Breeding for “cute” is to make dogs and cats look more similar

Convergent “cute” means that dogs and cats look the same

By Rachel Nuwar Edited by Allison Parshall

What do Persian cats, peking dogs, and pugs have in common? They all share a dramatically distorted skull, with a flat, round face and nose pushed up between the eyes. This unnatural form is the product of decades or centuries of artificial choice to make animals of our pedigree more similar to the intrinsic cuteness of human babies.

These varieties are morphologically extreme. In fact, cats and dogs with these characteristics have skulls that resemble each other than their own wild ancestors. According to new research in Proceedings of the National Academy of Sciences.

“Wolves and wild cats have completely different skull shapes, but by applying them [selective breeding] “We’ve seen a lot of people who have had a lot of fun,” said Jonathan Rossos, an evolutionary biologist at Washington University in St. Louis.

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Dogs and cats with round flat faces – technically called braxephalic from the Greek for “short head” – present an unusual example of convergent evolution that occurs when species evolve independently as they become similar to each other in the face of the same selective pressure. This process is usually driven by natural selection. For example, birds and bats have evolved to fly, and associated marine animals continue to evolve like crabs. However, in the case of Brachycephalic cats and dogs, it is caused by selective breeding to accommodate human preferences for red devotional traits, such as round, flat faces with high noses.

“These are all new forms of skull that humans only came about for what they want to see in their companion animals,” says Abby Grace Drake, an evolutionary biologist at Cornell University.

But it comes with human preferences Results of Sub-Branch Kidney Animals Related– Could not survive in the wild. “We breed them cutely, and this has led to a very scary health issue for them,” says Drake. Pets like Persians and pugs often need orthodontic surgery, for example, because they are extremely difficult to breathe, and often suffer from eye, teeth and nervous system problems. They are also intolerant of heat and exercise due to lack of proper oxygen.

Drake, Rossos and their co-authors were originally set out to understand the diversity of the shapes of cats and dogs. They collected 1,810 animals skull measurements from a variety of sources, including computerized tomography (CT) scans of pets at the veterinary hospital and specimens at the Natural History Museum. Their samples included 148 domestic cats and 677 domestic dogs, including both purebred and mixed breeds. Of the dogs, they categorized eight breeds as highly arm-phase: Boston Terrier, Brussels Griffon, English Bulldog, French Bulldog, Japanese Chin, Pekiki’s, Pug, and Sheese Tsi. For cats, Persians, Himalayans and Burmese, it fell into that category. The team also collected data from dozens of wild species, representing the majority of the Canidae and Scallop family, to which their dogs and cats belong, respectively.

To directly compare animals, the team created a three-dimensional model of each skull, and notably created points that were anatomically similar to them across species and breeding. Researchers have discovered that the shape of the skulls of late-arm animals is different from those that evolved in nature. Whether cats or dogs, these breeds embraced similarities with one another in their skull structure than their wild ancestors. Specifically, the palate is tilted, significantly reducing the nasal area and limiting the airway and back of the throat. Some Persian cats actually lacked a completely nose bone.

“People talk about things that take millions of years to evolve,” Drake says. “However, sequestering gene pools with inbreeding and enforcing large selection pressures can produce an incredible amount of diversity in a short period of time.” While this is appealing from an evolutionary biology perspective, she and her colleagues stress that they do not consider it worthy of health effects for animals. Rossos agrees that “animal welfare should be our number one priority.”

One future question for researchers to investigate is the fundamental genetics of Brachyphalic characteristics, he adds. Some evidence suggests that pet dogs and cats each carry different genes associated with the upper arm ball. “It certainly appeals to learn more about genetics,” says Rossos.

Heather Lorimer, a geneticist at Youngstown State University, was not involved in the study, but agrees that scientists would agree that it is worthwhile for them to investigate the genetics behind the characteristics of Xu-phasic compatibility.

“It may be possible to start with such a careful and descriptive paper and stay home with individual developmental regulatory genes that affect specific skull structural elements,” says Lorimer. “This can lead to understanding very specific changes that can lead to health issues.

But for those looking for a healthy pet who hasn’t contributed to welfare issues, Drake has some simple advice. Obtain mixed animals from the shelter.