Extraordinary underwater videos have captured orcas making sunfish explode by ramming them at high speed. The behaviour may help juvenile orcas feed by breaking the prey into many small pieces, but it also appears that the orcas may enjoy playing with their food.

“It’s a hunting tactic, but that involves a play game in the process,” says , an independent marine biologist in Mexico. “There’s ‘high-octane’ adrenaline and a lot of other hormones rushing through their bodies, so, of course, there’s got to be some sort of excitement.”

Sharp-tail sunfish (Masturus lanceolatus) are among the largest bony fish, weighing up to 2000 kilograms. Higuera had already seen groups of orcas (Orcinus orca) attacking sunfish in the Gulf of California, ripping off parts of their flesh and tossing them around to each other in a playful manner. In the past few years, he had even witnessed them .

Then, in July 2024, his colleague at US non-profit organisation Beneath the Waves caught an explosive interaction on her GoPro camera while diving in the Gulf of California. An adult female orca held onto a dead sunfish while an adult male orca swam upside down towards it at full speed. The female released the sunfish at the last second, and the male hit it with so much force that the fish burst into a flurry of small fragments.

A year later, tourist Hector Franz shot a similar underwater scene in the same bay. This time, an adult female rammed right-side-up into a sharp-tail sunfish held in place by another adult female, popping it into pieces. Combined, the two events mark the first time scientists have seen such behaviour by orcas, say Higuera, Ayres and their colleagues.

Sunfish have “an incredibly dense, rubbery, collagenous” outer layer that’s harder to bite through, so bursting them open could be an effective way to feed on them, says Higuera.

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“The explosive fragmentation seemed mostly to be of the stiff gelatinous capsule that makes up a high percentage – more than 80 per cent in large fish – of the body mass of the sunfish,” says at University College Cork in Ireland. “I suspect that calves cannot achieve enough force to do this, as their mass is too low. But they can exploit a cloud of objects that contain tasty morsels.”

Earlier sightings without full footage indicated that the entire pod was involved in a strategic attack process leading up to the rammings, says Higuera. The findings point to advanced cooperative hunting skills and even planning – especially adapting their techniques for different kinds of prey, he says.

Higuera suspects that popping the sunfish offered a learning experience for the calves, while providing them with bite-sized snacks. Simultaneously, these events could also reinforce social bonds through “play” and social learning in this highly intelligent species, he adds.

at the University of Tennessee in Knoxville says it is possible the orcas were having some fun in demolishing the fish, but play wouldn’t be the only goal, as there is clearly cooperative foraging going on as well.

“One of the fascinating things about play is that it can be a driver of behavioural innovation,” says at the University of Pisa, Italy. “It’s possible that a behaviour like this may have originated in a playful context and later acquired a feeding function, or vice versa. At this stage, we simply don’t know.”

A man who became paralysed after a diving accident six years ago regained the ability to move and feel pressure in his hands thanks to brain stimulation. Now, researchers have revealed he maintained this ability for months after the stimulation was turned off. This suggests the intervention has caused a rerouting of his neuronal connections through neuroplasticity.

“We turned everything off completely, for many months, and yet he’s maintained these gains,” says at the Feinstein Institutes for Medical Research in New York. “That’s unheard of.”

Keith Thomas, 48, was paralysed from the chest down in July 2020. He had no sensation or control over his limbs and had significant muscle wasting, says Bouton.

In 2023, Bouton and his colleagues performed a double neural bypass surgery on Thomas, placing five electrodes into his brain in regions associated with arm movements and feeling. They then connected computer cables to these electrodes, so artificial intelligence could interpret his movement intentions. That information was then wired into electronic splints that stimulated his arms, hands and fingers to carry out his intended movements, enabling him to pick up coffee cups and scratch his face.

To recreate the sense of feeling, the team embedded force sensors into 3D-printed wearable devices for Thomas’s hands and fingers, which sent feedback via electrical stimulation into the brain’s sensory areas.

After conducting a series of experiments – which even involved Thomas feeling objects through another person’s hand – Bouton says the team planned to stop the stimulation for about a month, to test for any lingering effects. “Then we had a fire in the building, and it actually forced us to stop stimulation for even longer than we’d planned, for about three months.”

The unexpected interruption led to surprising findings: Thomas continued to maintain strength, feeling and function in his hands. “He’s now also controlling individual fingers with even more accuracy, so that’s big,” says Bouton.

In a video interview with �鶹��ý, Thomas raised his elbows nearly to shoulder level and described feeling “tingling” in his wrist in response to pressure, even when he’s “unplugged from the computer”. “When I first felt it, it was amazing,” he says. “I’m used to it now.”

 at the University of California, Davis, says the work suggests that this approach promotes lasting recovery of the nervous system. “The goal is to help the nervous system partially heal so the person can move their own body better,” he says.

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“If these improvements persist even when the system is turned off, then the device is doing more than temporarily restoring function,” says at the University of California, Los Angeles. “It may be helping the nervous system reorganise itself through neuroplasticity.”

This describes the brain’s ability to rewire itself by forming new neural connections, such as or even . “After an injury such as spinal cord injury, those same mechanisms may help restore function by strengthening spared pathways or recruiting alternative circuits, allowing neural signals to travel through networks that were previously too weak to support meaningful movement,” says Lu.

The researchers have observed stronger neural responses in Thomas’s sensory cortex since the intervention.

But this is just a single case report, so it’s unclear how well this approach would work on other people with paralysis from different types of injuries. at the University of Chicago says he has spent years working on stimulation and continues to find that some respond better than others, and some not at all. “And we have no idea why,” he says. “So, the question is: can you replicate it? This is a really ambitious study, but we need to see them replicating their results in more participants before we believe the hype.”

As to Thomas’s future, “at this point now we know nothing’s impossible, or anything’s possible”, says Boulton. “I think it’s possible he will continue to to improve,” he adds.

Brushing your teeth while being treated in hospital can significantly reduce your chances of falling ill with pneumonia.

Many hospitalised patients don’t brush their teeth during their stay, probably for a variety of reasons. Some may have forgotten to bring a toothbrush, while others don’t think about it, feel unmotivated or are physically incapable of doing so. Medical staff often do not include routine oral hygiene care as part of their services to patients.

But in the largest randomised controlled trial of its kind, patients equipped with a toothbrush, toothpaste and dental care advice in hospitals were 60 per cent less likely to develop a common form of hospital-acquired pneumonia, says at Avondale University in Australia.

“This just really enforces the need for communication with patients about pneumonia risk, and the importance of oral care and brushing their teeth whilst in hospital,” he says.

It’s widely understood that patients on often develop pneumonia, due, in part, to the medical equipment interfering with the natural respiratory system. But many non-ventilated hospitalised patients also acquire pneumonia at least 48 hours after hospital admission. Researchers are still trying to understand why this happens and how to prevent it – particularly since hospital-acquired pneumonia is linked to .

“It’s an important problem,” says at Harvard University, who was not involved in the study. “Hospital-acquired pneumonia is one of the most common and deadly healthcare-associated infections, and rigorous data on how best to prevent it are sparse.”

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Mitchell suspected the disease might be linked to the bacteria in people’s mouths. The oral microbiome can affect respiratory health, as people breathe bacteria-laden droplets into their lungs. And the oral microbiome changes when people are hospitalised, says Mitchell. “I felt it was important that we try to do something to address this.”

So, he and his colleagues developed a year-long randomised controlled trial involving 8870 patients in three Australian hospitals to test the effects of oral care on pneumonia risks. He presents the results of this part of the team’s Hospital-Acquired Pneumonia Prevention (“HAPPEN”) study today at the in Munich, Germany.

Each participating hospital divided its study participants into three groups. None of the groups received any intervention for the first three months of the study. After three months, the patients in one group were provided with toothpaste and a toothbrush, labelled “Brushing teeth helps prevent pneumonia” on one side and “Brush away pneumonia!” on the other. The brushes were designed with a special handle for people with reduced dexterity. Patients also received a QR code linking them to educational materials on the .

After six months, the second group also received the toothbrushes, and the third group was given toothbrushes after nine months – meaning all study participants had the option of brushing their teeth for the final three months of the study.

As for the healthcare staff, the research team organised oral care training for ward nurses and provided them with links to professional advice on their website. They also encouraged the nurses to remind patients to brush and floss their teeth and to help those who had difficulty doing so themselves.

Outside of the intervention periods, only 15.9 per cent of the patients brushed their teeth once a day. During the intervention periods, 61.5 per cent of the patients attended to their oral care at least once per day – with patients doing so 1.5 times per day on average. Web statistics revealed that both patients and nurses frequently accessed the information on the HAPPEN pages during the intervention periods, says Mitchell.

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That coincided with a dramatic drop in the number of cases of non-ventilator-associated hospital-acquired pneumonia, says Mitchell. Specifically, the incidence fell from 1 case per 100 admission days in the control group to 0.41 in the intervention group.

“This study is intriguing,” says Klompas, who highlights the large study size and randomised design. “The message is that brushing teeth while in hospital is not only good for one’s oral hygiene and sense of well-being, but it may also literally be life-saving.”

at the University of Helsinki, Finland, says he appreciates the importance of such a significant risk improvement based on such a simple intervention. “Basically the patients were just provided with toothbrushes, toothpaste and advice,” he says. Even so, results might vary depending on reasons for hospitalisation and the patients’ usual oral hygiene habits.