While carbonaceous chondrites make up only a small portion of the meteorites sampled on Earth, CO chondrites make up a very tiny fraction of those meteorites. According to the study, these types of meteorites are among the most pristine materials in our Solar System.

According to the study, the Cretaceous-Paleogene impactor was about six to nine miles wide and created a massive crater in the Yucatán Peninsula in Mexico. It was eventually named the Chicxulub crater.

“Being impacted by such a rare, distant projectile really underscores how unlucky the dinosaurs were,” Claeys said.

cross-posted from: https://hexbear.net/post/8995304

Banner image: Dorymyrmex ants clean workers of a different ant species. Image by Moffet, 2026 (CC BY 4.0).

Unusual ant interaction hints at mutualistic ‘cleaning’ system

Some coral reef ecosystems famously have “cleaning stations,” where fish line up to be cleaned by other species of fish and shrimp. Entomologist Mark Moffet recently published observations of what appears to be a similar relationship in ants.

In the Chiricahua Mountains of the U.S. state of Arizona, Moffet, from the National Museum of Natural History, was watching harvester ants (Pogonomyrmex barbatus) collecting seeds when he noticed something odd. He saw several harvester ant workers frozen in place. When he zoomed in with his camera, Moffet saw the harvester ants covered with cone ants (Dorymyrmex spp.).

At first Moffet assumed he was seeing aggression between the species. On closer inspection however, he observed that the small cone ants were licking and nibbling the larger harvester ant workers, not fighting with them. Moffet observed the cone ants inspecting the harvester ants’ open mandibles, which could easily crush the smaller cone ants.

Moffet observed at least 90 individual harvester ant workers being tended this way and concluded that they might be getting cleaned by the cone ants. He even watched harvester ants approach the nests of cone ants and wait for cone ants to attend to them, which reminded him of reef fish lining up for a cleaning by cleaner fish species.

The big question is: What is each species getting out of the arrangement? Moffet consulted colleagues and came up with several possible explanations. Perhaps the ants exchange microbes, which create a healthier microbiome for both species. Or maybe they swap pheromones, to keep harvester ants from attacking cone ants later on. Maybe the cone ants impart an antifungal substance they’re known to produce.

Another possibility is that the cone ants get a free meal. “The Pogonomyrmex are called ‘harvester ants’ because they harvest seeds and store them in underground larders,” Moffet told Mongabay by email. “Seeds are high in calories and a carbohydrate-rich dust from them are likely all over the ant’s body surfaces — an energy rich snack that would be invisible to the eye.”

In return for that snack, the cone ants may be helping the harvester ants stay free from disease by eating seed dust that could potentially contain harmful microbes.

The cleaner ant system might be an example of mutualism — a symbiotic relationship that benefits both species — but this hypothesis needs more research. “I want to go back and take a further look. But proving that this is a mutualism would take quite a bit of time — what we need is an interested PhD student!” Moffet wrote.

Daniel Kronauer, an ant biologist at Rockefeller University in the U.S., who wasn’t involved with the cleaner ant research, told The New York Times that “It’s a pretty unique observation” that could lead to new directions in research.

cross-posted from: https://hexbear.net/post/8987286

Why these toads are evolving faster than anyone expected

An invasive cane toad (Rhinella marina) is measured in Australia. (Chris Barlow / Macquarie University via SWNS)

By Stephen Beech

Cane toads have leapt ahead of evolution theories by growing bigger and changing more rapidly than expected, according to new research.

The invasive species has bulged in size since being introduced into Japan less than 50 years ago, reveals the study.

Scientists say their findings suggest environmental pressures can drive rapid biological change.

The study comparing invasive cane toads in Japan and Australia found "substantial" changes in body size and shape have developed much more rapidly than suggested by long-held ideas of the pace of evolution.

Researchers measured and weighed wild-caught cane toads on Ishigaki Island in southern Japan and compared them to toads measured in Australia, Hawaii and South America.

A large cane toad outside. (Photo by Flávio Santos via Pexels)

The most striking difference was in body size with adult toads from Ishigaki weighing an average 190 grams (0.4 lbs) compared to 135g (0.3 lbs) for toads from Australia, while their average length was 122 millimeters (4.8 inches) compared to 111mm (4.3 ins).

The findings, published in the journal Royal Society Open Science, also showed that Ishigaki toads had wider heads, shorter arms and longer legs than toads from other locations.

Cane toads have spread to more than 40 countries worldwide from their ancestral habitat in north-eastern South America.

They first spread to Puerto Rico and then to Hawaii and from there to Australia in the 1930s.

The toads of Ishigaki were introduced from Hawaii, via Taiwan and the Daito Islands, in 1978.

Senior researcher Rick Shine said: "Given these populations of toads in Japan and Australia shared a common history in Hawaii until the 1930s, these differences in size and body shape have developed in less than 100 years.

"The idea that evolutionary change happens at a glacially slow pace is being challenged by recent evidence showing rapid changes in species confronted with novel challenges, like being translocated to a different habitat."

The study didn't collect sufficient data to allow researchers — from Macquarie University and the University of Sydney in Australia plus Kyoto University in Japan — to test alternative theories about what might be driving the changes in body size.

But the research team speculated that the larger body sizes of Ishigaki toads could reflect favorable climatic conditions, particularly year-round rainfall or the impact of lower pressure from predators on the island.

Shine, an evolutionary biologist and ecologist at Macquarie University in Sydney, added: "We don't have a clear idea of the evolutionary forces that might be involved, so we can't say why body mass and shape has changed among the toads in the Japanese system."

cross-posted from: https://lemmy.world/post/49405375

Science as a human right: call for ISC Member endorsement

@science

https://council.science/news/science-human-right-isc-member-endorsement/?utm%5C_source=rss&utm%5C_medium=rss&utm%5C_campaign=science-human-right-isc-member-endorsement

cross-posted from: https://hexbear.net/post/8969839

Some rays flash decoy eyes while others never do, as evolution's hidden trade-off comes into focus

Pacific Starry Skate. Credit: Andy Murch.

From butterflies to peacocks, bold circular "eyespots" are among nature's most eye-catching patterns. But why do they appear in some animals and not others? A new study of skates and rays finally provides an answer—and it lies in the full range of defenses an animal has at its disposal.

In a study examining more than 580 species—over 90% of all known skates and rays—researchers from Stockholm University have mapped the evolutionary history of conspicuous markings across this ancient group of cartilaginous fishes.

By analyzing multiple anti-predator defenses together, rather than studying eyespots in isolation, they were able to explain why such dramatic visual signals appear in some groups but are completely absent in others. The work has been published in Nature Ecology & Evolution.

"Our results show that you have to look at the full range of options for avoiding predators. Eyespots evolve only under certain ecological and defensive conditions. They are one solution among many in the evolutionary arms race between predator and prey," says lead author Madicken Åkerman.

Mediterranean Rough Skate. Credit: Andy Murch

Rasptail Skate. Credit: Andy Murch.

Different species, different toolkits

Skates and rays face a wide range of predators, including sharks, marine mammals and large fish. Some species defend themselves with powerful electric organs or venomous spines. Others rely more heavily on camouflage, burying themselves in sand on the ocean floor.

The researchers found that species equipped with such robust defenses rarely evolved conspicuous markings. In contrast, smaller-bodied species without those weapons were much more likely to develop bold spots or eyespots—particularly if they lived in well-lit, shallow waters less than 200 meters deep.

"Eyespots are far from random. They tend to evolve in species that lack strong physical defenses, such as venomous tail stings or electric shocks, and that live in bright, shallow waters where visual signals are effective," says senior author John Fitzpatrick.

John Fitzpatrick at Stockholm University. Credit: Anette Gärdeklint Sylla/Stockholm University

"Evolution seems to favor different defensive toolkits. If you already have a strong mechanical or electrical defense, you don't also need a visual warning signal," says Madicken Åkerman.

A stepwise process

The study also uncovered a surprising evolutionary pattern: eyespots almost never evolved directly. Instead, species typically first gained simpler markings—such as bold spots—which were later refined into the classic concentric-ring eyespots seen in some skates. In evolutionary terms, gaining simple markings was about 100 times more likely than gaining eyespots outright.

"It appears to be a stepwise process. Other markings come first, and over time they refine into eyespots," says John Fitzpatrick.

Yet conspicuous markings are also frequently lost. This makes sense when considering the trade-off at play. In deep, dark waters where little light penetrates, a visual signal cannot be seen—and therefore offers no protection. Under those conditions, the cost of being conspicuous outweighs the benefit—and the markings disappear.

cross-posted from: https://hexbear.net/post/8953267

Banner image: Lilac-breasted roller in Etosha National Park, Namibia. Image courtesy of Giles Laurent via Wikimedia Commons, CC BY-SA 4.0.

How Namibia's bird conservation projects build community resilience (commentary)

• Droughts and land degradation often erode communities’ social bonds, but in the Karas region of Namibia, bird conservation initiatives have become a rallying point.
• Women and youth are at the forefront of these initiatives, which has inspired confidence among peers and shown that conservation is not the domain of scientists alone, but also a practice of everyday community resilience.
• “It is time for policymakers, NGOs, and donors to support these initiatives not just as biodiversity projects, but as investments in community well-being,” a new op-ed argues.
• This article is a commentary. The views expressed are those of the author, not necessarily of Mongabay.

In Namibia’s Karas Region, birds are more than symbols of freedom or beauty — they are teachers of resilience. Their survival in arid landscapes mirrors the endurance of the communities who live alongside them. Grassroots bird conservation projects here have revealed something profound: protecting birds can also strengthen families, nurture hope, and build social cohesion.

Across villages in Karas, parents and children tend habitats together, restoring nesting sites and planting native vegetation. These acts of care are not only ecological interventions; they are lessons in patience and problem solving. When a child sees a weaverbird return to a reed bed that the community has protected, it is a moment of triumph that teaches perseverance in the face of environmental challenges.

Women and youth are at the forefront of these initiatives. In one community, a group of young women organized bird walks for schoolchildren, teaching them to identify species like the sociable weaver and the pale chanting goshawk. Their leadership has inspired confidence among peers and shown that conservation is not the domain of scientists alone — it is a practice of everyday resilience.

Sociable weavers nesting in acacia trees, Karas Region, Namibia. Image courtesy of Martha Karas.

These projects also counter the isolation that environmental stress can bring. Droughts and land degradation often erode social bonds, but bird conservation has become a rallying point. Families gather to monitor nesting sites, share stories, and celebrate small victories. In doing so, they weave resilience into the social fabric. Conservation here is not only about biodiversity; it is about belonging.

The ecological benefits are clear. Protecting bird habitats safeguards pollination, seed dispersal, and pest control — services that sustain agriculture and livelihoods. But equally important is the emotional strength these projects cultivate. In Karas, conservation has become a human resilience strategy: a way to confront uncertainty with collective action and hope.

This perspective challenges the conventional view of conservation as a technical exercise. Too often, policies focus narrowly on species counts or protected areas. While these metrics matter, they overlook the lived experience of communities who find strength in caring for nature. By recognizing conservation as both ecological and social, we broaden its value and deepen its impact.

Lappet-faced vultures like this are native to the arid plains of the Karas Region, and organizations like Vultures Namibia ensure there’s awareness of them. Image courtesy of Martha Karas.

The lesson from Karas is urgent. As climate change intensifies, resilience will be as critical as resources. Grassroots bird projects show that resilience can be cultivated through simple, shared acts of care. They remind us that conservation is not only about saving species, but about sustaining the human spirit.

It is time for policymakers, NGOs, and donors to support these initiatives not just as biodiversity projects, but as investments in community well-being. Funding should prioritize programs that empower women and youth, foster intergenerational learning, and strengthen social bonds through conservation.

Birds in Namibia’s Karas Region are survivors of harsh landscapes. But they are also mentors of resilience, teaching us how to endure, adapt, and thrive together. By listening to the voices of those who lead grassroots efforts, we can reimagine conservation as a strategy for human strength as much as ecological survival.

Supporting these projects is not charity — it is foresight. In every nest protected, in every child inspired, we see the seeds of resilience that will carry communities through the challenges ahead.

Conservation, at its best, is a story of hope. And in Karas, that story is being written by birds and the people who care for them.

Martha Karas is a Namibian writer based in the Karas region.

cross-posted from: https://hexbear.net/post/8933482

If you are ever confronted by a toad, you soon see why there is little chance of confusing it with its froggy cousin.

I realised this after discovering a glorious, warty specimen settled on damp concrete in the garage one autumn. It was not only its copper-coloured eyes, squat boxer face and bumpy, waterproof skin — allowing it to survive away from water for longer — but its size that impressed. Wild toads can live for more than a decade; this creature may have been as old as my son.

After some deliberation (and Googling) I moved my toad to a pile of logs and fallen leaves near the pond. It was silent as I transported it, in gloved hands to protect its skin from mine, which meant it must have been a female: only male toads squeak when picked up.

Sadly, a report recently found that the chance to perform a toad relocation may become rarer than ever. Led by Dr Silviu Petrovan of the University of Cambridge in collaboration with the charity Froglife last October, it used one of the biggest data-sets ever gathered for amphibian population trends; between 1986 and 2021, a dedicated team of volunteers counted migrating toads during the spring breeding season. The findings were sobering: over the past 40 years, the UK population has declined by nearly half. The common toad (Bufu bufo), now reassessed as ‘near threatened’ in England and Scotland, may soon need a new name.

'In 2025, 275 active patrols helped almost 135,000 toads complete their lust-driven journey to reproduce'

(Image credit: Getty Images/Westend61)

One of two species native to Britain, the common toad has a place in our culture not enjoyed by the natterjack, whose home on sandy coasts and modest population has meant few of us will ever encounter one. The common toad, however, has had a near-ubiquitous presence in Britain since the last Ice Age: a study of frog and toad bones at Repton in Derbyshire found evidence of local populations as far back as the 8th century. The excavation concluded there was a toad boom in the 14th century, which might explain why the creature begins then to creep from folklore into literature.

From magic and medicine to myth, toads have been linked always to the suspicious and powerful: a toad is the first ingredient Shakespeare’s witches drop into their cauldron in Macbeth, the 15th-century Scottish poet Robert Henryson makes his toad treacherous and Milton’s Paradise Lost has Satan himself choosing to inhabit one for his disguise.

As with all folklore, there is confusion: what is bad is also powerful and power is something people try to harness. Across medieval Europe, women were advised that a toad effigy clamped between the knees during childbirth could ease labour pains. Meanwhile, toads were thought to carry a jewel in their heads that changed colour to warn of poison and protect against evil — or, as Shakespeare wrote in As You Like It, the toad was ‘ugly and venomous, wears yet a precious jewel in his head’.

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These ‘toad-stones’, mentioned since the Middle Ages, became especially popular between the 14th and 17th centuries. They were, in fact, often fossilised fish teeth, but that did not stop people believing the proper way to extract one was to sit a toad on a red cloth until it belched the stone up, to be caught and set into a ring or amulet for luck.

'Frequently one comes upon shapeless masses of 10 or 20 toads rolling over and over, one clinging to another without distinction of sex'

Two toads, inspiring enough for George Orwell.

(Image credit: Getty Images/Stephan Gehrlein/500px)

Modern literature has given the poor old toad a gentler reputation. In his superb 1946 essay Some Thoughts on the Common Toad, George Orwell describes the creature after hibernation as having ‘a very spiritual look, like a strict Anglo-Catholic towards the end of Lent’. The essay credits the toad — not the cuckoo — as the herald of spring. His description of toad copulation brings to mind a particularly lively urban Saturday night, with the creature entering ‘a phase of intense sexiness. All he knows, at least if he is a male toad, is that he wants to get his arms round something and if you offer him a stick, or even your finger, he will cling to it with surprising strength and take a long time to discover that it is not a female toad. Frequently one comes upon shapeless masses of 10 or 20 toads rolling over and over, one clinging to another without distinction of sex’.

My own re-homed toad did not hop into her new refuge, but crawled, stretching her limbs across the leaves like an aged yogi. The glands in her bumpy skin contain toxins that deter predators, meaning that, unlike the frog, she can stroll away from trouble rather than leap. I never saw her again, nor any sign of the alien-like double-rowed strings of eggs she might have left clinging in the pond. Around St Valentine’s Day, amorous toads leave hibernation and begin their migration to ancestral breeding ponds, sometimes many hundreds of feet away. Most return to the very pond of their birth, using chemical signals and magnetic orientation to find their way — regardless of whether a new A-road now crosses their route. The long, jelly-like strings of eggs hatch within days. It takes two or three months for a tadpole to become an inch-long toadlet, which must then brave cars and predators as it leaves the water to find new ground for feeding and hibernation.

Toads return to the same ponds, which means when those ponds are drained or built over it breaks a link that is both ancient and ecological. Although a toad’s skin may look tough enough for a witch’s cauldron, it is porous. Agricultural pesticides seep through it, poisoning the animal, at the same time as killing off its food sources, such as spiders, beetles, worms and slugs. The creatures that prey on pesticide-poisoned toads are also affected, hedgehogs and otters among them, which often skin the toad inside out to avoid its toxic glands. Climate change, too, plays its part. Last year saw the driest spring in more than a century, disrupting hibernation and the availability of a toad’s choice of food, and milder winters cause toads to wake too soon, losing body condition and producing fewer eggs.

Why should we care about the much-maligned toad, apart from the fact that a world with one hiding in your garage is richer than a world without? The answer lies in the natural cycle. As with birds and insects, the decline of once-common species sends ripples along the food chain. As Froglife’s report notes: ‘It is not extinction, but the population decline of abundant species that will have the most serious ecological consequences. Abundant species tether food webs, account for much of the interaction diversity in a given community, and carry out ecosystem services’.

There is some good news. Froglife reports that, although toad populations crashed by 68% per cent between 1985 and 2013, efforts in the past eight years have brought ‘regional recoveries’, reducing the total decline to under half. Much of this is thanks to the Toad Patrols — volunteers who literally carry toads across roads by the bucketful. In 2025, 275 active patrols helped almost 135,000 toads complete their lust-driven journey to reproduce.

'It would be a shameful thing to have created a landscape that in only 40 years manages to kill off a creature that has survived 400 million, through the extinction of the dinosaurs to the Industrial Revolution'

It takes two or three months for a tadpole to become an inch-long toadlet, which must then brave cars and predators as it leaves the water to find new ground for feeding and hibernation.

(Image credit: Getty Images/Naturfoto Honal)

Community-led action can sound worthy, but futile. In fact, there is precedent in the revival of another creature once commonly squashed on tarmac: the hedgehog. As rural populations continue to fall, urban hedgehogs are making a comeback. The excellently named HogWatch project has seen dramatic rises in hedgehog populations in Highgate Wood, north London, in only eight years, thanks solely to citizen action. In October 2024, the National Hedgehog Conservation Strategy—launched by the People’s Trust for Endangered Species and the British Hedgehog Preservation Society — became the world’s first of its kind, providing a frame-work for NGOs, government, landowners and communities. The Hedgehog Street campaign has already recruited more than 100,000 ‘hedgehog champions’.

Are toads the new hedgehogs? Let’s hope so. It would be a shameful thing to have created a landscape that in only 40 years manages to kill off a creature that has survived 400 million, through the extinction of the dinosaurs to the Industrial Revolution.

In the meantime, anyone with a garden can help. Despite not being able to build amphibian tunnels for commuting juveniles, Jenny Tse-Leon, head of conservation and Impact at Froglife, says that ‘the restoration and creation of more and better-connected ponds and habitats such as woodlands and grasslands are essential to their survival’. No matter the size of your garden, a small pond, log pile, stones or even an upturned flowerpot can become a summer refuge and a winter hibernaculum.

One day, perhaps, the sight of a toad making its slow, dignified way through the garden may become as common as it once was — and our children, too, might move one from a garage to a bed of leaves and see for themselves why these characterful creatures have long been woven into the fabric of British culture.