How to Care for Your New Puppy

Puppy Aggression: Why Dogs Fight

Status Related Aggression and Dealing With Puppy Fighting

Two Young Labrador Puppies Playing in the Grass
Martial Colomb/Photodisc/Getty Images

Doggy disagreements and puppy aggression not only upset owners, puppy fighting can be downright dangerous. We want our new puppy to love other dogs, but what happens if they don’t? Why do some dogs argue, and how can owners negotiate a truce?

Your dogs aren’t evil and you are not a bad owner because you must deal with these problems, says Dr. Nicholas Dodman, a veterinary behaviorist at Tufts University.

Snarls may erupt when a new puppy arrives in the household, or when a top dog becomes infirm with illness or age. This is called status-related aggression, says Dr. Dodman. “Most often it’s a junior dog coming up through the ranks,” says Dr. Dodman.

Interdog aggression mostly involves the same gender and occurs four times more often in males than in females. It usually first appears in males one to three years of age. Castration decreases the problem in about two-thirds of the cases.

Female-female aggression more often involves intact females one to three years old. These fights cause severe injuries and bites, and spaying can make the aggression worse.

Opposite sex rivalry seldom happens, but tends to be initiated by the female dog. She’s usually a younger, larger, more recent addition. Again, injuries can be severe.

Recognizing Aggressive Behavior 

Learn to recognize how puppies communicate. Dogs challenge each other with stares, shoulder or hip bumps and shoves, mounting behavior, or blocking access to food, play, or attention. Less secure dogs tend to bark, growl, snarl and try to bite, while the true “top dogs” already know their status and won’t waste time starting a ruckus--but they will finish it.

Certain gestures or postures from either dog can prompt this type of aggression, says Dr. Debra F. Horwitz, a veterinary behaviorist, and president-elect of the American College of Veterinary Behaviorists. Body language challenges include placing their head or paws on the back of the other dog, direct eye contact, and/or a high tail and stiff legged approach.

“In a normal interaction, if one dog responded with subordinate body postures or cues, the encounter should end peacefully,” says Dr. Horwitz. But things can quickly get out of hand if one dog refuses to recognize and appropriately respond to these social cues.

Status-related aggression (also called Type I) occurs most commonly in middle management dogs. “The aggressor oftentimes is the underdog, it’s the wannabe,” says Dr. Dodman. “A ten to twelve-month-old puppy starts to feel his oats and becomes pushy with the other dog and gets put in his place. Dogs that break dog rules will be subject to dog discipline.” Puppy owners may call this jealous behavior or sibling rivalry.

Dr. Dodman believes terrier breeds may be more prone, but it’s not exclusive to them. “Terriers are feisty and tough, they refuse to take no for an answer, and won’t lie down when they’re dead,” he says. “But one of the least important factors is size. Little dogs don’t know they’re little dogs, you’d have to write them a letter to explain.”

Fights can be noisy and sound terrifying but most dogs know how to fight without hurting each other. Battles typically include lots of neck wrestling, open mouth biting, and raised hackles. One or both dogs may get nicked with a tooth through an ear or lip. This can be bloody, but rarely serious, says Dr. Dodman.

“As long as no serious damage has been done, the very best thing you can do is--nothing,” he says. Dogs generally work things out between themselves within two or three weeks when the wannabe cuts his losses and settles for a lower rank.

When Aggression Turns Dangerous

Punishment makes aggression worse. Also, preventing dogs from working out their status on their own can turn status-related aggression into Type II aggression, where dangerous injuries take place. Dogs that have previously inflicted injuries that require stitches or antibiotic must be prevented from fighting and separated for their own safety.

Owners can cause Type II aggression by giving support and encouragement to the wrong dog. Preventing the true top dog from putting the wannabe in his place early in the process, and/or giving the lower-ranking dog preferential treatment--or trying to treat both dogs equally--makes matters worse. “Equality ain’t dog world,” says Dr. Dodman. “In dog world you’re up or you’re down, not equal.”

It’s most common between two female dogs who typically get along fine when they’re alone. “But the minute the owner walks back in the house all hell breaks loose,” says Dr. Dodman. This type of aggression requires professional help so ask your veterinarian for referral to a veterinary behaviorist or consultant, or an experienced trainer. If it’s not gone on too long, the aggression may be reversed or at least managed.

Defusing and Preventing Aggression 

Treatment consists of supporting the true top dog while demonstrating to the wannabe he won’t receive help from the owner. How do you determine the dogs’ rankings? “In 95 percent of cases, the older and incumbent dog is the alpha,” says Dr. Dodman. These dogs generally exhibit confidence. They eat first, go through doors first, act more independent and require less attention from the owner.

“The needy dog wants to spend all the time with owners, paws at mum’s skirt, wants to be on the lap, shivers, and shakes--that’s a beta,” says Dr. Dodman. He recommends an initial six-week program that removes owner support from the wannabe while making the true top dog “first” and favored in everything. The top dog gets greeted first, toys first, and into and out of the door first even if you must tie the wannabe to a fence. “If anybody must be crated when you go out, it’s the beta,” he explains. “Privilege always goes to the alpha.”

Make sure this preferential treatment takes place within sight of the beta, too. If you keep the dogs always separated, they will never learn. Allow supervised encounters, but with both dogs wearing training leads. “If an altercation takes place, the husband takes one dog’s line and the wife takes the other and pulls the dogs about a foot apart,” he says. “Let them yell and spit and fight and flail at each other while you hold them back and they can’t get at each other.”

Once the dogs quit with exhaustion, crate or tie the underdog to an immovable object. “Then both owners must make a huge fuss over the alpha in front of the beta,” says Dr. Dodman. Dogs read body language and must understand which dog won and which lost the fight. Leave the wannabe crated for twenty minutes before trying again--with both dogs still on leads. “If they go at it again you repeat the lesson,” he says.

Treatment isn’t always this simple. One fight predicts another will occur and these generally take place in the same context or location and often within 24-48 hours of the previous incident. Anticipate and avoid situations that prompt squabbles. Prime places for squabbles include hallways where dogs can’t maneuver, doorways, and “owned” items such as a preferred resting spot on the sofa.

“We can pour oil on the troubled waters with medication like Prozac,” says Dr. Dodman. “It decreases aggression, and increases dominance, so sometimes I treat the aggressor because I want to decrease aggression, and sometimes I treat both dogs.” Ask your veterinarian if medical intervention may help your dogs.

Some dogs are abnormal and do not signal or respond appropriately to other dogs. They may simply be wired wrong. But understanding the realities of “dog world” can help you build a peaceable kingdom for all your furry family.