecting the environment, according to a new Japanese study. Associate Professor Akinori Kitsuki of Kyushu University ran a field experiment in 21 elementary schools in Kushiro City, home to Japan's largest wetland. Students attended the same 45-minute lesson about the local wetland, but the lesson was framed in one of two ways. One version explained the wetland's value to people, such as clean drinking water, flood protection, and recreation. The other version described the wetland's own inner workings, focusing on the interconnections among its plants and animals, apart from any benefit to humans. A week later, only students who heard the human-focused version showed a clear increase in interest in the environment, while the other group showed no measurable change. Interestingly, parents of children in both groups became more interested in the environment after their child attended the class. Kitsuki suggested that a story connected to daily human life may narrow the psychological distance children feel toward nature. He noted the study measured only short-term effects, and added that hands-on fieldwork might help make lessons about nature's own value more effective in the future. The research appeared in the journal Ecological Economics.

Our home galaxy has a hidden chapter in its history, and astronomers have just uncovered it using the Hubble Space Telescope. A team led by Davide Massari at the Bologna Astrophysics and Space Science Observatory in Italy studied 39 globular star clusters within 20,000 light-years of the Milky Way's center. By measuring each cluster's precise age and metal content, the researchers found evidence of a third, previously unknown population of clusters, separate from those born inside our galaxy and those absorbed 10 billion years ago from a dwarf galaxy called Gaia-Sausage-Enceladus. This third group came from an even older collision: about 11.8 billion years ago, when the Milky Way was only about 2 billion years old, it swallowed a smaller galaxy the team named LKH, short for Low-energy-Kraken-Heracles, honoring three earlier studies that had predicted such an early merger. LKH held roughly 500 million times the mass of the sun. Massari said the discovery matters because although the Milky Way is our home, we still do not fully know how our house was built. The findings, published in the journal Nature Astronomy, push back the known history of galactic mergers by 1.8 billion years and show that stars born outside the Milky Way shaped its earliest growth.

A four-thousand-year-old tomb near Luxor, Egypt, gives archaeologists a rare, uninterrupted record of how burial customs quietly changed over seven centuries. Researchers Jared Carballo-Pérez and Miguel Ángel Molinero Polo of the University of La Laguna in Spain studied Chamber 3 inside Theban Tomb 209, part of the Theban Necropolis. The chamber was first used during the 25th Dynasty, around 754 to 656 BCE, and stayed in use until the Ptolemaic period ended around 30 BCE. Inside, the team found 16 mummified people, a mummified dog, and a disturbed deposit holding the remains of at least four more individuals, along with coffins, funerary nets, and amulets. The earliest burials were placed carefully in coffins, suggesting high social status. Over time, bodies were squeezed into whatever space remained, arms shifted from extended to folded, and burials shifted from lying separately to being stacked vertically. By the Ptolemaic period, bodies were mummified without coffins and carefully stacked upright. Carballo-Pérez said the study shows neither chaotic accumulation nor a lost ritual, but rather a spatial logic that adapted to earlier burials. The mummified dog, placed on top of two human mummies, may point to a close bond between people and animals, or a symbolic role guiding the dead into the afterlife. The study appears in the journal Frontiers in Environmental Archaeology.

Later this month, scientists in Germany will melt metal without touching it, using microgravity high above Earth. From August 31 to September 4, a team led by materials scientist Ralf Busch at Saarland University will run experiments aboard the International Space Station, working with the German Aerospace Center, the University of Münster, and the European Space Agency. Inside a device called an electromagnetic levitator, tiny droplets of a nickel-niobium alloy and a nickel-niobium-sulfur alloy will be heated to as much as 1,700 degrees Celsius and held in place by magnetic fields alone, floating freely without touching any container wall. On Earth, gravity forces engineers to use much stronger magnetic fields to hold molten metal in place, and those strong fields create disturbances that make delicate measurements difficult. In microgravity, a far weaker field keeps each droplet stable, letting researchers measure surface tension, viscosity, thermal expansion, supercooling behavior, and heat capacity with much greater precision. Each experiment cycle aboard the station can run for up to 45 minutes, and the team will monitor the glowing droplets live from the German Aerospace Center's control room in Cologne. Before the mission, researchers tested the procedure on parabolic flights that each produced only about 22 seconds of weightlessness. The resulting data should help engineers design tougher, more precise metallic glass alloys for future technology.

Mangrove forests are often described as nature's coastal bodyguards, and new global data suggests they are slowly growing back in many places, even as they vanish in others. Researchers at Aberystwyth University in Wales, led by remote sensing expert Dr. Pete Bunting, built the latest version of Global Mangrove Watch, a tool that uses satellite images and machine learning to track mangrove forests worldwide. Comparing data from 1985 to 2025, the team found that global mangrove cover increased by a net 47,720 hectares over those 40 years. Bunting said the overall increase is encouraging, but progress is far from even across the planet. Indonesia alone has lost 2,044 square kilometers of mangrove forest since 1985, and Myanmar, Malaysia, and Nigeria have also recorded major regional losses even as other areas recovered or expanded. Mangroves protect coastlines from storms and rising seas, support rich biodiversity, sustain local fishing livelihoods, and store far more carbon per hectare than most forests on land. Bunting explained that reliable information about mangroves is essential for understanding what is actually driving these changes, whether restoration projects, natural regrowth, or continued clearing for farming and development. With this new tracking tool, conservation groups and governments can now see, area by area, exactly where mangroves are thriving and where urgent protection is still needed.

Off the coast of Queensland, Australia, scientists just filmed dolphins doing something remarkably clever: hunting fish with seashells. Researchers at the University of the Sunshine Coast, led by animal behaviorist Alexis Levengood, recorded two sightings of wild bottlenose dolphins performing a rare skill called shelling. In shelling, a dolphin chases a fish into a large empty shell, lifts the shell to the surface, and then shakes it so the trapped fish drains straight into its mouth. The behavior was filmed in the Great Sandy Marine Park near Hervey Bay between July and October 2025. Until now, shelling had only been documented in dolphins living in Shark Bay, thousands of kilometers away on the opposite coast of Australia. During one sighting, an adult female dolphin performed the trick while her calf watched closely and then copied the same movements, offering rare evidence that young dolphins may learn shelling by observing their mothers. Levengood said she started screaming with excitement when she realized what she was watching. Local boat operators later shared older photos from 2013 and 2019, suggesting dolphins nearby may have quietly used this hunting trick for more than a decade. The findings, published in the journal Marine Mammal Science, add fresh evidence that dolphins are capable of impressive tool use and cultural learning.

Scientists have pulled a 2,000-year story of Earth's atmosphere out of ice on the world's highest tropical mountain. Researchers at Ohio State University's Byrd Polar and Climate Research Center drilled ice cores from the summit of Nevado Huascarán in Peru, nearly 7,000 meters above sea level. Trapped inside the ice were tiny air bubbles that had been sealed away for centuries, preserving a detailed record of atmospheric methane, a powerful greenhouse gas. Lead researcher Kara Lamantia said Huascarán is a Goldilocks spot for capturing global methane, because its high elevation and location near the equator let it record signals from both hemispheres. The team found that methane levels in the tropical ice broadly matched patterns already known from polar ice cores, but were consistently a little higher. That difference supports a long-standing idea that the Amazon rainforest and other tropical wetlands were the planet's dominant natural methane source before the Industrial Revolution. After industrialization, farming and fossil fuel use pushed methane levels even higher worldwide. The study, published in the journal Nature, gives scientists their first global, tropical-inclusive record of preindustrial methane, filling a major gap left by ice cores collected only near the poles. It offers a clearer baseline for understanding how much methane humans have added to the atmosphere since.

Have you ever wondered exactly how your brain knows you have stayed awake too long? Researchers at the Biozentrum, University of Basel, in Switzerland, say they have found part of the answer inside the brains of mice. Led by Professor Alex Schier, the team worked with scientists from Beth Israel Deaconess Medical Center and Auburn University to study neurons that switch on during long periods of wakefulness. Using detailed brain mapping, targeted genetic tools, and recordings of brain activity, they identified two groups of wake-activated neurons that appear crucial for sleep drive, the growing pressure to sleep that builds the longer an animal stays awake. When the researchers artificially activated these neurons, the mice slept longer and more deeply, showing the kind of recovery sleep that normally follows sleep deprivation. When the team instead switched the neurons off for a longer period, the mice needed roughly 70% less sleep than usual and still stayed alert. Schier said the neurons do not simply signal that an animal has been awake; instead, his experiments show they actively promote sleep and may be key parts of the circuitry that generates sleep drive itself. The study, published in the journal Nature, offers one of the clearest pictures yet of how the brain converts hours of wakefulness into an urgent need to rest.

Scientists in Germany have built robots so small that 50 of them could fit across the width of a single human hair, and these tiny machines can already hunt down bacteria on their own. A team led by Professor Bert Hecht at Julius-Maximilians-Universität Würzburg created the light-driven nanorobots, which measure less than one micrometer across. Instead of using batteries or motors, each robot carries up to four plasmonic nanoantennas that absorb light and re-emit it in the opposite direction. Every redirected photon produces a tiny recoil force, similar to the kick of a fired gun, and that force is strong enough to push and steer the robot through liquid. By simply changing the polarization of the light shining on them, researchers can steer the robots with precision, sending them to chase down individual bacteria, capture them, and carry them to a chosen location. Lead experimental scientist Jin Qin said the team had essentially built a light-driven nanorobot that can track down and collect bacteria. The robots stay maneuverable even while carrying bacteria, although they move more slowly under a heavier load. The research, published in the journal Nature Communications, suggests these microscopic cleaners could someday help scientists study microbes, develop new medical treatments, or rearrange materials on a scale invisible to the naked eye.