Are Small Dogs Really More Aggressive? Find Out!

In 2022, the percentage of U.S. homes with at least one dog residing within rose to nearly 45 percent, according to the American Veterinary Medical Association. The sourcebook they provide is filled with all sorts of interesting information shedding more light on our affinity for animals.

While dog owners continue to outnumber feline owners, the breeds we’re drawn to are all over the map when it comes to the size, age, and temperament of the doggos we choose. Smaller breeds can seem like the wiser choice for many but looks can be incredibly deceiving.

According to several studies conducted over the past 20 years, some pint-sized breeds are as pigheaded as donkeys and prone to such pesky behaviors as constant barking, nipping, snapping, and snarling, and researchers have some pretty good theories as to why they’re so tenacious.

Most & Least Aggressive Dog Breeds

In a 2021 study conducted by the University of Helsinki and published in Scientific Reports, scientists looked into the contributing factors behind aggressive behavior (or a lack of) in approximately 9,200 purebred dogs. They discovered that small dogs do, indeed, have significantly higher odds of aggression as compared to their medium- and large-sized peers.

Among the most aggressive breeds on the list they comprised were miniature poodles (no surprise there) and miniature schnauzers. They also determined that Labrador retrievers and golden retrievers were among the least aggressive (another non-shocker) pets.

Another canine study undertaken published in Applied Animal Behaviour Science in 2008 also endeavored to determine which breeds were the most aggressive. The researchers polled the owners of more than 30 dog breeds to get to the bottom of this frequently-posed question.

According to the study’s results, Chihuahuas, dachshunds, and Jack Russells are the most likely breeds to attempt to bite people. They also learned that more than a fifth of Jack Russell terriers displayed intense aggression toward dogs they weren’t familiar with.

Why Are Small Dogs So Aggressive?

The answer is one that veterinarians, trainers, and animal behaviorists have been saying for years: it’s generally the owner or paw parent’s fault. Researchers concluded that pet owners of small breeds tend to be far more lenient when correcting bad behavior — if they do at all.

As a result, smaller dogs tend to have less social skills and are less obedient on average. Let’s face it, they rule the roost at home and get pretty much whatever they want due to their adorably diminutive size.

Genetic Makeup

Could it also be in their genes? Perhaps. Some researchers believe that toy and small dog breeds today are as aggressive as they are because for centuries human beings not only encouraged their behavior by ignoring their antics but they didn’t bother to breed these traits out during the domestication process. Let’s face it: small, cute, and cuddly equals getting cut a lot of slack in life.

To support this notion, a 2016 study published in BMC Genomics, mapped the genomes of hundreds of dog breeds searching for genetic indicators connected to fear and aggression. As expected, their findings identified a link between aggression and a growth factor gene giving small dogs their miniature size.

Pint-Sized Pride or Scared Witless?

Some people wonder whether it’s akin to small-man’s syndrome or the fact they’re more vulnerable than bigger dogs so they have more to fear. Because of this, little dogs are quicker to react and go on the defense.

The 2021 University of Helsinki study referenced earlier noted that “highly fearful dogs had over five times higher odds of aggressive behavior than non-fearful dogs.” Small dogs, when compared with larger canines, also tend to have more issues with separation anxiety, excitability, and hyperactivity in connection to their owners’ departure and return.

VCA Animal Hospitals recommends meeting with a veterinarian or even a board-certified veterinary behaviorist if you recognize any of these negative behaviors in your pet.