Fact or Fiction: Why Are Small Dogs So Aggressive?

Small dogs are often perceived as more aggressive than larger dogs. Learn which breeds are more likely to bark and bite — and why.

Dogs are still the most popular pet in the U.S. (sorry, cats) and only getting more popular. Just last year, the percentage of homes with at least one dog rose to nearly 45 percent, according to the American Veterinary Medical Association.

For many of these first-time pup parents, smaller breeds may seem the easier or safer option. But looks can be deceiving.

According to numerous studies over the past two decades, certain pint-sized breeds are stubborn as mules and prone to barking, biting, snapping and snarling — while plenty of larger dogs take “man’s best friend” to the extreme. And researchers have some pretty good hypotheses for why.

A 2021 study, conducted by the University of Helsinki and published in Scientific Reports, looked into the factors contributing to aggressive behavior (or a lack of such behavior) in more than ...

Marisa Sloan
Marisa is an assistant editor at Discover. She received her master’s degree in health, environment & science reporting from Northwestern University’s Medill School of Journalism. In a previous life, while earning a chemistry degree from UNC Greensboro, Marisa worked to prolong the therapeutic power of antitumor agents. Ask her about enzymes!
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Fact or Fiction: Why Are Small Dogs So Aggressive?

Small dogs are often perceived as more aggressive than larger dogs. Learn which breeds are more likely to bark and bite — and why.

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