Persian Cats And Pugs Have Squished Faces: Here’s The Reason Why
Have you ever noticed that pugs and Persian cats both have adorably squished faces? This isn’t just a coincidence; it’s the result of years of human intervention. Thanks to artificial selection, we now have these cute, furry, flat-faced pets.
A team of scientists at Cornell University and Washington University have determined how intensive breeding has led to “convergence,” a term that refers to unrelated animals and plants developing similar characteristics under similar environmental conditions.
These two species did share a common ancestor once, but they have been evolutionarily separated for 50 million years.
Due to artificial selection from breeding, certain breeds of pugs and Persian cats have converged to the point that they resemble each other more closely than most other dogs or cats.
This phenomenon had not been observed in domesticated species before. For the new study, the researchers measured the skulls of brachycephalic “smushed” dogs and cats.
“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 tilted up in the same way,” said Abby Drake, a co-author of the study and a lecturer from Cornell University.
The same pattern of convergence has happened multiple times within each species. It occurred in bulldog breeds and then separately in Asian dog breeds like Pekingnese and Shih Tzu. The same traits can be seen in cats, specifically the Persian, Himalayan, and Burmese breeds.
With natural selection, convergence shows up in the development of wings in birds, bats, and insects. Usually, it is a sign of a successful trait. But for domesticated species, it can be quite a different story.
The research team mapped the skull shapes, made comparisons, and discovered similarities between them, even though dog and cat ancestors looked completely different.
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Dogs descended from wolves, which are large creatures with long muzzles. Cats descended from wildcats, which are smaller animals with a shorter snout.
“They start off in different places, but because humans applied the same selection pressures, they evolved to look almost identical to each other,” said Drake.
As a species, dogs are more diverse than the entire order of Carnivora, according to the researchers. Cats are also more diverse as a species than the whole family of Felidae.
“We’re seeing this very large evolutionary variation within a species that’s only been evolving for a relatively very short amount of time. 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.”
Sadly, humans have taken it too far with brachycephalic breeds. They are vulnerable to eating, breathing, and birthing issues and would not be able to survive on their own in the wild.
The study was published in PNAS.
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