How to Care for Your New Puppy

How to Stop Fighting in Puppies

Two Young Labrador Puppies Playing in the Grass
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Dog disagreements and aggression not only upset owners, but puppy fighting can also be downright dangerous. You want your new puppy to love other dogs, but sometimes they simply don't. There are a number of reasons for this aggressive behavior and things you can do to negotiate a truce.

Why Do Puppies Fight?

Your dogs aren’t evil, and you're not a bad owner because you have to deal with these problems, according to 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 because of illness or age. This is called status-related aggression. “Most often it’s a junior dog coming up through the ranks,” says Dr. Dodman.

  • Interdog aggression mostly involves dogs of the same gender and occurs four times more often in males than in females.
  • It usually first appears in males 1 to 3 years of age. Castration or neutering decreases the problem in about two-thirds of the cases.
  • Female-to-female aggression more often involves intact females 1 to 3 years old. These fights cause severe injuries and bites. Surprisingly, spaying can actually make the aggression worse.
  • Opposite-sex rivalry seldom happens, but tends to be initiated by the female dog if she's younger, larger, and a more recent addition. Again, injuries can be severe.

Some dogs are abnormal and don't 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.

Signs of Aggressive Behavior in Puppies

It's important that owners 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.
  • The true “top dogs” already know their status and won’t waste time starting a ruckus. They will finish it, however.

Certain gestures or postures from either dog can prompt this type of aggression, says veterinary behaviorist, Dr. Debra F. Horwitz. 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 10- to 12-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 to this, 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.”

Puppies Playing
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How to Stop Aggression

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.

“As long as no serious damage has been done, the very best thing you can do is nothing,” Dr. Dodman says. Dogs generally work things out between themselves within two or three weeks when the wannabe cuts its losses and settles for a lower rank. When they do not, there are actions you can take and a few you should not.

Don't Punish

No matter what type it is or the cause, punishment from the owner makes aggression worse. It's difficult to restrain yourself, but remembering this simple fact is your first step in stopping the behavior.


Dogs who have previously inflicted injuries that required stitches or antibiotics must be prevented from fighting and separated for their own safety.

Step Back From Equality

Preventing dogs from working out their status on their own can turn status-related aggression into Type II aggression, where dangerous injuries take place. You can also inadvertently promote it by trying to treat the dogs equally. “In dog world, you’re up or you’re down, not equal,” says Dr. Dodman.

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 its place early in the process and giving the lower-ranking dog preferential treatment makes matters worse.

This is 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. Ask your veterinarian for a referral to a veterinary behaviorist or consultant, or an experienced trainer. If it has not gone on too long, the aggression may be reversed or at least managed.

Know Your Dogs' Status

Treatment consists of supporting the true top dog while demonstrating to the wannabe that it 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 always keep the dogs separated, they will never learn.

Two dogs playing chase
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Controlled Encounters

Allow supervised encounters, but with both dogs wearing training leads and two people present to control the situation. If an altercation takes place, each person takes a leash and pulls the dogs a foot or so apart. “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,” says Dr. Dodman.

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.

Learn to Predict Fights

Treatment isn’t always this simple and one fight predicts another will occur. These generally take place in the same context or location and often within 24 to 48 hours of the previous incident.

Anticipate and avoid situations that prompt disputes. Prime places for squabbles include hallways where dogs can’t maneuver, doorways, and around “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.