Foxes Who Live in Cities Are Evolving to Become ‘Similar to Domesticated Dogs,’ Study Finds

(TMU) – Red foxes living in the city are increasingly resembling domesticated dogs due their evolutionary adaptation to urban environments, researchers have found.

Scientists who examined the skulls of over 100 red foxes found that the city-dwelling canines have evolved to have a smaller brain size capacity as well as a wider-shaped snout to help them forage for food better in an urban habitat. Taken together, these “doglike traits” form a potential path to domestication.

Researchers are also finding out that with coronavirus quarantine measures still in effect to varying degrees across the U.K., sightings of red foxes are becoming increasingly common in cities where they have made themselves at home.

The research, published in the Proceedings of the Royal Society Series B, suggests how dogs themselves were historically domesticated over the course of tens of thousands of years of interactions with human beings in environments shaped by our species over the course of time.

“We wondered whether this change in lifestyle was related to adaptive differences between urban and rural populations of red foxes,” said Dr. Kevin Parsons of the University of Glasgow Institute of Biodiversity, Animal Health and Comparative Medicine, who led the study.

“We assessed skulls from hundreds of foxes found within London and the surrounding countryside, and saw that urban foxes had a smaller brain size capacity but also a different snout shape that would help them forage within urban habitats,” he added.

The study would inform researchers of whether the creatures’ adaptation to urban settings and development of different features from their rural counterparts was totally unique, or a process that had occurred in the past.

“It turned out that the way urban and rural foxes differed matched up with a pattern of fox evolution that has occurred over millions of years between species,” Barker said. Continuing, he explained:

“While the amount of change isn’t as big, this showed that this recent evolutionary change in foxes is dependent upon deep-seated tendencies for how foxes can change.

“In other words, these changes were not caused by random mutations having random effects the way many might think evolution occurs.”

The changes conformed to the processed labeled domestication syndrome by Charles Darwin, the founding pioneer of biological evolution.

The Glasgow study builds upon a famous ongoing experiment begun in 1960 by scientists in the former Soviet Union, who managed to turn wild Siberian foxes into tame, doglike canines through selective breeding of less aggressive foxes over the course of a few generations. Eventually, the Russian researchers ended up with foxes who had floppy ears, stubby snouts, and even barked, reports Science.

“I’m not so much surprised as delighted [by the study],” said evolutionary biologist Lee Dugatkin of the University of Louisville, who was not involved with the new work  but has written extensively on the Siberian experiment. “This is a ‘natural experiment’ that is very much in line with what the Russian experiment has found.”

Parsons himself, a Canadian researcher also familiar with the renowned Russian study, had been impressed by the conduct of the city foxes he would see early in the morning on the streets of Glasgow.

“They’d walk by me and stare, as if asking, ‘Why are you looking at me?’” he told Science. “They were fearless.”

The study’s co-author, Dr. Andrew Kitchener of National Museums Scotland, said that the study could also shed light on how dogs evolved to become pets. He explained:

“Human-animal interactions are continuous and some of the basic environmental aspects that may have occurred during the initial phases of domestication for our current pets, like dogs and cats, were probably similar to the conditions in which our urban foxes and other urban animals are living today.

“Adapting to life around humans actually primes some animals for domestication.”