Bees seem to show when they are pleased and like something, rather than just needing it, in one of the strongest signs yet that insects have subjective experiences.

In recent decades, it has become clear that bees are capable of more complex behaviours than we previously thought, such as counting and demonstrating a sense of rhythm. But discerning whether they have inner states akin to our emotions is more difficult. For one thing, insects don’t have the flexible facial musculature of mammals, which we use to communicate our feelings.

“How can we get any behavioural readout of these insects with a hard body and their mask of a face,” asks at Macquarie University in Sydney, Australia. “Do bees have any sort of inner state whatsoever?”

To solve the mystery, Barron and his colleagues ran a series of experiments involving buff-tailed bumblebees (Bombus terrestris).

First, the team offered the bees a water droplet containing sugar, along with others that contained salt and quinine, while filming them using high-resolution video.

After tasting the sweet liquid, the bees repeatedly stuck out their glossa, which is a hairy tongue that they use to lap up nectar in flowers. After tasting the salty and bitter samples, the bees wiped their mouths and shook their heads.

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However, both responses may have just been a reaction to the different chemicals, rather than a sign of enjoyment or displeasure, says Barron.

Next, the researchers reduced the concentration of the sugar and mixed it with a small amount of salt, resulting in a dramatic reduction of the glossa protrusions. Then they exposed the bees to 40°C (104°F) temperatures to dehydrate them, after which, when the bees were offered salty droplets, the bees repeatedly protruded their glossa.

“If I just handed you an electrolyte drink right now, you’d probably think, ‘well, that actually tastes pretty foul’,” says Barron. “But if you had just come back from a long run and I handed you an electrolyte drink, you’d think, ‘that’s fantastic’. It’s because your internal state has changed, and that internal state is changing your evaluation of things – that’s what we think we’re seeing in the bees.”

For the final part of their experiment, the researchers wanted to determine what would happen if they meddled with the chemistry that, in mammals, underpins appetite and the enjoyment of food.

When the bumblebees were treated with dopamine, which in mammals affects the motivation to seek food, their glossa protrusions didn’t increase, suggesting that although they had greater desire, their enjoyment “tell” – tongue protrusions – didn’t change.

But when the bees were treated with endocannabinoids, which increases the “liking” of food in mammals, it led to an increase in their glossa protrusions.

“What this is showing us is that even from an animal like a bee, there is some sort of inner life for that insect,” says Barron. “There’s something going on. It’s evaluating its world. It’s experiencing its world and it’s not a robotic entity running on a program.”

at the California Institute of Technology says the research is “an important and innovative study on a difficult topic”. “The evidence presented in the paper shows that the bees represent the value of the taste stimuli in a flexible manner,” he says. But it is unclear whether the experiments demonstrate pleasure as we know it.

“The idea that facial expressions are literally constitutive of emotions is clearly not the case. Actors can fake them, and people whose faces are paralysed still have emotions,” he says. “I think we should conclude that bees have bee emotions, not mammal emotions.”

at the London School of Economics says the study is the first time he has  seen “wanting” and “liking” disentangled in a bee.

“We underestimate insects so much,” he says. “It’s led to a golden age of very charming studies where scientists use modern techniques – sometimes just high-resolution, high-frame-rate video, as in this study – to reveal behaviours people have been missing.”

Childbirth can be extremely challenging for humans – but some other primates may have it even worse. A comprehensive analysis of primate anatomy concludes that many species must squeeze large-headed infants through too-narrow pelvises. The problem may have begun with the very first primates, which lived more than 50 million years ago.

It has been assumed for decades that evolution has left humans with unique childbirth difficulties. The conventional view is that the trouble began when our ancestors first walked on two legs, which required the pelvis to be narrow. A few million years later, hominin brains evolved to be larger and infant heads became bigger – but the pelvis was unable to expand to allow for their easy delivery.

Other primates were thought to have things easier, largely because that was the conclusion of an published by anthropologist Adolph Schultz in the 1940s. Schultz looked at a range of primate species and concluded that in the vast majority, the infant head could fit comfortably through the female pelvis.

But his analysis was flawed, says at University College London. “One of the main problems was that it applied measurements that were originally developed for the human pelvis to all primates,” she says.

Schultz identified landmark points on the human pelvis that define the maximum width and depth of a horizontal plane at the top of the birth canal. He then assumed those same landmarks would define the maximum width and depth of any primate birth canal. They don’t. The human pelvis has a very unusual shape, and when Schultz’s landmarks are mapped onto other primate pelvises, they typically define an inclined plane that sits slightly above the birth canal. This plane overestimates the size of the birth canal, because it is effectively an oblique, oval-shaped slice through a cylinder representing the birth canal.

Torres-Tamayo and her colleagues reassessed birth canal shape in 29 primate species, while also looking at data on newborn-skull size and shape in each species. They concluded that several primates have a pelvis that seems too narrow to give birth. Small primates including bush babies and tamarins have the most severe conflict. In these primates, the newborn’s head is almost twice the size of the birth canal.

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“I was not expecting to have a mismatch in quite such a large number of primates,” says research team member , also at University College London.

Birth difficulties may even be the ancestral condition in primates, says Betti, particularly considering that early primates were small.

“It’s super cool to have such a big sample,” says at the University of Zurich, Switzerland. “These species are doing very different things, living in different niches and they do tend to be quite anatomically diverse.”

Different primates have also found their own solutions to the problem. For instance, the bush babies and tamarins dislocate the bones of the pelvis, temporarily doubling the size of the birth canal. Humans can’t do this, says Betti: it would make walking unbearably painful for a large, bipedal species.

Torres-Tamayo and Betti and their colleagues also found that birth difficulties are much less likely to arise in the great apes, maybe because they are so much larger than the tiny tree-dwelling primates. In this sense, humans are still unique in having birth difficulties, because we are the only large ape with the problem, says Betti.

But Webb isn’t so sure about this point; in a study she and her colleagues published in 2024, they concluded that between the size of the birth canal and the infant’s head. “That discrepancy is strange. It’s probably a reflection of the methods used,” says Webb. “This new paper is providing a really nice incentive for us to revisit our own hypothesis.”

Scientists have tracked the eye movements of a bird in flight for the first time, revealing that pigeons in the air lock their eyes in place rather than looking around. The behaviour may help them control their flight, but it could also leave them more vulnerable to predators.

If animals on the ground want to look at something, they move their head or eyes to fix their gaze on it, then use rapid and sometimes wide-ranging movements of the pupil, known as saccades, to give a stable view of the object relative to its surroundings. But no one really knows what happens when birds are flying.

To find out, at the California Institute of Technology and his colleagues designed a lightweight rig of mirrors and cameras that can be attached to the head of a common pigeon (Columba livia) as it flies, as well as a small backpack that houses a camera control board and battery.

They then trained six pigeons to fly between two perches about 20 metres apart indoors, and three to fly some 25 metres outdoors to return to a coop.

During test flights in both environments, the head-mounted eye-tracking system revealed that after take-off, the birds increased their pupil size and adopted a fixed and consistent eye position in their heads, essentially locking their eyes in place.

“Whenever they start flying, the eyes rotate forward on average,” says Ros.

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If their heads moved, their eyes moved in synchrony with them. The fixed eye position aligns with the primary horizontal axis of the birds’ vision and their vestibular system – the sensory network that controls balance and spatial orientation.

“Pigeons have been shown capable of moving their eyes independently and that they can be moved by a maximum amplitude of about 15 degrees,” says at the University of Birmingham, UK. “Therefore, to show that, during flight, eye movements are less than 1 degree does suggest that the birds are actively stabilising the position of their eyes when in flight.”

Why they are locking their eyes isn’t certain, says Ros. He thinks the alignment with the vestibular system suggests the behaviour may help pigeons distinguish their own motion from external motion – such as the movement of a tree’s branches, or a car or predator – to help them balance and navigate.

It’s also possible that reducing eye movements minimises the computational load on the brain. “The world during flight moves a lot faster than it does during non-flight,” he says.

Eye movements give pigeons a , but Ros says locking their eyes into a forward-facing position is likely to reduce this, leaving a larger blind spot behind them where they couldn’t see predators.

He is curious about what pigeon eyes would do in other situations, because all the tests were done when the birds were low to the ground. “It might be different if pigeons were flying higher up, where there aren’t lots of objects rushing past,” says Ros. He also wonders what would happen when pigeons fly in flocks. “Would they look at other pigeons? At predators? Or at something on the horizon?”

Martin thinks other birds might also stabilise their eye position during flight, including predators. When in pursuit of prey, , he says. “This presumably would require the peregrine to fix the position of their eyes rather than move them about.”

All of us who own a pet ideally want our beloved four-paws to live forever. Sadly, this kind of life extension is the stuff of science fiction. But we are increasingly in reach of the next best thing: extending the number of years our pets live their best lives, happy, active and full of vitality.

Until recently, a major goal of veterinary scientists was to maximise an animal’s lifespan. Today, the focus has shifted to increasing healthspan, the number of years an animal enjoys good health. “It’s not so much about how long we let them live, but how long we let them live a good life, a quality life, a functional and resilient life,” explains Dr Tanya Schoeman, a veterinary specialist physician with Royal Canin, a global supplier of pet food.

“We know that ageing is not a disease. It’s a physiological state that leads to disease. So we’re saying, let’s look at interventions that can take an organism that is in its prime and keep that plateau of form and function and resilience for as long as possible.”

The deterioration and disease that occurs in all organisms as they age is driven by a number of processes that take place at a cellular level. These include so-called “epigenetic” changes—chemical modifications to DNA—that affect how genes switch on and off as well as mutations and other changes that build up in DNA. Then there are the effects of the accumulation of damaging ‘senescent’ cells that no longer divide and dysfunction of the mitochondria that regulate cell energy. These are all hard to influence.

Cellular ageing

But researchers have pinpointed other factors too. For example, disruption in the balance of health-promoting microorganisms in the gut, chronic low-level inflammation (known as inflammaging) that leads to cell damage and disease as well as the ageing body’s impaired ability to detect the presence or absence of nutrients.

Some of these processes are known to affect dogs and cats in specific ways. For instance, impaired nutrient detection is likely one reason why dogs that are overfed throughout their lives develop disease and die earlier than dogs that consume fewer calories.

Changes in the gut microbiome are thought to be linked to age-related cognitive decline in dogs and cats. And inflammaging has been implicated in degenerative joint disease in cats, and in heart and kidney disease and various cancers in dogs. “Very often [the onset of disease] is where we as pet owners see the signs of ageing, but those processes have been going on inside the body for many years,” says Dr Schoeman.

For over 50 years, Royal Canin has been exploring how advanced nutrition might be used to support pets as they age. For example, one early-stage project is investigating how targeted nutritional profiles can optimally support the body’s natural systems and maintain overall vitality before the outward signs of structural decline begin to show.

In previous research, the company found that optimising the dietary balance of two different types of omega-3 fatty acids, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), can successfully support joint mobility and comfort. The new research is exploring how these specific dietary interventions can be used early on to promote long-term joint health and keep healthy pets moving comfortably for longer.

Alongside its scientific programme, Royal Canin is trying to raise awareness among pet owners that early intervention can increase their pet’s healthspan. A recent survey by the company, which questioned over 19,000 dog and cat owners in 18 countries, found that 44 per cent of owners never think about their animal’s ageing until noticeable signs of ageing appear, 38 per cent believe nothing can be done about it anyway, and 55 per cent avoid the subject because it makes them sad.

Dr Schoeman says it’s important to persuade owners that “ageing isn’t something to fear. It’s something that can be modified, and we can actively influence the trajectory of our pet’s ageing.”

What can owners do right now to help their pets age gracefully? The most important thing is to manage their weight: veterinary scientists agree that obesity is the number one risk factor for age-related disease, disability and death in all species. Exercise is also key, to keep muscles strong and to maintain cognitive health.

Finally, Dr Schoeman recommends incorporating healthy ageing conversations into regular annual health checks where a vet can carry out blood tests, check muscle mass and body condition, and start an ongoing conversation with the owner about how their pet is faring.

Healthy ageing

Healthy ageing in pets can look similar to healthy ageing in people, says Dr Brennen McKenzie, director of veterinary medicine at animal health company Loyal. But he says there is a crucial difference: pets don’t get to determine how or when they die. Most pets at the end of their lives are euthanised by their owners when the owners decide, usually with great reluctance, that they are suffering unduly or in severe decline. Consequently, extending their healthspan is the only way to make them live longer, says Dr McKenzie.

The death of a pet can feel as devastating as the death of a family member. Grief for a beloved animal may be unavoidable, but it would be comforting to know that they had lived a contented healthy life for as long as possible.

The essential thing, says Dr Schoeman, is to start thinking about ageing when your pet enters the midlife stage – around six or seven for most dogs and cats, and as early as five for large dogs with shorter lifespans. She acknowledges, however, that many people find the idea of their pet getting older hard to accept. “This is an emotional subject for pet owners. We’re talking about companions in our households that live our lives with us. That’s why we should see healthy ageing as a positive conversation. After all, every pet deserves more happy, healthy years sharing our lives with us.” Acting earlier in their lives can make a significant difference.

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Poaching and a changing climate forced the northern bald ibis (Geronticus eremita) out of the northern foothills of the Alps around 400 years ago. But now they are on their way back.

This photograph shows Helena Wehner flying in the passenger seat of an ultralight aircraft, singing a German song through a megaphone to guide the birds on their way to their new winter homes. Wehner, behind pilot Johannes Fritz, is part of an Austrian conservation group known as Waldrappteam – named after the ibis’s local name – which is trying to establish a healthy European population once more.

The birds are hand-raised by human carers and form bonds, which means they are happy to follow people even when they are riding in the aircraft. Since its inception in 2004, the migration project has amassed numerous followers and fans from local communities along the birds’ route. The 50-day journey covers 2800 kilometres from south-east Germany to south-west Spain.

The stunning shot of the formation flying over the olive groves of Jaén in the south of Spain was taken by student Gunnar Hartmann and won him the overall top spot in . Hartmann joined the conservation team as a volunteer in 2024 while a science undergraduate at the University of Koblenz in Germany. In an announcement about the awards, Hartmann said the image brought up “so many emotions” for him. “I can smell the air from this day and imagine the sounds,” he added.

Other winning photographs in the Scientist At Work competition include this image from deep in the Red Sea off the Saudi Arabian coast, below, taken by marine biologist Uli Kunz. It shows scientists installing an incubation chamber over a coral reef ecosystem. The project aims to understand how different corals – Acropora here – react to rising water temperatures caused by climate change by measuring their oxygen output.

The winning image below, taken by Robert Harcourt, shows biologist Michael Doane holding his breath and diving down to carefully skim the skin of a whale shark (Rhincodon typus) with a syringe at Ningaloo Reef off the coast of Western Australia, collecting a sample of the microorganisms that dwell there.

Another winning aquatic image, this time shot from above, shows algal blooms on Dog Lake in Ontario, Canada. The Microcystis aeruginosa and Dolichospermum flos-aquae create a “toxic, vile-smelling layer of rot” on the lake each summer, according to photographer Haolun (Allen) Tian, a PhD student at Queen’s University in Kingston, Canada. The thick green bloom kills fish and clogs water supplies. The boat in the image, shown below, contains scientists taking water samples for environmental DNA analysis.

Finally, photographer Shayanta Chowdhury captures an entomologist at the University of Notre Dame in Indiana observing a yellow fever mosquito (Aedes aegypti) under a microscope, below. Scientists are studying how the drug nitisinone can be used to kill blood-feeding insects, and the mosquito has been fed a sugar mixture spiked with both the drug and a fluorescent dye.