There are some stories that stay with you forever, the big scientific moments that change the course of history. These are not those moments – but we can’t stop thinking about them anyway.

Push my button

Surgeon Stuart Meloy was performing a pain-relief operation on a woman’s spine when she started exclaiming emphatically. “You’re going to have to teach my husband to do that,” the woman said. This inspired Meloy to invent an implant to help women who are unable to achieve orgasms in the usual way. New Scientist broke the news in 2001, sparking a frenzy of worldwide media excitement. But 13 years later, Meloy was still struggling to raise funds for a full clinical trial, and the “orgasmatron” never reached a climax.

Monkey pleasure

We aren’t the only primates capable of coming up with creative ways to pleasure ourselves. In a study of long-tailed macaques (Macaca fascicularis) in Bali, Indonesia, at the University of Lethbridge in Alberta, Canada, and her colleagues filmed hundreds of examples of male and female monkeys using stone tools as sex toys, rubbing or tapping them on their genitals. According to at the University of Western Australia, the Balinese monkeys get plenty of food handouts from humans, and this frees up time for sexual experimentation. But some monkeys in other places have unusual kinks, too: another study reported a wild macaque in Japan rubbing its genitals on the back of a sika deer.

Head transplants

In 2015, surgeon Sergio Canavero announced plans to carry out the first human head transplant, intended to extend the lives of people with muscle and nerve degeneration or widespread cancer. He claimed his technique could overcome technical hurdles, including how to fuse the spinal cord and prevent the body’s immune system from rejecting the head. In the following two years, Canavero published animal experiments supposedly backing up his methods, but other surgeons remained highly sceptical. A human head transplant never did happen, but Canavero has reportedly moved on to an even bolder ambition:

Rats driving

Have you ever wondered if a rat can drive a car? Kelly Lambert at the University of Richmond in Virginia has. She and her colleagues built a tiny car with three copper bars that would steer it left, forward or right. Sure enough, 18 rats learned to drive towards food rewards. They even found it relaxing, as measurements of their stress hormones indicated. Lambert proposed that driving challenges could replace traditional maze tests when using rat models to study neuropsychiatric conditions.

The sniff test

Humans are more similar to rats than we like to think. In a psychology experiment, and his colleagues at the Weizmann Institute of Science in Rehovot, Israel, surreptitiously filmed 153 volunteers. After shaking hands with someone of the same sex, people smelled their shaking hand more than twice as much as they did before the handshake. Puzzlingly, after shaking hands with someone of the opposite sex, people were more likely to sniff their non-shaking hand. The team suspected that humans use chemical signals all the time without being aware of it.

Urine fountains

Communication through scent is, of course, widespread in mammals, but some never-before-seen behaviour in dolphins took biologists by surprise in 2025. While studying Amazon river dolphins (Inia geoffrensis), or botos, in Brazil, Claryana Araújo-Wang at CetAsia Research Group in Ontario, Canada, saw a male “flip his belly up out of the water, expose his penis and then proceed to urinate into the air”, she told New Scientist. They saw dolphins do this a total of 36 times, and most of the time another male was nearby and would pursue the stream of urine. The purpose of this behaviour hasn’t yet been established, but hormones in urine might signal a male’s social position or physical condition, said Araújo-Wang.

Giving the finger

As for human modes of communication, many of us struggle to put our smartphones down – so the last thing we’d want is for them to crawl across the table towards us. Nevertheless, Marc Teyssier at the University of Paris-Saclay in France and his colleagues gave phones this ability in 2018, with a robotic appendage dubbed the MobiLimb. It plugs into a device’s USB port and, for some reason, looks eerily like a human finger, giving it a spooky quality reminiscent of Thing from The Addams Family. The MobiLimb can stroke your wrist, wave, wag like a tail or, most disconcertingly, drag the phone around. Thankfully, the idea hasn’t taken off.

Horror frog

If you find the thought of a phone with a finger horrifying, wait until you hear about the nightmare-inducing hairy frog Trichobatrachus robustus. In 2008, researchers reported that these frogs can break their own bones to produce claws that burst through their skin. at Harvard University’s thought these weapons were for defence, but two years later, that they were used in fights between males – and that the frog’s unusual hairs were a kind of armour to protect its vulnerable parts from sharp claws.

Corpse shrinking

In 1957, when New Scientist was 1 year old, we reported on a new method for shrinking an adult human body to the size of a baby. At an exhibition of inventors in Winnipeg, Canada, the unnamed inventor of this process claimed it would make disposing of dead bodies simpler, as they could be slid into underground tubes and take up less space. The method involved applying high pressure to the corpse and squeezing out fluids so its flesh could be compressed into a mould. “All this is, of course, highly ingenious but it is uncertain why the inventor thinks that his newly proposed form of burial is in any way better than the current and very popular method of cremation,” the writer mused.

Transient anus

We may take it for granted, but the anus, which allows food to pass through the body, was an evolutionary breakthrough, both figuratively and literally. The earliest animals, like jellyfish today, had only one gut opening, where food went in and waste came out. In 2019, scientists discovered that the warty comb jelly (Mnemiopsis leidyi, pictured top) forms an anal opening when it needs to defecate, but it vanishes straight afterwards. This, they suggested, could represent how the anus evolved in the first place.

Fart science

Flatus – gas expelled from the anus – has been a topic of endless fascination for many readers (and journalists). In 2001, we featured the work of Michael Levitt at the Veterans Administration Medical Center in Minneapolis, a leading authority on the subject. He developed a “Toot Trapper” that reduces odours by trapping certain gases using activated charcoal. We also reported on a device for monitoring gas emissions from dogs, used to test dog snacks that were supposed to reduce flatulence. In 2016, researchers in Australia worked out which foods cause the smelliest farts by mixing faeces with different foods. They recommended eating less protein and more slow-release carbohydrates to minimise hydrogen sulphide production. In 2022, at the Mayo Clinic in Rochester, Minnesota, and his colleagues worked out that some poos float because of gas from gut microbes, confirming a hypothesis first put forward by Levitt 50 years earlier.

Brew your own

Even stranger things go on inside some people’s intestines, as we found out in 2019. A 46-year-old man started experiencing unexplained mental fogginess, dizziness and memory loss, and had to give up his job. Later, doctors found high levels of alcohol in his blood when he hadn’t been drinking. Eventually, they realised his gut contained high levels of Saccharomyces cerevisiae – brewer’s yeast – which got him drunk any time he ate a lot of carbohydrates. This rare condition, known as auto brewery syndrome, had been triggered when the man took antibiotics for a thumb injury, which disrupted his gut microbiome. This year, a study reported that another man with this condition fully recovered after getting a transplant of faeces from a healthy donor. Both articles were written by Alice Klein, who we also have to thank for the monkey sex toys, car-driving rats, smelly farts and floating poos. Thanks, Alice!

In 2013, deep inside South Africa’s Rising Star cave system, scientists discovered the remains of Homo naledi, an ancient human species with a brain just one-third the size of ours. Yet some evidence suggests they may have intentionally placed their dead there. If true, this would push the birth of burial rituals back hundreds of thousands of years and challenge the idea that complex emotions like grief require big brains. Were these ancient humans performing funerals? Or are we reading too much into the evidence? This is the story of Homo naledi and a discovery that forces us to rethink what it truly means to be human.

People who experience long periods of intense grief after the death of a loved one seem to have a higher risk of dying within the next decade than those who come to terms with their loss more easily.

Numerous studies have linked bereavement to poor health outcomes, such as . But most of these only tracked the bereaved for a few years after their loss, says at the University of Zurich in Switzerland, who wasn’t involved in the latest research.

Now, at Aarhus University in Denmark and her colleagues have examined how grief is linked to mortality up to a decade later.

The researchers used a national registry to obtain information on people who were being treated for a terminal condition. They then recruited more than 1700 of these people’s loved ones, such as a parent or partner, to complete a series of surveys – taken before their death and six months and three years after. These asked the loved ones – who were aged 62, on average – questions, like whether they were trying to avoid reminders that the person was ill or dead.

The team found that 670 of the loved ones were persistently experiencing low levels of grief after the death, such as feeling slightly confused about their role in life, while 107 of them were persistently experiencing high levels of grief, such as overwhelmingly feeling this way. The remaining participants experienced either grief that declined or delayed grief that kicked in some time after their loss.

Next, the researchers analysed the loved ones’ medical records 10 years after their loss. The death rate in the high-grief group was 88 per cent greater than in the low-grief one.

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“There’s a saying that bereavement breaks hearts,” says Maercker. The findings support the idea that prolonged, intense grief puts a strain on the body, leading to earlier death, he says. It may also bring about lifestyle changes, as bereaved people might be more likely to .

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Only 17 per cent of the loved ones had been diagnosed with a medical condition at the start of the study, but Nielsen says this was more common among people in the high-grief group. Higher rates of pre-existing conditions may partly explain why members of this group were more likely to die during the follow-up period, she says. It is also possible that poor health may intensify grief, says Maercker.

Offering extra support to people experiencing severe, prolonged grief – regardless of whether they have a condition themselves – could save lives, he says.

From a young age, the inevitability and finality of death becomes a shaping force in our lives. Indeed, it could be said that our ability to recognise our eventual demise and the grief that comes with losing those close to us are core elements of what it means to be human. They have also led to symbolic practices that have deep roots in human culture.

We have long assumed that Homo sapiens was the only human species to have gained an awareness of the mortality of living things. But as we report in “What were ancient humans thinking when they began to bury their dead?”, archaeologists are eager to question the idea that a deep and emotional response to death is our sole preserve.

The most challenging of their claims is that ancient humans who were very unlike us developed death rituals. But evidence is mounting that Homo naledi, an ancient human from southern Africa with a brain one-third the size of your own, buried its dead at least 245,000 years ago. Exactly why these small-brained humans may have felt compelled to develop a culture of death is unclear, but one intriguing – if speculative – idea is that they did so to help youngsters come to terms with the loss of a group member.

Much controversy surrounds the claim that H. naledi buried its dead, largely concerning the quality of the evidence. But since the mid-20th century, researchers have been busily narrowing the behavioural gap between our species and others, spearheaded by research showing that many animals have emotionally rich lives. Some even develop their own rituals when confronted with the death of community members. Throw in evidence that our ancestors were developing their own artistic culture at least 500,000 years ago and it is easier to accept that H. naledi was capable of developing its own burial traditions.

Archaeologists are questioning whether a deep response to death is our sole preserve

The provocative image of a grief-stricken H. naledi helping its young deal with loss forces as much of a rethinking about these ancient relatives as it does a reckoning of what it means to be human – and whether we are as special as we like to think.

When it comes to living a long life, it seems not all organs are created equal. Scientists have found that having a youthful brain or immune system may be key – more so than having a slowly ageing heart or lungs.

We already knew that organs age at different rates, but it is unclear which ones have the biggest influence on lifespan, says at the Icahn School of Medicine at Mount Sinai in New York.

So, Oh and his colleagues analysed the levels of nearly 3000 proteins in blood samples collected from more than 44,000 people who enrolled in the UK Biobank study when they were between 40 and 70 years old.

Using genetic data from past studies, the team was able to build a picture of where these proteins were in the body, pinpointing dozens of proteins that are especially abundant in 11 areas: the immune system, heart, brain, liver, lungs, muscles, pancreas, kidneys, gut and fat tissue. The high levels of these proteins indicate they are important in the proper functioning of these organs and body systems.

Next, the team trained machine-learning models to guess how old the participants were based on data from about half of them, creating a separate model for each of the 11 parts of the body. While these estimations generally matched the participants’ ages fairly well, some models overestimated or underestimated it, supporting the idea that organs age at different rates, says Oh.

The researchers used the trained models to predict the organ and immune system ages of the remaining half of the participants, who were followed for an average of 11 years after their blood was sampled.

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Oh and his colleagues found that having one prematurely aged organ, or an aged immune system, was linked to a 1.5- to 3-fold increased risk of death during the follow-up period, with the risk rising alongside the number of aged areas.

For the most part, having organs like a heart or lungs that appeared to be substantially younger than expected wasn’t linked to a reduced risk of death during the study period. The exceptions were those with the most youthful brains or immune systems, whose risk of death was reduced by about 40 per cent – rising to 56 per cent if both of these parts of the body were particularly youthful.

“The brain and immune system coordinate a lot of other things around the body, so if those go wrong, it’s not too surprising they might have outsized effects on lifespan,” says at Columbia University in New York.

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But it is unlikely that protein markers perfectly reflect the ageing process, says Cohen. “We may have incomplete knowledge of what proteins really come from what organs, and the proteins from a given organ might be better represented in the blood than other organs; that could be why certain organs pop out as more important,” he says.

What’s more, the participants were mainly wealthy and of European ancestry, so further studies involving more ethnically and economically diverse people should verify the findings, says at King’s College London. Oh says the team is planning research that addresses this.

Even if the findings hold true, we don’t have ways to specifically reduce ageing of the brain and immune system, says Oh. However, identifying markers of brain and immune ageing could help to develop drugs that target these to boost longevity.

Having nightmares on a weekly basis seems to accelerate ageing – and could even triple the risk of early death.

“People who have more frequent nightmares age faster and die earlier,” says at Imperial College London.

Along with his colleagues, Otaiku analysed more than 183,000 adults, aged 26 to 86, who had taken part in several studies. At the start, the adults self-reported how often they had nightmares, and were then tracked for as little as 1.5 years to as long as 19 years.

The researchers found that those who reported having nightmares on a weekly basis were more than three times as likely to die before they turned 70 than those who said they never or rarely had nightmares.

There is a clear association, says Otaiku, whose team also found nightmare frequency to be a stronger predictor of premature death than smoking, obesity, poor diet or lack of physical activity. He will present the results at the in Helsinki, Finland, on 23 June.

The team also assessed the participants’ biological age by measuring the length of their telomeres, which are small DNA sequences at the end of chromosomes that shorten each time a cell divides, with . This part of the study also included data from about 2400 children, aged between 8 and 10, whose nightmare frequency was reported by their parents. The adults had their biological age additionally assessed via molecular markers known as epigenetic clocks.

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Otaiku says the team found a consistent association between frequent nightmares and accelerated ageing across all ages, sexes and ethnicities. “Even in childhood, people who have more frequent nightmares have short telomeres, indicating faster cellular ageing,” he says. Among the adults, the faster biological ageing accounted for about 40 per cent of their heightened mortality risk.

As for why this association occurs, Otaiku says it could stem from two factors. The first is that nightmares cause prolonged high levels of the stress hormone cortisol, which has been . “Nightmares often wake us with our hearts pounding, in a stress reaction more intense than anything we experience when awake,” he says.

The second factor is disrupted sleep, which upsets the body’s overnight cellular repair processes. Sleep disruption has been linked to increases in the risk of various medical conditions, including .

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If people want to avoid regular nightmares, there are often easy ways to do it, says Otaiku, including not watching scary movies and seeking treatment for mental health conditions like anxiety.

“It’s an interesting finding and there is lots of biological plausibility,” says at Guy’s and St Thomas’ NHS Foundation Trust. However, he says, more research is needed to establish a causal link. Nightmares can be associated with a range of medical conditions and medications that people could have as they get older, which could be confounding the results, he says.