With their floppy ears, big, soulful eyes, and luxurious fur, Cocker Spaniels are widely regarded as loving and friendly dogs. Unfortunately, research from Spain suggests that the Cocker Spaniel may be more aggressive than other dogs.

Let’s probe the data further to get a better idea of the research around Cocker Spaniel aggression and what it means for the breed.

What Are the World’s Most Aggressive Dog Breeds?

In 2009, researchers at the School of Veterinary Medicine at the Autonomous University of Barcelona conducted a study with data from over 1,000 dog aggression cases logged between 1998 and 2006.¹

Of those cases, English Cocker Spaniels ranked the highest, followed by Rottweilers, Boxers, Yorkshire Terriers, and German Shepherds. The study’s lead author and her team discovered that Cocker Spaniels are more likely to act aggressively toward their owners and strangers. Conversely, the other breeds that showed aggression were more likely to act aggressively toward other dogs rather than people.

The research also goes deeper. Of the Cocker Spaniels, males and Spaniels with a golden color were found to be the most aggressive. The connection with the coat color has to do with the coat pigment, which shares a biochemical pathway with dopamine and other brain chemicals that control aggressive behavior.

Previous research revealed similar findings among male and golden Cocker Spaniels, but this may not be the whole story.

Are Cocker Spaniels Just Aggressive?

Not quite. The authors of the study made it clear that, in most cases, the responsibility for aggression falls on the owners who failed to train their dogs properly. They found that 40% of the aggression in dogs has to do with poor leadership on the part of the owners and a lack of basic obedience training.

Researchers noted that the prevalence of Cocker Spaniels naturally increases the likelihood of not only aggressive behaviors but also reported incidents. There are some differences in the genetic and environmental factors as well, especially if these dogs are bred without consideration for temperament.²

Finally, Cocker Spaniels may be prone to some of the aggression issues that other small, innocuous-looking breeds are,³ such as Chihuahuas and Yorkies. People are more likely to underestimate a toy breed than a Rottweiler or a German Shepherd, which may mean more lax training, fewer boundaries, and possible behavioral issues that escalate to aggression.

What Is Rage Syndrome?

Rage syndrome is a condition that’s often attributed to the English Cocker Spaniel, though it may be present in other breeds. This condition is a genetic disorder that includes outbursts of intense aggression that seem unprovoked.

Typically, dogs with rage syndrome will suddenly freeze, stare, or bite in situations that don’t seem dramatic or intense. These outbursts often occur in otherwise docile dogs, and they seem to have no recollection of the behavior afterward.

Rage syndrome is rare, even in the Spaniel breed. It does occur more often in solid-colored and darker-colored Cocker Spaniels than their counterparts, and most cases occur in solid gold and black Spaniels. Males are also more likely to display rage syndrome.

American Cocker Spaniel vs English Cocker Spaniel

The American Cocker Spaniel and the English Cocker Spaniel are similar breeds and among the most popular in America. Though they share the same early history, they are two distinctive breeds.

In the US, “Cocker Spaniel” is a catch-all term that may apply to the three varieties of Spaniels. But for most people, the Cocker Spaniel is actually the American Cocker Spaniel.

These two breeds have similar histories, lineage, appearance, capabilities, and personalities, but it’s important to note that the aggression studies were specific to the English Cocker Spaniel. It’s not known if the American Cocker Spaniel displays the same possible aggression or rage syndrome as the English variety, but the current evidence doesn’t suggest it.

Final Thoughts: Training Is Key

Though the Cocker Spaniel didn’t come out shining in these studies, that doesn’t mean the breed itself is inherently dangerous. As noted by the researchers, there are other factors at play that may have contributed to the aggression seen in the English Cocker Spaniels.

The color connection may need to be explored more, but both the researchers and fans of the breed note that the Cocker Spaniel is a typically affectionate and loyal breed with proper socialization and training.

• See also: How Good Is a Cocker Spaniel With Cats? Introduction Tips & Tricks

Featured Image Credit: Korvit, Shutterstock