Why do we find ugly animals so attractive? And what makes odd-looking creatures so cute?

Evolution plays a role. According to Austrian zoologist Konrad Lorenz, human attraction to infantile（婴儿的）features, such as big eyes, large heads and soft bodies, is an evolutionary adaptation that helps ensure that adults care for their children, guaranteeing the survival of their species. Strange-looking animals such as blobfish, pugs, aye-ayes and bulldogs all share these infantile qualities that cause an affectionate response among humans and an innate instinct to nurture and protect. And 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.

Ugly animals often have other value—some, 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 their biology might provide fresh insights that could lead to treatments for 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 and can provide enormous benefits to the ecosystems they live in, they often still don't get as much attention as more traditionally cute and cuddly animals. This can result in a bias（偏见）which leads to many of the less attractive species being overlooked in terms of research.

There are culture-led other factors that also drive our obsession（痴迷）with ugly-cute animals. "The ugly-cute thing is very fashionable," says Rowena Packer, a lecturer of animal behavior. This is partly driven by social media, with many celebrities（名人）and influencers showing off pet pugs and French bulldogs on Instagram, she says.

But there are some serious welfare concerns around this trend. Vets are urging people not to choose a flat-faced dog breed, because they suffer from serious health problems. Pugs and French bulldogs which have been selectively bred experience breathing difficulties, repeated skin infections and eye 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.