
Scientists warn some dogs and cats are being bred to evolve the same 'smushed' faces - and it could lead to breathing, eating and birthing issues
But flat-faced dogs and cats have been bred to such extremes that they now look more like each other than their own ancestors, experts reveal.
Humans have pushed breeds such as Pug dogs and Persian cats to evolve with very similar features including broad skulls and short snouts.
These characteristics, termed 'brachycephalic', have led to a range of health problems – most notably issues with breathing, eating and even giving birth.
For the first time, scientists have uncovered examples of how breeding these cats and dogs has led to 'convergence' – the tendency of unrelated animals to evolve similar characteristics.
Both species shared a common ancestor but have been evolutionarily separated for 50 million years.
However, flat-faced cats and dogs have converged to such an extreme that they are more similar to each other than they are to most members of their own species or their ancestors.
This phenomenon hadn't previously been observed in domesticated species, according to the paper.
Flat-faced dogs and cats have been bred to such extremes that they now look more like each other than their own ancestors, experts reveal. Pictured: a Pug dog and a Persian cat
'Persian cats and Pug and Pekingese dogs all have skull shapes that are very similar to each other, with flat and short faces, and their muzzles and palettes are tilted up in the same way,' said Dr Abby Drake, senior lecturer at Cornell University.
The researchers mapped the skull shapes using CT scans, compared them and discovered these similarities, even though the ancestors of cats and dogs looked quite different.
Dogs descended from wolves, a larger animal with a long muzzle, while cats descended from wildcats, which are smaller animals with a shorter face and a snout.
'They start off in different places but because humans applied the same selection pressures they evolved to look almost identical to each other,' Dr Drake said.
The same pattern of convergence has also occurred multiple times within each species, the researchers said.
In dogs it occurred in Bulldog breeds, but then separately in Asian dog breeds such as Pekingese and Shih Tzu.
In cats, the same traits can be seen in Persian, Himalayan and Burmese breeds.
Artificial selection from breeding has led to a remarkable diversity of both cats and dogs, though dog diversity is even more extreme, the team said.
'We're seeing this very large evolutionary variation within a species that's only been evolving for a relatively very short amount of time,' Dr Drake added.
'That's a remarkable thing to see in evolution, which takes millions of years, but we did it with dogs by pushing them to the extremes.'
The study, which was published in the Proceedings of the National Academy of Sciences journal, also included experts from Washington University.
They wrote: 'Brachycephalic cat and dog breeds have predispositions to many health disorders, some shared between species.
'As a result of these afflictions, pressure is mounting to ban the breeding of extreme brachycephalic individuals.
'We can hope such measures succeed for the welfare of our household companions, even if it has the effect of reversing this remarkable case of convergent evolution.'
Earlier analysis has revealed that owners of flat-faced dogs see some of their traits, such as laziness, as a good thing rather than a sign their pet is unwell.
The study from the Royal Veterinary College (RVC) found that the extreme conformations of French bulldogs, pugs and English bulldogs have been normalised.
And despite a high risk of developing significant respiratory problems due to their flattened face, eye conditions due to their bulging eyes and skin infections due to their deep skin folds, many owners still believe 'nothing' could put them off buying the breeds.
Commenting on the new findings Dr Rowena Packer, Senior Lecturer in Companion Animal Behaviour and Welfare Science at the Royal Veterinary College, said: 'From a biological perspective, it is remarkable that humans have moulded both dogs and cats into such an extraordinary array of morphologies, particularly skull shapes.
'However, this selection has largely been driven by human-centric desires, including the inherent attraction many of us have towards the 'cute' smushed faces of brachycephalic animals, perpetuating their international popularity.
'Modern animal welfare science has documented the severe and chronic harms that flat faces inflict, leading to long-term suffering in our canine and feline companions.
'Consequently, there is an urgent need for puppy and kitten buyers and breeders, as well as international policymakers, to reject these extremes and shift selective breeding back towards moderate, natural body shapes that confer animals the ability to live long, healthy and happy lives.'
Previous research has also found that flat-faced breeds have a 40 per cent increased risk of dying compared to other breeds.
For example, popular French Bulldogs have an average life expectancy of 9.8 years compared to Border Collies, who live for around 13.1 years.
The word 'brachycephalic' means short or broad-headed.
There are lots of pets selected for this appearance which have short snouts and flat faces.
Examples include the Pug, Bulldog, Boxer, Pekingese, Persian cats, British shorthair cats and Netherland Dwarf rabbits.
Because of this extreme body shape, flat-faced animals have a much higher risk of developing numerous painful illnesses and diseases than others.
Health and welfare problems associated with brachycephaly include:
- Anatomical defects of the upper airway causing breathing difficulties often associated with overheating, sleep apnoea, and regurgitation
- Eye disease
- Inability to mate or give birth naturally (requiring a Caesarean section)
- Repeated skin infections
- Dental problems
Many owners aren't aware that the 'cute' way their pet looks can cause serious and often life-limiting health problems and compromise their welfare.
Hashtags

Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles


Daily Mail
5 days ago
- Daily Mail
Is this how the world will end? Scientists give terrifying glimpse into the 'Big Crunch' - and reveal the exact date it could happen
From alien invasions to robot uprisings, there is no shortage of terrifying ways that the world might end. But scientists have now worked out exactly when one terrifying scenario could bring the universe to a close. According to the 'Big Crunch' theory, the universe will eventually collapse in on itself in a final climactic implosion. As space itself contracts, the temperatures will soar until everything is destroyed in the 'furnace of this cosmic hell'. Finally, the entire cosmos will find itself packed back into an infinitely dense singularity just like it was before the Big Bang. While this was once just a terrifying possibility, new measurements of 'Dark Energy' suggest the Big Crunch is the most likely outcome for the Universe. In a recent study, scientists from Cornell University calculated exactly when the 'Big Crunch' could begin. Thankfully, their calculations suggest we can relax for the time being... that is if something else doesn't cause our demise. What is the Big Crunch? The Big Crunch is essentially the opposite of the Big Bang which started the universe 13.8 billion years ago. After the Big Bang, the universe rapidly expanded as a sea of superheated matter cooled into the familiar particles which make up the cosmos today. During the Big Crunch, this process will run in reverse - compacting space back into a hot, dense state. Scientists believe the current outward expansion of the universe is due to a mysterious force called Dark Energy. If the pushing force of Dark Energy was constant, the universe would keep on expanding and cooling for ever. But now, astronomers are beginning to question whether this really is the case. Based on the latest data, some scientists believe that Dark Energy is weakening, leaving an inward force called the cosmological constant to pull the universe back together. The latest map of the known universe suggests that dark energy is getting weaker, which means the universe will one day fall back in on itself like a ball falling back to Earth under the influence of gravity What is the Big Crunch? The Big Crunch is essentially the reversal of the Big Bang. In the first few moments of the universe, space and time expanded rapidly and cooled to form the matter we now see around us. In the Big Crunch, all this matter will once again contract inwards towards that same infinitely dense point. As it collapses, space will become hot, and matter will be torn into a soup of fundamental particles. Eventually, the cosmos will be compressed into a singularity, just as it was before the Big Bang. Dr Ethan Yu–Cheng, of Shanghai Jiao Tong University, told MailOnline: 'It is just like throwing a basketball vertically upwards in daily life. 'The negative cosmological constant acts like the Earth's gravity, which pulls the basketball downward. The basketball will de–accelerate until reaching the maximum height and start to fall.' Would we notice the Big Crunch starting? If it's difficult to imagine what life during the Big Crunch would be like, think about the universe as a balloon with lots of little dots drawn on its surface. As you blow air in, the balloon expands, the surface stretches, and the distance between all the dots grows larger. The Big Crunch is like letting all the air out of the balloon at once, bringing those distant points back together in a rush. However, the process would start very slowly. Dr Hoang Nhan Luu, a researcher at the Donostia International Physics Center, told MailOnline: 'Intelligent civilisations at the scales of solar systems or even galactic scales would not notice any obvious phenomenon because these changes happen at much larger cosmological scales. 'Civilisations like us typically exist on time scales of hundreds to thousands of years while the changes happen on billion–year time scales, so we wouldn't notice any obvious day–to–day phenomenon until the very last moment.' But Dr Luu says that any observant humans still alive in the universe would be able to spot the warning signs. Just as we can look at distant galaxies to see that the universe is expanding, astronomers of the future would be able to see that the galaxies are now rushing towards them. What would the first signs of the Big Crunch be? The first obvious sign that the universe was changing would be that the cosmic temperature would start to increase. Professor Avi Loeb, a theoretical physicist from Cornell University, told MailOnline: 'It is the reverse history of our expanding universe.' The universe has been getting colder as it expands, like gas escaping from a pressurised container. During the Big Crunch, this process will play out in reverse and raise the temperature of space. Why will the Big Crunch happen? Some scientists believe that the universe's current expansion is determined by two factors. A negative 'cosmological constant' pulling the universe inwards and an outward force from Dark Energy. If Dark Energy were constant, the universe would keep on expanding forever. However, researchers think that Dark Energy is getting weaker. When it gets weak enough, the cosmological constant will overpower Dark Energy and pull the universe inwards. About 13 billion years from now, Professor Loeb predicts the density of energy in the universe will be about 1,000 times higher than it is now. Just half a billion years after that, it would be another 1,000 times higher, making the universe room temperature. Professor Loeb says: 'At this point it wouldn't be the sun warming that is warming us, but the equivalent of the Cosmic Microwave Background.' Within a few million years, the entire universe would be as hot as the surface of the sun. Eventually, the universe would reach the 'Planck temperature', the highest possible temperature according to our models of physics. Professor Loeb says: 'Needless to say, all humans will burn up in the furnace of this cosmic hell. What will happen to the solar system during the Big Crunch? During the Big Crunch, the universe will eventually become so dense that the planets and stars will be pushed together by the collapse. The only thing that will survive the collapse at first will be black holes. Black holes will actually thrive during the Big Crunch as they feed on a soup of ultra–dense matter That means the planets of the solar system will come closer and closer together until they are crushed together. As space approaches the final moments of the crunch, Professor Loeb says that the universe will be even denser than space inside an atom. As the universe becomes even denser than an atomic nucleus, all matter in the cosmos will once again be squeezed back into this primordial state. The only things in the universe to survive this transition would be black holes, which would thrive as they feed on the dense matter all around them. Finally, this boiling mess of black holes and elementary particles would be crushed into a single infinitely dense point known as the singularity, bringing the universe to an end. When will the Big Crunch happen? Thankfully, scientists believe that the Big Crunch is still far off in the impossibly distant future. Professor Henry Tye, a leading cosmologist from Cornell University, 'We calculate that this will lead to a big crunch about 19.5 billion years from now. 'Knowing that the age of the universe is 13.8 billion years, one obtains that the lifespan is 33.3 billion years. In their pre–print paper, Professor Tye and his co–authors, Dr Luu and Dr Yu–Cheng, say that the Big Crunch will begin about 11 billion years from now. The crunching phase would then last around 8.5 billion years before the universe completely collapses into a singularity. Given that Homo sapiens have only been around for at most 300,000 years, that gives us plenty of time to relax. Likewise, while it might not necessarily be a comforting thought, it is almost certain that humanity will have been wiped out long before then in any case. Professor Tye says: 'Before the big crunch, at about 5 billion years from now, the sun will use up its fuel and start growing dramatically. 'Its outer layers will expand until they engulf much of the solar system, as it becomes what astronomers call a red giant. Eventually, it fades to a tiny white dwarf. 'To survive, human beings have to move to the edge of our solar system or beyond. We have a few billion years' time to prepare for that trip.' THE BIG BANG THEORY DESCRIBES THE BEGINNING AND EVOLUTION OF THE UNIVERSE The Big Bang Theory is a cosmological model, a theory used to describe the beginning and the evolution of our universe. It says that the universe was in a very hot and dense state before it started to expand 13,7 billion years ago. This theory is based on fundamental observations. In 1920, Hubble observed that the distance between galaxies was increasing everywhere in the universe. This means that galaxies had to be closer to each other in the past. In 1964, Wilson and Penzias discovered the cosmic background radiation, which is a like a fossil of radiation emitted during the beginning of the universe, when it was hot and dense. The cosmic background radiation is observable everywhere in the universe. The composition of the universe - that is, the the number of atoms of different elements - is consistent with the Big Bang Theory. So far, this theory is the only one that can explain why we observe an abundance of primordial elements in the universe.


Metro
10-07-2025
- Metro
'Doomsday' 100-foot mega tsunami likely to hit the US at any moment
Scientists are warning that a 100-foot, Doomsday-style mega tsunami is primed to hit the US West Coast at any moment – and likely within 50 years. On top of that, experts say that the sooner the tsunami hits, the better. The natural disaster threat stems from the Cascadia Subduction Zone, which is a nearly 700-mile fault line from northern California to British Columbia, that has not had much movement in 300 years. That means that the zone is due for a major earthquake, and its effects are predicted to be worse as time goes on. 'By 2100, when climate-driven sea-level rise will compound the hazard, a great earthquake could expand floodplains… more than tripling the flooding exposure of residents, structures, and roads under the high subsidence scenario compared to the 2023 floodplain,' states a recent article published in the Proceedings of the National Academy of Sciences. There is a 37% chance of a quake in the Pacific Northwest happening in the next half-century, and one is almost guaranteed to hit by 2100, according to the study published in April. 'This is going to be a very catastrophic event for the US, for sure,' the study's lead author, Tina Dura, told BBC Science Focus. 'The tsunami is going to come in, and it's going to be devastating.' A quake of magnitude 8.0 to 9.0 could create a 100-foot tsunami capable of crushing eight feet of the coastline and wiping out much of the West Coast. 'After the tsunami comes and eventually recedes, the land is going to persist at lower levels,' Dura said. 'That floodplain footprint is going to be altered for decades or even centuries.' More Trending Such a quake could cause 5,800 deaths, and the resulting tsunami could claim another 8,000 lives, according to the Federal Emergency Management Agency, the nation's agency helping people before, during and after disasters. The coasts of California, Oregon, and Washington, up to northern Vancouver Island in Canada, are under the threat. The last massive earthquake, magnitude 9.0, hit in January 1700 and spurred a tsunami that took out the village of Pachena Bay in British Columbia. 'This study underscores the need to consider combined earthquake and climate impacts in planning for coastal resilience at the Cascadia subduction zone and globally,' states the article. Get in touch with our news team by emailing us at webnews@ For more stories like this, check our news page. MORE: Woman bombarded with hundreds of Amazon packages she never ordered MORE: Urgent recall of Ritz crackers over 'life-threatening' health risk MORE: Mystery after missing paddleboarder's body found in 'unusual' position on secluded lake


The Herald Scotland
10-07-2025
- The Herald Scotland
Are bees deadly? What to know after recent bee attacks
The attack is believed to have been prompted by the presence of Asian hornets, sometimes nicknamed "murder hornets," an invasive species that also has a growing presence in the U.S. The good news is that swarming bee attacks of this severity are rare. Bees and wasps, like plenty of other wildlife, are not known to be particularly aggressive toward humans and generally only attack if their hive has been threatened. While bees and wasps are generally not a risk to people (in fact, their dwindling numbers are a bigger risk to humans as a whole, thanks to the vital role they play in our ecosystem and food chain), stories like the attack out of France are enough to inspire some measure of anxiety. Are bees a potentially deadly danger Americans contend with each time they step out the door? Here's what to know. When bee attacks turn deadly While only an average of 72 Americans died from hornet, wasp and bee stings each year between 2011 and 2021, according to the Centers for Disease Control and Prevention, it can and does happen, especially in the spring and summer months when North American hives tend to be the most active. Several major bee attacks have been reported in multiple U.S. states in 2025 alone. On Sunday, July 7, bees stung members of a crew working on a nursing home roof in Arizona, killing one and seriously harming two others. In May, a 66-year-old Texas man was killed when a swarm of bees stung him enough times to cause his circulatory system to stop functioning properly. Just weeks before, another Texas resident was attacked by a massive throng that killed three of her horses. Why do bees and wasps attack? Generally speaking, bees and wasps aren't aggressive simply for the sake of being aggressive, according to the Cleveland Clinic. Like most creatures with natural predators, bees have developed mechanisms to protect themselves and their nests. If they perceive humans as a threat, whether that be due to swatting them or disturbing their nest, they may sting as a defense mechanism to ward the threat off. Some bees also release a type of "warning" or "danger" pheromone when they sting that attracts other bees to the fight against the perceived threat at hand, like summoning a small insect army. To avoid drawing the ire of a nest, be aware of your surroundings and avoid nests and swatting at bees hanging out nearby, suggests Mayo Clinic. Cover food when eating outside, avoid floral-smelling colognes and perfumes and wear protective clothing like long sleeves and pants when working or playing outdoors. What should you do if you become a target? If you find yourself at the top of a bee or wasp swarm's public enemy list, stay calm and get out of the area quickly. Your best bet is to run to the nearest shelter, suggests an advisory from the University of Arizona, and keep running until you get there. Protect your face, especially your mouth and eyes, by covering the area with whatever you have on hand - a mask, handkerchief, coat, towel, hat or, as a last resort, your shirt could work. Do not try to freeze, play dead or jump into a body of water, the advisory says. When should I go to the ER after a bee or wasp sting? The most common cause of serious illness or death from bee stings is an allergic reaction called anaphylaxis. An anaphylactic reaction affects your skin, airways, stomach and heart, per the Cleveland Clinic. Although this will vary from person to person, initial symptoms are typically characterized by hives, swelling or edema and breathing difficulties. As symptoms progress, you may begin to experience "tightness in the chest, shortness of breath, coughing, wheezing, and then swelling of the face to tongue and lips and eyes," Dr. Payel Gupta, medical director of Allergy, Asthma and Immunology at LifeMD, previously told USA TODAY. If left untreated, anaphylaxis can be fatal. Epinephrine is a life-saving medication used to treat anaphylaxis, and it is injected as a shot in your thigh, according to the Mayo Clinic. Anaphylaxis can happen within seconds, which is why it's so important to call 911 and seek medical care at the onset of symptoms, Gupta said. What if you're not allergic to bees? In some cases, victims of bee attacks can die without having a known allergy, especially if they receive an excessive number of stings. Stings contain venom, which usually can be fought off by the body fairly easily. However, being stung dozens of times can make anyone feel sick as their body works to handle the venom and, in the exceedingly rare case that someone is stung hundreds or even thousands of times, the venom may be enough to cause serious illness or even death, according to the Mayo Clinic. People who are not allergic but have been stung multiple times should still seek medical attention, says the Mayo Clinic, and children or those who have existing respiratory issues are especially at risk for an adverse reaction to a larger number of stings.