Every Fourth of July, the thunderous crack of my neighbors’ fireworks is quickly followed by the wailing chorus of frightened dogs, including my own two mixed-breed pups. New research suggests Pico’s and Winnie’s sensitivity to noise, especially fireworks, is the most common form of anxiety in pet dogs. The study—the largest ever on canine temperaments—also finds that some breeds are prone to certain anxious behaviors, including aggression, separation anxiety, and fear. The results could help uncover new ways to tackle these traits.
Anecdotes on dog behavior abound, but reliable scientific data are lacking, says Hannes Lohi, a canine geneticist at the University of Helsinki. That’s particularly an issue when looking at problem behaviors that can put dogs at higher risk of being euthanized or winding up in shelters.
So Lohi and colleagues contacted Finnish dog breed clubs and reached out to dog owners around the world through social media, asking owners to rate their dogs’ behavior on seven different anxiety-related traits: noise sensitivity, general fear, fear of heights and surfaces (like reflective tiles), inattention, compulsive behaviors (like relentless chewing or tail chasing), aggression, and separation anxiety. They received more than 13,700 responses representing 264 breeds. To make reliable comparisons, the researchers limited themselves to the 14 breeds with 200 or more surveyed dogs.
In all, 72.5% of all dogs showed at least one anxiety-related behavior, the researchers reveal today in Scientific Reports. Noise sensitivity was the most common across all breeds, affecting 32% of dogs. (Fireworks were the No. 1 cause of noise sensitivity, which tracks with Pico’s and Winnie’s experience.) About 17% of canines were fearful of other dogs, 15% were afraid of strangers, and 11% were scared of new situations. The older the dog, the more sensitive it was to noise—especially thunder.
The researchers also found that certain anxieties clustered in specific breeds. Noise sensitivity was most pronounced in lagotto Romagnolos (a large, fuzzy retriever native to Italy), wheaten terriers, and mixed breed dogs. The most fearful breeds were Spanish water dogs, Shetland dogs, and mixed breeds. And nearly one-tenth of miniature schnauzers were aggressive and fearful toward strangers, but such traits were virtually unheard of in Labrador retrievers. Taken together, Lohi says, the results suggest a genetic component to these anxieties—just as there is in humans.
Previous research backs up a connection between genetics and behavior. For instance, a stretch of DNA in German shepherds codes for the oxytocin receptor gene OXTR. A 2019 study found that gene is associated with sociability—but the same stretch of DNA is also associated with higher noise sensitivity. This same genetic link is likely found in many other breeds, the researchers of that study note. Lohi suggests that by selecting for more social dogs, humans may have unintentionally selected for dogs more sensitive to noise.
If true, it’s “a very cool idea,” says Emma Grigg, an animal behaviorist at the University of California, Davis, who wasn’t involved with the work. She worries that the owners’ self-reports might not be entirely accurate, but, she says, “The sheer volume of the sample may help hedge against bias.”
Dennis Wormald, a dog behavior researcher at the University of Melbourne, adds that some of the study’s findings seem to differ widely from other behavioral studies. For instance, the new study suggests about 17% of dogs show compulsive behavior, which Wormald says “is too high to be believable” based on veterinary reports that suggest true compulsive behavior is relatively rare; meanwhile, the finding that only 4% of dogs have separation anxiety, he says, “sounds far too low.”
Lohi also urges caution in overinterpreting his results. For one thing, he says, the survey asked owners only about the frequency of problem behaviors, not their severity. Another is that the “mixed breed” category didn’t take into account each dog’s unique lineage, nor the fact that mixed breed dogs often grow up in shelters—places associated with high anxiety. In such cases, Lohi says, environment, not genes, might play the starring role.
By identifying which breeds are most likely to display different types of anxiety, Lohi notes, owners can take precautions to give their dogs happier, healthier lives. A prospective dog owner who lives in a bustling city might do better with a breed less sensitive to noise, for example, whereas dogs fearful of strangers might do best in rural, isolated homes.