為什麼我們喜歡醜陋的動物？

Every year in California, judges select the winner of the World's Ugliest Dog contest. But why do we have a soft spot for these unattractive animals? A Chinese Crested dog named Rascal once won this contest. Despite their less-than-appealing looks, these pets still manage to tug at our heartstrings. Every June in Petaluma, California, judges examine dogs with squished faces, crooked teeth, bulging eyes, and bristling whiskers to determine the ugliest dog. These dogs often melt the hearts of animal lovers worldwide. Unflattering photos of pets are also a common staple of viral internet content. So why do we find ugly animals so appealing? And what makes odd-looking creatures so cute? Evolution plays a role. According to Austrian zoologist Konrad Lorenz, human attraction to infantile features, such as big eyes, large heads, and soft bodies, is an evolutionary trait that guarantees the survival of their species. These infantile features were coined by Lorenz in 1943. Weird-looking animals such as blobfish, pugs, aye-ayes, and bulldogs all share these infantile qualities that trigger an affectionate response among humans and an innate instinct to nurture and protect. These infantile characteristics increase a person's 'protective behavior, attention, and willingness to care' for the individual and reduce the 'likelihood of aggression towards an infant,' says Marta Borgi, a researcher at the Istituto Superiore di Sanità in Rome, who has studied how baby schema relates to human-animal interaction. In humans, whose young 'depend completely on their caregivers for sustenance and protection, such a response has clear value as it contributes to enhancing offspring's chances of survival,' she says. A 2014 study by Borgi and other researchers found that the concept of 'cuteness' is hard-wired and develops at a very young age, with children as young as three showing a preference for animals and humans with infantile features. 'We showed that the attentive response towards infantile facial traits in dogs and cats emerges very early during our development,' says Borgi. The researchers analyzed the eye movements of children aged three to six and found that they were more focused on images of dogs, cats, and humans that had been digitally modified to give them enhanced infantile traits. They also asked the children to rate the images on a scale of one to five, with one being 'not cute' and five being 'very cute. ' The children ranked round faces with high foreheads, big eyes, and small noses as cuter than those with less infantile traits. Ugly animals often have exaggerated features that are also found in human babies, which scientists believe trigger some of our protective instincts. Some ugly animals, like the blobfish or the naked mole rat, live in extreme environments that they have adapted to in remarkable ways. Scientists are keen to study these animals to understand whether they hold the key to human health conditions such as cancer, heart disease, and neurodegenerative diseases. But while many ugly creatures are exquisitely adapted to their life in the wild, they often still face neglect. This can result in a bias that leads to many of the less attractive species being overlooked in terms of research. There are cultural factors that also drive our obsession with ugly-cute animals. 'The ugly-cute thing is very fashionable,' says Rowena Packer, a lecturer in companion animal behavior and welfare science at the Royal Veterinary College, University of London, in the UK. This is partly driven by social media, with many celebrities and influencers showing off pet pugs and French bulldogs on Instagram, she says. But there are some serious welfare concerns around this trend. Veterinarians are urging people not to choose a brachycephalic, or flat-faced dog breed, because they suffer from serious health problems. Pugs and French bulldogs, which have been selectively bred, experience numerous health issues. A 2022 study concluded that pugs can no longer be considered a typical dog breed as they face such severe health problems. Pugs in the UK are almost twice as likely to suffer from one or more health disorders each year compared to other breeds. In the summer, pugs are also at risk of heat-stroke as they struggle to regulate their body temperature. 'If you think about wolves, they have very long noses,' says Packer. 'They rely upon heat exchange through the nasal passage which allows them to effectively regulate their temperature… they don't sweat like us. ' But pugs have very small nostrils and narrow airways, which makes it difficult for them to breathe and cool their bodies when it is hot. As a result, many pugs make snoring and snorting noises, which people often consider 'cute' and a reflection of the dog's personality, says Packer. 'But this is actually a sign of their obstructed airways. ' Despite their many health problems, pugs remain very popular. According to the Royal Veterinary College, there was a significant increase in pug registrations to the Kennel Club, the UK's national dog register, between 2005-2017. The American Kennel Club lists pugs as one of the most popular breeds. The French Bulldog, another brachycephalic, became the most popular dog in the US by registrations for the first time in 2022. 'There are a lot of psychological barriers which prevent people from accepting the health problems of brachycephalic dogs,' says Packer. 'People like the fact that pugs are very clownish and very lazy and they don't want to see them becoming more moderate by crossing them with other breeds. They're worried that they're not going to be this funny 'couch potato' anymore, even though that is actually the embodiment of the diseases that we're giving them. ' Crossbreeding flat-faced dogs with other breeds is 'really essential,' she says. 'As well as having really extreme phenotypes of body shapes, they also have very low genetic diversity. ' French bulldogs are now the most popular breed in the US, but they can suffer from a range of health problems. Genetic diversity is important as without it harmful traits and diseases can quickly spread through a population and ultimately cause them harm – or even to die out. A 2016 analysis of 102 registered English bulldogs found that they had very low genetic diversity, including in the part of the genome containing genes that regulate normal immune responses. Bulldogs are 'becoming caricatures of their original forms,' says Packer. 'There's a huge trend towards people wanting dogs with very exaggerated skin folding and having little pocket-sized bodies. But actually that reflects malformations with their spine – their vertebrae are now malformed, which can lead to a whole host of neurological diseases. ' So while goofy features such as bulging eyes and wrinkly faces may make us smile, we might want to reconsider our obsession with 'ugly-cute' pets.