FOX31 Denver

Most aggressive dog breeds: Is your pooch on the list?

Sydney Kalich and Nexstar Media Wire

(Credit: Getty Images)

(NewsNation Now) — Smaller, older and male dogs are most likely to growl and be aggressive than other dogs, according to a study of 23 different dog breeds.

Scientists at the University of Helsinki studied the behavior of more than 9,000 dogs to assess aggressive behavior.

  • Purebred collie dog
  • Spanish water dog disposed to work
  • It is a picture os a schnauzer on a grassy field. It is a sunny day with a blue sky on the background.
  • Dogs playing with their owners in the park.
  • Soft-coated Wheaten Terrier standing and looking directly at camera in green grass with yellow flowers meadow. Copy space.
  • A purebred Coton de Tulear dog running without leash outdoors in the nature on a sunny day.
  • Adorable and cute little white German Spitz Mittel puppy dog sitting on the sofa
  • Female pure breed Chinese Crested dog posing outdoors
  • Portrait eines Lagotto Romagnolo Hundes
  • Finnish Lapland
  • Boy Brushing a Shetland Sheepdogs Hair
  • Cute black Staffordshire Bull Terrier dog with his head slightly cocked lying down outside looking at the camera.
  • Man with dog in autumn forest stock photo
  • Smooth collie isolated on a white background
  • Finnish Lapphund lying on snowy road.
  • Dog loves the owner on the coast
  • Cairn Terrier on teeter totter obsdtacle on agility course
  • Welsh Corgi Pembroke puppy take a look, low angle view

Some breeds are more likely to be aggressive, resorting to biting or snapping attacks, than others. The study, published in Scientific Reports, found that Rough Collies were the most aggressive breed. Miniature poodles, miniature schnauzers, German shepherds and Spanish water dogs were also found to be more aggressive.

This graphic was included with the study “Aggressive behaviour is affected by demographic, environmental and behavioural factors in purebred dogs” from researchers at the University of Helsinki, published in Scientific Reports.,

Even-tempered Labrador Retrievers and Golden Retrievers were found to be the least aggressive.

Scientists found male dogs are more aggressive than females, and neutering them has no impact on making them more or less aggressive. In addition to size and sex, the study also looked at age and fearfulness as factors in aggressive behavior.

The study also found that dogs are more likely to be aggressive if they are the owner’s first dog.

You can read the full study below:

NewsNation affiliate KTLA contributed to this report.