Creatures that bridged the gap between reptiles and mammals may have been bearing live young 90 million years earlier than we thought.

One of the hallmarks of all mammals apart from monotremes – echidnas and the platypus – is that they give birth to live young. This “viviparity” contrasts with the “oviparity” seen most other vertebrates, in which females lay eggs that hatch outside their bodies.

One long-standing question has been whether creatures known as cynodonts, which emerged around 260 million years ago during the Permian geological period and are directly ancestral to all mammals, laid eggs or gave birth to live young, as no evidence of their reproduction has been discovered either way.

“Whether mammalian ancestors were oviparous or viviparous has been considered a mystery,” says  at Argentina’s National Scientific and Technical Research Council. “We had no clues on how or when one of the most distinctive traits of the majority of present-day mammals, viviparity, evolved in the mammalian lineage.”

This has now changed, thanks to a chance observation made during a postgraduate class at the University of Buenos Aires in Argentina. The students were examining a fossil of Chiniquodon theotonicus, a cynodont that lived 236 million years ago and was unearthed in the Talampaya National Park in north-western Argentina in 2011. Part of the analysis involved using a microscope to examine thin slices taken from one of the ancient animal’s leg bones. At that point, the class noticed a curious growth line inside the bone.

Gaetano and his colleagues investigated further and eventually concluded that this line, analogous to a tree’s growth ring, recorded the moment that the ancient mammal relative went through a growth spurt after its birth.��

The researchers reconstructed how large the leg bone and the animal itself would have been when the growth line formed. They calculated that the animal would have weighed 1.68 kilograms at that point. When the animal died as a full-grown adult, it was just shy of 12 kilograms.

This gave the researchers a ratio of newborn to adult size in the ancient animal. They then compared this figure to similar ratios obtained from a wide variety of modern animals: 1869 mammals, 2619 non-avian reptiles and 782 birds.

“We were amazed to find that ��󾱲Ծ���ܴǻ�Dz���grouped with extant placental mammals,” says Gaetano.

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Egg-laying animal groups produce young that are far smaller than adults when they hatch, he says.

For example, some species of large birds have newly hatched young that are just 0.002 per cent of adult body mass, whereas placental mammals often give birth to young that are over 20 per cent of the size of their parents.

“Only placental mammals produce relatively large newborns, whereas reptile and bird hatchlings are comparatively very small,” says Gaetano. “Hence, we propose that [the] Chiniquodon theotonicus reproductive strategy was most similar to that of placental mammals.”

 at the University of Bristol in the UK says the findings are convincing.

“Further, as they argue, the apparent absence or rarity of actual eggs of any kind in the Permian and Triassic has always been puzzling – the so-called amniote egg gap,” he says.

 at Macquarie University in Sydney says his gut reaction is to be sceptical of the claim of live birth, as we have only indirect evidence. But he is impressed that, in the absence of any direct fossil evidence, the team is still trying to solve the puzzle.

“We may never get any of the kind of direct evidence that solves the
mystery, for example a fossilised mammalian egg or a fossil mother during
pregnancy,” he says. “So it is kind of cool that they’re taking a different approach to trying to find an answer to that question.”

Two beagles called Alfie and Bailey lack the main protein that causes allergic reactions to dogs, thanks to CRISPR gene editing. The dogs will be 2 years old in September and show no signs of adverse effects, according to , the company behind them.

“I’ve lived with allergies my whole life. They prevented me and my family from ever having a dog,” says Kindred co-founder Matt Walker. “And my wife, Maggie, has always wanted a dog.” Walker previously worked as a researcher studying neuron development in worms by using CRISPR gene editing to disable specific genes. He realised it might be possible to use the technique to prevent dogs causing allergies, and founded Kindred in 2020.

How were Alfie and Bailey created?

Previous studies have found that the main allergen that triggers reactions to dogs is a protein called Can f 1. It is secreted by the tongue and by glands in the skin, so it is present both in the fur of dogs and in their saliva.

The Kindred team took skin cells from a female beagle and used the gene-editing tool CRISPR Cas9 to mutate the Can f 1 gene – the result was an extra DNA letter at the start of the gene that shifts the way the recipe for making the Can f 1 protein is read by cells, turning it into gibberish. Once the team members had confirmed they had made the desired change without introducing unwanted mutations, they cloned the cells. Altogether, the team transferred 25 embryos to a surrogate, of which two implanted and developed to term.

Does removing this protein really prevent allergies?

Bailey is Walker’s pet dog, and he says he has no reaction to her at all. She was cavorting in the background when New Scientist spoke to him. Kindred has also showing that Can f 1 is undetectable in Alfie and Bailey, and that there are no allergic reactions to samples from them in skin-prick tests, whereas samples from normal dogs do provoke a reaction.

However, Can f 1 isn’t the only protein in dogs that can trigger allergic reactions – there are also so-called minor allergens, such as Can f 2. “If we do find that there’s a substantial population that is still responding to the dogs, then that is something we could address,” says Walker.

And could the process be harmful to dogs?

We don’t know for sure what the function of Can f 1 is, but Walker says he was confident from experiments on mice that there would be no serious consequences from deleting it. So far, both dogs appear normal and healthy, he says. “Of course, that’s something that we’re monitoring very closely, and will continue to monitor over the animals’ lives.”

Isn’t it already possible to buy “hypoallergenic” dogs?

Some breeds, such as poodles and goldendoodles, are said to be less likely to trigger allergic reactions, but Walker says he responds just as much to the goldendoodle his parents bought after he left home as he does to any other dog. In the paper, his team shows that Can f 1 is detectable in both breeds, and that samples from them trigger reactions in skin-prick tests.

This is in line with independent evidence. The American Academy of Asthma, Allergy and Immunology says some “hypoallergenic” breeds .��

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When will these dogs be commercially available?

Not for some time. Kindred first needs regulatory approval from the US Food and Drug Administration. If it gets that, it then needs to create lots more of these dogs. For each dog breed, the company will have to create a genetically diverse set of “founder” dogs that can then be bred normally. Walker couldn’t say how many founder dogs would be required per breed.

Is it ethical to genetically engineer dogs just to prevent allergies?

“We aren’t using gene editing for novelty or some cosmetic reason,” says Walker. “Allergies are a real health problem. They affect a significant portion of the population, and lead to serious conditions such as asthma triggering asthmatic attacks.”

By contrast, conventional dog breeding is often done purely for the sake of appearance, and can introduce mutations that cause serious harm, such as those found in breeds like pugs .��Nevertheless, Kindred is altering dogs for the benefit of humans rather than the benefit of the animals themselves. In response to this, Walker says people discovering they are allergic to dogs is a leading reason for animals having to be rehomed.��

Is Kindred planning to gene-edit cats, too, to prevent allergies?

“Right now, we’re focused exclusively on dogs,” Walker says. The main allergen in cats, called fel d 1, is encoded by two genes rather than one, so getting rid of the protein is more complex. Another company called InBio announced plans to create cats free of fel d 1 in 2022.

Large predators can make people safer by reducing the number of road accidents involving collisions with deer. A study in Washington state has shown that the presence of cougars led to a 76 per cent reduction in the number of such accidents.

“I think that this road-safety benefit could be playing out in many other places,” says of the non-profit Conservation Science Partners. “That’s just one of several ecosystem services that these large carnivores provide.”

A 2021 study in Wisconsin found that the return of wolves to a county , providing economic benefits 63 times greater than the costs of wolves killing livestock. These reductions were due to changes in deer behaviour, as well as deer numbers falling due to predation by wolves, the study concluded.

Now Suraci and his colleagues have looked at what’s happening on the Olympic Peninsula in Washington state, where there’s a stable population of cougars – also known as pumas – and deer. “We worked with Native American communities, who are running their own wildlife monitoring programs,” he says.

More than 500 camera traps have been set up as part of these programs, and nearly 60 cougars were collared. This allowed the researchers to see where and when deer and cougars were present. Their analysis shows that deer avoid road edges and the margins of towns and cities when cougars are present, making them less likely to be hit by cars or trucks.

“Those habitat edges are the best hunting habitat for pumas. They can hide in the forest and attack a deer foraging along the roadside,” says Suraci. “So what we think is happening is that deer are moving away from these more fragmented, edgy areas with higher road density where the pumas are present.”

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When cougars were present, deer were also less active at night and more active during the day. This is likely a response to the fact that cougars hunt mainly at night, and may also have contributed to the reduction in accidents.

This is an example of a “landscape of fear” in action, says at Western University in Canada. “This is an excellent paper. It provides many compelling lines of evidence that paint a clear picture – that large carnivores benefit society. The authors beautifully demonstrate that the mere presence of large carnivores can reduce vehicle collisions with deer.”

“That is good news all around,” she says. “As though that weren’t enough, cougars also provide this service completely free of charge.”

Suraci also thinks this will be generally true for large predators. Discussions about the reintroduction of large predators tend to focus on the negative aspects, such as the killing of livestock, he says. But many benefits often aren’t obvious.

For instance, large predators may also reduce the damage deer do to crops and gardens, and the spread of diseases .

Don’t treat your pets for parasites such as ticks and fleas unless they actually need treating. We can’t be sure that these treatments are safe for you and your family, and there is growing evidence that they pose a danger to wildlife.

So says a by the Environment and Climate Change Committee of the UK’s House of Lords. It is calling for the sale of these treatments to be restricted, so people can only buy them after consultation with a vet, pharmacist or qualified pet shop staff.

The main issue is that there is no rigorous assessment of pet treatments before they are approved, the report says. It has simply been assumed by national and international regulators that they are safe, but this assumption is turning out to be wrong.

In particular, at least two potent pesticides found in tick and flea treatments are getting into UK rivers at levels high enough to affect wildlife. These pesticides can break down into other substances that are even more harmful.

“There is also worryingly insufficient evidence to assess whether or not [pet parasite medicines] are harmful to human health,” says the report.

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It also says regulators aren’t sufficiently independent. Both UK and international regulators “appear to be too influenced by and beholden to the views of the industry”, it states.

While the report focuses on the UK, the same tick and flea treatments are sold in many countries. “This is a worldwide issue,” says at Imperial College London, one of the experts who gave evidence to the committee.

“There’s been a historical assumption that any veterinary medicine used in non-food animals – cats and dogs, companion animals – is associated with negligible environmental risk,” she says. “Effectively, they have no meaningful environmental risk assessment.”

But recent research shows they do pose a risk, says Perkins. “It’s really opened up a Pandora’s box, because we have dozens of these products that have been approved based on this assumption that we now know is not scientifically valid.”

For instance, two common pesticides found in products such as spot-on flea treatments are fipronil, a broad-spectrum insecticide, and imidacloprid, a neonicotinoid. “They’re incredibly potent at extremely low levels,” says Perkins.

Both pesticides used to be used on farms until they were banned a few years ago. But they have continued to be found in rivers. In fact, with the development of more sensitive tests, they are turning up “pretty much everywhere in waterways”, says Perkins.

Initially, it was thought this was a legacy of their use by farmers, but work by Perkins and others suggests parasite medications are now the main source of these pesticides in waterways. In many cases, levels are high enough to harm invertebrates such as mayflies, dragonflies and caddisflies, with knock-on effects on the fish and birds that feed on them.

We don’t know how big a problem this is, says the report. “The true scale of environmental harm resulting from pet parasite medications is not known.”

How are the pesticides getting into rivers? Once they are applied to pets, they end up all over the home, says Perkins. When people bathe their pets or wash pet bedding, they can end up in wastewater.

Product packaging currently recommends that dogs are not bathed for four days after treatment, but this needs to be extended to 28 days, the report recommends.

Another major source of the pesticides in water is hand-washing, says Perkins. “We detected [pesticides] in the wash-off even before we asked people to stroke their pets, so they’re just constantly on the hands of pet owners.”

Products containing fipronil and imidacloprid are now being replaced by ones containing isoxazolines, typically sold in the form of chewable tablets. Isoxazolines are less water-soluble but can bind to sediments and accumulate in soils and sewage sludge. They might be ending up in fields when sewage sludge is sprayed as fertiliser and harming pollinators.

“There has not been much work done to date to assess this,” says the report.

Shed dog fur is yet another way these chemicals can end up in the environment. The report says contaminated fur has been found in bird nests.

In light of these findings, the use of pet parasite medications should be minimised until there is independent research clarifying their risks, says the report. At present, manufacturers of parasite treatments are promoting the idea that routine treatment for parasites is required, and encouraging pet owners to get them via monthly subscriptions. “However, the benefits of routine, and certainly monthly, pet parasite medicine usage are not supported by scientific evidence.”

It is an excellent report, says Perkins, but she hoped it would go further and recommend making these products prescription-only. Some wildlife groups, meanwhile, want .

Yet another reason for restricting their use is to slow the development of resistance, says Perkins. She sees a lot of animals treated with old spot-on treatments containing fipronil that still have fleas. “We need effective parasite treatments, and we need to make sure we preserve their efficacy,” she says.

More than 150 years after Charles Darwin proposed that saxifrages were a group of plants that practiced carnivory, researchers have meticulously gathered the evidence to confirm he was right.

“Talk about an amazing feeling,” says at the University of Florida. “To have the opportunity to confirm a prediction of Darwin is both humbling and very exciting.

“I would like to think Darwin would be pleased [and say] ‘I was right – again.’”

To formally qualify as a carnivorous plant, a species must possess adaptations that enable it to attract, capture and digest its prey and absorb nutrients from it. Perhaps the world’s most renowned carnivorous plant is the Venus flytrap (Dionaea muscipula).

In 1875, four years after detailing his theory of natural selection in his book On the Origin of Species, Darwin wrote about in the genus Saxifraga, which were known to catch insects.

The genus has around 450 species and is found in Arctic and alpine regions of the northern hemisphere as well as in the South American Andes.

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However, despite attempting several experiments to prove the plants digested the insects, Darwin was unable to substantiate his hunch.

To take up the challenge, Soltis and his colleagues studied specimens of Saxifraga candelabrum from Wufeng Mountain in Yunnan province, China – a different species from those studied by Darwin, but in the same genus.

During field surveys, the botanists observed that the Saxifraga candelabrum plants were capable of trapping small insects, using hairs covered with a sticky secretion. Bigger insects – those more useful to the plants for pollination – weren’t captured by the goo.

Mature plants had an average of more than 70 insects stuck to them, primarily various species of gnat, which suggested a potential carnivorous habit, says team member at the Chinese Academy of Sciences.

The team first tested whether the secretions produced by the hair-like structures that trap insects contained digestive enzymes capable of breaking down the prey, and found they did.

Next, by infusing insect prey with a nitrogen isotope, the scientists were able to demonstrate that nutrients from the digested insect had been taken up by the plant.

Finally, genetic studies showed that Saxifraga shares common genes with other carnivorous plants – a sundew (Drosera spatulata) and a flycatcher bush (Roridula gorgonias) – that control prey attraction, digestion and nutrient uptake.

“Together, these genomic data provide independent evidence that S. candelabrum is a true carnivorous plant,” says Sun.

Soltis expects the team’s research will lead to a re-examination of other species in the genus, including the ones Darwin studied, and the wider Saxifraga family.

“Many members of the family have these hairs, and I would not be surprised if others are also carnivorous,” Soltis says.

A tiny, long-necked marine predator that lived 245 million years ago is the oldest reptile ever found with an intact digestive system.

The exquisitely preserved fossil, including almost the entire skeleton as well as the stomach, liver and intestines, was found in Yunnan province in China in 2023 and is named Austronaga minuta.

Even blood vessels and the scales of a partially digested fish meal are visible in the remains.

“A fossil this age with such clear preservation of its organs is really a world treasure,” says at Flinders University in Adelaide, Australia, who wasn’t involved in the research.

Austronaga dates back to the Triassic Period, when dinosaurs first evolved, but it isn’t a dinosaur. It belongs to a broader group called archosaurs, which includes dinosaurs, birds and crocodiles, but not other famous marine reptiles like mosasaurs or ichthyosaurs.

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The archosaurs were incredibly diverse in the Triassic and included “all kinds of interesting and strange-looking reptiles”, says at the Natural History Museum Stuttgart, Germany, a member of the team that analysed the fossil. Only later, during the Jurassic and beyond, did they become more restricted, mostly being limited to dinosaurs, including birds, and crocodiles.

This specimen is a mere 60 centimetres in length, but as it is the only known example and the reptile’s age at death is unknown, it is impossible to say whether the species grew larger, says Spiekman.

However, he is confident that it was unlikely to have reached the size of its very long relative Dinocephalosaurus, the “Chinese sea dragon”, which could easily grow to over 4 metres.

“This was certainly a good and agile swimmer, mainly using its tail for swimming, its long front flippers for steering and its long neck to catch fish,” says Spiekman. “A�ܲ��ٰ��DzԲ����� probably would have looked a little like a lizard or a croc trying to be a seal or an otter and likely would have had scaly skin, for example.”

The fossil shows that the basic plan of the reptilian digestive tract has changed little in 245 million years, he says, and the “straight and simple intestines is what we see in most modern predatory reptiles, including those eating fish”.

Although the fossil is of high quality, the internal organs of Austronaga are only preserved in two dimensions. This is unlike those of a 380-million-year-old fossil of an armoured fish that Long and his colleagues , which is regarded as having the oldest known organs of any vertebrate.

“But this is still an incredibly well-preserved fossil,” he says.

“Most people are completely unaware of what is in the water,” says Julian Cremona, a naturalist and photographer who is out to change that with his new book.

Plankton is an umbrella term for all kinds of different organisms floating in our waters, from plants, known as phytoplankton, to animals, known as zooplankton. They can be as little as 0.02 micrometres, the size of some viruses, or as big as 2 metres, the size of a large jellyfish. What they have in common is that they aren’t powerful enough to overcome the movement of water, unlike organisms that can resist the current. As Cremona writes, plankton are “drifting organisms that are unable to determine their long-term direction and are at the whims of the current”.

Cremona’s book is a guide to the different types of plankton found along the British coast, such as the larva of a Magelona worm, just 2 millimetres in size, in the main image. To take this photograph, Cremona fitted objective lenses from an old microscope to his camera.

Below is a shot of a tiny zooplankter, Oikopleura. Its body is made up of a trunk on top of a long tail, ranging from a few millimetres to a centimetre long. It has a lifespan of five to six days, over which it grows, reproduces and finally dies.

Some larger plankton are shown below, including a handful of compass jellyfish (Chrysaora hysoscella), which are mostly found in northern Europe. The umbrella of this jellyfish can stretch to 30 centimetres in diameter, and it uses its 24 tentacles to catch its food: small fish, crabs and other jellyfish.

Pictured below is a swarm of moon jellyfish (Aurelia aurita), the most common jellyfish to be found in the UK’s waters.

Some phytoplankton exhibit symbiosis with jellyfish and sea anemones, such as the aptly named snakelocks anemone (Anemonia viridis), pictured below. Single-celled Symbiodinium plankton live within the tissue of its green tentacles, where they perform photosynthesis and provide their host with carbohydrates. In return, the plankton receive inorganic carbon, nitrogen, phosphate – and a protected refuge in which to live.

A male jaguar has made an unprecedented trek, skirting 2100 kilometres of the southern edge of the Amazon rainforest. The journey – which crossed highways, farms, ranches and other human-modified landscapes – expands our knowledge of what these big cats are capable of.

was about 60 to 100 kilometres, says at University College Dublin in Ireland. Knowing these animals are capable of travelling much longer distances reveals further challenges in protecting them. “Individuals that are travelling so far are more exposed to human-related risks like hunting or killing because of attacks on livestock,” says Morant.

He and his colleagues have been tracking jaguars in Brazil via GPS collars as part of a larger ongoing project that started in 1999. The researchers wanted to better understand how jaguars use their environments along the Araguaia river, a potential wildlife corridor connecting the Cerrado grasslands with the Amazon.

They captured the male, dubbed Gaspar, as part of this work, fitting him with a collar on 11 November 2024. The 8-year-old jaguar then spent some time in his established range, about 700 square kilometres along the Araguaia river, before setting out on a massive southward trek, skirting the border of the Amazon to inland Cerrado.

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The researchers recorded that Gaspar travelled 2122 kilometres, until his collar stopped transmitting locations in late Novemeber 2025, but that is as the crow flies. The actual distance is probably much more, says Morant.

While Gaspar mostly stuck to forested areas, he also crossed through heavily modified human landscapes, such as farms, ranches and roads. Dispersals, albeit shorter ones, are common in individuals aged 1 to 3 years old that are looking to establish a new territory, but it is unclear why an older adult like Gaspar made this move. He might have been searching for better food resources, mating opportunities or a better habitat in general, says Morant.

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“Beyond the extraordinary distance travelled, I find [it] especially intriguing that he apparently did not establish a territory despite more than a year of continuous 
movement through areas that were, at least in part, potentially suitable for jaguars,” says at the Spanish National Research Council.

The findings also reveal an additional challenge in protecting such wide-ranging cats. In these human-modified areas, jaguars face threats from poaching, as ranchers often kill them to protect livestock. “Maybe we need to rethink how protected areas are framed and organised,” says Morant.

Gaspar’s fate is now uncertain. He may have been shot or poisoned, or the collar may have just stopped working, says Morant, which could mean Gaspar is still traversing the Brazilian landscape.

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