SALT LAKE CITY (ABC4) – Much like how you shouldn’t judge a book by its cover, new scientific insights suggest that you shouldn’t judge a dog by its breed. 

Published on April 29, 2022, a new study led by Kathleen Morrill indicates that breed has much less to do with dog behavior than previously assumed. Their article appeared in Science and has gotten national attention for its surprising findings. 

Morrill’s study surveyed owners of “18,385 purebred and mixed-breed dogs” to track behavioral traits’ correlation to breed. They found that only “9% of behavioral variation” in dogs can be explained by breed. Half of the surveyed dogs were mixed-breed dogs. 

These findings seem to indicate that the previously assumed link between individual dog behavior and ancestral function—what the breed may have been used for historically—is weak. Instead, Morrill suggests that breeds are “distinguished primarily by aesthetic traits.” 

To support their findings, Morill opens their article by saying that “modern dog breeds are less than 160 years old, a blink in evolutionary history compared with the origin of dogs more than 10,000 years ago.” In short, Morill argues that their findings better support the hypothesis that dog breeds share more in common as far as behavioral traits than they do differences; their common ancestry is too ancient to be significantly influenced by modern breeding. 

According to Morill’s data, a dog’s behavior is more likely to be explained by its history, development, and immediate genetics from its parents. 

Morill’s primary conclusion about dog behavior and breed is that “mutts” or mixed-breed dogs are no more likely to have behavioral problems than purebred dogs. The same goes for breeds with bad reputations for temperament and behavior. 

A press release by Best Friends Animal Society, a local Utah advocate for no-kill shelters, says that these findings can help people see that “all dogs are individuals.” They hope that it will increase adoption rates for “large-breed dogs” and mixed-breed dogs. 

Best Friends Animal Society is well known for the “Vicktory Dogs,” Michael Vick’s fighting dogs that were mostly reinstituted to loving homes. “The Vicktory dogs are a prime example of how we should never judge a dog by its looks,” says Julie Castle, CEO of BFAS.