15 Dog Breeds More Likely To Show Aggression Without Proper Training

Some dog breeds may show aggression under certain conditions—not out of malice, but due to strong instincts, lack of socialization, or insufficient training. While the majority of dogs are loving companions, these 15 breeds have been statistically shown to bite their owners more often, particularly when not properly guided. Knowing the risks is key to being a responsible and safe dog owner.

Chihuahua

Small but surprisingly feisty, Chihuahuas rank high in studies on owner-directed aggression. The dog’s territorial nature and intense loyalty to one person can turn into nipping or biting when they feel threatened or ignored. A 2008 University of Pennsylvania study placed them among the top breeds for human-directed attacks despite their size.

Chow Chow

Chow Chows have a dignified and independent nature, often forming deep attachments to a single owner while remaining distant from others, including family members. Their dominant streak makes early socialization vital, as their protective instincts can turn into territorial aggression. Without proper training, they may exhibit defensive behaviors, making them wary of unfamiliar people and pets. 

Dachshund

Despite its size, Dachshunds show surprisingly high levels of aggression toward both strangers and owners. A study by the University of Pennsylvania found that one in five had bitten or attempted to bite their owner. The Dachshund’s bold nature, originally bred for badger hunting, makes them react strongly to perceived threats.

Presa Canario

The breed was involved in a highly publicized fatal attack in San Francisco in 2001, raising alarms about ownership risks. Originally bred for guarding and fighting, the Presa Canario is powerful and difficult to handle without firm, experienced training. Inadequate control or inconsistent discipline can lead to conflict behavior. 

Akita Inu

Akitas are known for intense loyalty, but that devotion can manifest as suspicion or hostility toward others, even within the household. This breed’s stubbornness and strong prey drive require rigorous training from an early age. Japan classifies the Akita as a national treasure, yet it enforces strict ownership laws due to attack incidents.

Rottweiler

Rottweilers possess strong protective instincts that can turn dangerous if mishandled. Their loyalty makes them excellent guardians, but poor socialization or harsh training can lead to possessive attitudes, even toward family members. Early positive reinforcement and consistent leadership are essential to shaping a balanced, well-behaved Rottweiler. 

Jack Russell Terrier

Behavioral studies have shown this dog to exhibit more owner-directed snapping and biting than most larger breeds, especially when frustrated or under-stimulated. Intense energy and a dominant personality make Jack Russells prone to challenging their owners. They’re quick to assert control if not given consistent rules and leadership.

Alaskan Malamute

In several North American regions, Malamutes are classified as high-risk dogs due to documented cases of hostility. Although loyal and hardworking, Malamutes can become unruly or aggressive without structured training and regular exercise. Their pack mentality makes them prone to dominance struggles with owners who fail to assert clear authority. 

Cocker Spaniel

Though mostly gentle with floppy ears and soft eyes, some Cocker Spaniels have a well-documented issue known as “rage syndrome.” This rare condition affects about 4% of solid-colored Spaniels and causes sudden, unprovoked attacks toward familiar people. Studies have noted a genetic link in solid-colored Cockers, particularly reds and golds, which are more prone to this disorder.

Belgian Malinois

Widely used in military and police work, the Belgian Malinois is not a typical family pet. If not given intense mental stimulation and daily work, they can become hyper-reactive and even hostile. Inexperienced owners often report bites during routine handling, prompting some dog trainers to classify them as “handler-aggressive” without proper structure.

Dalmatian

Bred to defend horses and carriages, the Dalmatian developed instincts that make it naturally protective. Without proper socialization, they may develop distrust, even toward family members. Additionally, some bloodlines carry a genetic predisposition to aggression and hearing loss, both of which can lead to unpredictable reactions when startled.

Weimaraner

Behavioral surveys have recorded a higher-than-average rate of fear-based attacks in this breed, especially in homes without firm boundaries. Velcro-like attachment to their owners can turn into severe separation anxiety in Weimaraners, often triggering destructive or aggressive behavior. First developed for hunting large game, they require constant engagement.

American Bulldog

Although affectionate when properly trained, American Bulldogs are prone to assertive behavior and require experienced handling. If owners show inconsistency or fear, these dogs may challenge authority, even physically. In 2023, multiple U.S. municipalities proposed breed-specific legislation after a sharp rise in owner-related bite incidents involving Bulldogs.

German Shepherd

Among the smartest working breeds, German Shepherds excel in law enforcement and protection, but they’re not risk-free. Without firm, consistent leadership, their loyalty can warp into possessiveness. Harsh corrections or erratic training often backfire, leading to redirected hostility toward handlers. Several insurance companies have placed them on restricted dog breed lists due to bite incidents.

Siberian Husky

Huskies are independent, intelligent, and packed with energy—traits that can become defiance or aggression without firm training. Bred to pull sleds across vast distances, they require constant stimulation and strong leadership. Their powerful prey drive has led to documented attacks on cats, livestock, and, in extremely rare cases, children in domestic settings.