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Why are My Dogs Suddenly Fighting?

Updated on May 08, 2013
alexadry profile image

Adrienne Farricelli is a former veterinary hospital assistant and now a certified dog trainer, behavior consultant and author of dog books.

Joined: 8 years agoFollowers: 1,688Articles: 1,256
why are my dogs fighting?
why are my dogs fighting? | Source

What Predisposes Dogs to Fight?

This is one of the biggest problems affecting owners of multiple dogs and sadly one of the most difficult to manage. Two dogs generally getting along well as puppies may suddenly engage into vicious fights as they mature. A younger dog attacking an older dog may suddenly fight despite living in harmony for quite some time. Why is it that way? There are many causes for inter-dog aggression in multi-dog households and these are just a few.

Same-Sex Aggression

If you own two female or two male dogs, fighting is not unusual at all. Some dog breeds are prone to being same-sex aggressive. For instance, Alaskan Malamutes, American Pit Bulls, and Boxers are breeds of dogs known for being same-sex aggressive. According to Nicholas Dodman and Alice Moon Fanelli in an article for Petplace, terriers may be prone to fighting because as a breed they have been developed to work independently. However, any breed of dog, given the right circumstances and predisposition, may develop inter-dog aggression. Generally, these dogs got along well when they are puppies but once the reached social maturity (generally between 12 and 36 months) things dramatically changed and there is an explanation to this.

In nature, it would be quite unnatural for two females dogs or two male dogs close to the same age to live in the same pack. In nature, once the females and males mature, they would leave the pack to form their own pack, or if they would remain in the pack, they would respect the breeding right of the other female or male. According to Gail Fisher a dog trainer, breeder, with over 40 years of experience "A pack with several adult males and females of the same age would rarely, if ever, be found in the wild."

This is further confirmed by the Merk Veterinary Manual " At social maturity, in free-ranging packs, dogs that challenge the established social hierarchy may leave and form their own groups if they do not succeed in altering the extant social order. This situation may be analogous to one form of inter-dog aggression that occurs in multiple-dog households. Social maturity is also the time during which problem aggressions and anxieties develop. In multi-dog groups, the highest-ranking animals may be the only ones to breed".

If the dogs are not spayed or neutered, there may also be a hormonal component to the fights. In female dogs the hormonal changes taking place during the estrus cycle and pregnancy may particularly elicit fights. However, fighting may endure due to hierarchy and breeding rights even when the dog is not in heat or pregnant. Learn more about this in "why are intact females fighting? In male dogs, the hormone testosterone facilitates inter-dog aggression However, once spayed and neutered, dogs prone to inter-dog aggression may no longer fight due to hormones, but they may still viciously fight for other reasons we will see below.

Access to Resources

Social hierarchy is one of the main causes for inter-dog aggression in multi-dog households. According to dog trainer and owner of Peaceable Paw, Pat Miller "Social hierarchies do exist in groups of domesticated dogs and hierarchy can be fluid". By nature, dogs are pretty good conflict solvers, indeed they are masters in ritualized aggression. Ritualized aggression takes place when dogs resolve conflicts without biting. Growling, raising hackles, showing teeth, as dramatic as they are, ultimately help avoid actual confrontations. In nature, spending lots of energy fighting on minor issues is counter-productive as animals must save their energy on more important issues such as hunting and survival. To learn more about this read: Understanding Ritualized Aggression in Dogs

So what causes actual fighting in multi-dog households to take place? Why are dogs biting and actually breaking skin if they are good conflict solvers? Let's take a closer look into hierarchy in dogs. According to Karen Overall, rank is contextually relative. A real high-ranking animal would be normally tolerant of lower-ranking members. The behavior of the lower ranking members towards the higher ranking member is what determines the social hierarchy. In other words, by "withdrawing", lower ranking members make the hierarchical status clear.

Higher ranking members are those who regulate and maintain access to some resources, however, such access is contextual. A certain resource may be highly maintained at certain times when at other times it is not, or other resources may not be maintained at all. Resources, therefore, can be both contextual and subjective. What are some common resources from a dog's perspective? Following are some:

  • Attention from the owner/guests (greeting the owner, interacting with the owner)
  • Food (respect space when feeding dogs, or better, crate the individually for safety)
  • Toys (especially the newer ones or toys that have not been around for some time)
  • Sleeping areas (this could be a favorite bed, a higher spot or a favorite place)
  • Bones (these are seen as high value even among dogs that get along, so practice caution)
  • Space (many dogs have a space threshold, an invisible barrier that if surpassed may yield a dispute)

Generally, a high-ranking dog will maintain access to resource through a ritualized display, however problems start when such displays are not effective. This is why we often see fights in dogs of similar or equal rank, the ritualized displays are ignored just as a soldier refuses to take orders from a captain. At times, ignoring the display is not merely voluntary; it could be the lower-ranking dog ignores the display because it is over-ridden by an event that temporarily blurs the hierarchical status. We will see such circumstance below.

High-Arousal Levels

As mentioned, at times social boundaries can be blurred by events. For instance, if both dogs have not seen the owner for a long time, the lower ranking dog may not defer to the higher-ranking dog's right to access to the owner first because it cannot contain its excitement or it could be he feels the owner will protect him. When over excitement takes place, this is often a trigger for big fights to occur among multi-pack dogs. It is easy for the excitement to blur social rules causing a fight to ignite. At times, when dogs are playing, the high arousal levels may also elicit a fight.

Another example is territorial barking. When two dogs are highly aroused by a trigger seen behind a fence this may elicit a fight. The fight may be caused by re-directed aggression or simply because the higher ranking dog wants to be in control of the boundary (this explains why the higher-ranking dog may mark these areas repeatedly).

In re-directed aggression, the highly aroused dogs go into an hyper-vigilant state that triggers reactive responses which would not take place in a normal setting when the dogs are calm. Because of this possibility, it is always imperative dog owners of dogs who tend to fight to never physically get in the middle of two fighting dogs for the purpose of separating them. With high arousal levels, the dogs are in fight mode and anything between them could trigger a bite, which of course, is not delivered voluntarily. For more about this, visit the ASPCA's Virtual Pet Behaviorist for tips on breaking up a fight.

Changes in the Social Group

A typical scenario affecting social hierarchy takes place when a higher-ranking dog starts becoming weak or old. A younger dog that has reached social maturity may, therefore, ignore the ritualized displays of the older dog which will elicit a serious fight. At times, the senior dog may want to give up top position but is unable to defer in an effective way due to loss of sensory or motor abilities, and this may cause the eruption of serious fights. Because a dog pack in nature cannot be successfully led by a weak member, at times the fights may turn out quite blood and even fatal in some cases.

Another situation where pack changes take place is when a new dog is added to the pack. In such a scenario, the dogs will require some adjustments. Often, fights may ensue, but they can be temporarily until an agreement is found. The way the owner handles the situation may exacerbate the situation. Giving too much attention to the new dog may only create more conflicts. At times, when a dog has been away for some time and is then re-introduced to the pack then there may be some problems as the pack order may need to be re-established.

At other times, dog owners may further exacerbate pack dynamics by intervening. Often, the owners do not have any idea they are creating problems by defending a lower-ranking dog. By protecting a lower-ranking dog and correcting a higher-ranking one, the owner escalates the problem. Dog behavior expert and obedience trainer, Stan Rawlinson, also known as the ''Dog Listener'' suggests dog owners to not fuel the fire by feeling bad and ''rushing to protect the would-be subordinate from being "bullied". This can cause problems and potential fights. Nicholas Dodman calls this form of aggression "alliance aggression" and states it typically occurs when the owner interferes with the establishment of a stable hierarchy.

Poor Social Skills

Not all dogs are blessed with great social skills. If a dog has been poorly socialized, there are chances it may not readily recognize normal social behaviors. These are dogs that feel compelled to attack other dogs for simple things such as panting, wagging their tails or sniffing under tails. These dogs are socially illiterate and must learn the ABC's of normal social language. While some dogs may have been socialized with dogs as puppies, they often forget the language if their inter-dog socialization ends at some point. However, some breeds by nature are not social butterflies, and this must be respected. They may never be happily romping at dog parks but at least they should be able to tolerate walking by dogs without acting aggressively. Learn more about learning social skills in the article:

'How Dogs Lost Their Language'

And what about dog/human interactions?

While a social hierarchy is seen in multi-dog households, it is important to point out that humans are not dogs, and therefore, it is pointless to assume the "alpha role" to earn respect. The dominance myth has been debunked, and the latest studies suggest that dogs are for the most part not status-seeking entities attempting to rule the home, but simply opportunists that will do whatever behaviors are reinforcing to them. For more on this read: Debunking the Dominance Myth

Why Call the Pros

As seen, dog fights are serious issues that can be exacerbated if the owner does not intervene in the correct way. Trying to make the dogs "sort things out" is not recommended. There are countless owners who attempt to "step aside" only to report weeks later their dogs got into a dangerous fight that cost hundreds of dollars of vet bills for stitches. If your dogs are fighting, call a professional, that is a reputable dog trainer well versed in dealing with dog behavioral problems, a veterinary behaviorist or a certified applied animal behaviorist. To read more about why calling a professional is a must when dealing with dogs fighting read: Why a behaviorist is a must for owners of fighting dogs.

Disclaimer: if your dogs are not getting along, make management your top priority and consult with a reputable professional. This article is not to be used as a substitute for professional advice as only a professional can give advice upon assessing and evaluating your dogs in first person. By reading this article you automatically accept this disclaimer.

© Alexadry All Rights Reserved

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    • Clive Donegal profile image

      Clive Donegal 4 years ago from En Route

      I found this article helpful in understanding behaviors I see in our dogs. I am a little less clear on how I might alleviate tension. Young female and adult male pits usually play well together, and when somehing relatively srerious breaks out it usually is over in a minute or two. I am not sure whether I should be doing something to reduce tension.

    • alexadry profile image

      Adrienne Janet Farricelli 4 years ago from USA

      If they are playing there is no need to intervene. When my Rottweilers play it sounds like they are killing each other but it is for the most part drama. If I notice though it escalates a bit too much for my taste I intervene. It helps to train a 'that's enough" command to dogs so they take a little break and then have them start playing again when they are a bit calmer. Here is a helpful hub I wrote a while ago:

    • wetnosedogs profile image

      wetnosedogs 4 years ago from Alabama

      my dogs seem to know "that's enough", but we've had our interesting moments. They all have seemed to learn boundaries and sometimes it's remembering in the excitement of whatever. Great hub.

    • 4mutts 4 years ago

      I have 4 dogs - two females (one pure-blooded Australian cattle dog (ACD) ~13 yrs old and one Great Pyrenees/ACD mix, 7 yrs old) and two males (one Border Collie/ACD, 9 yrs old & one Bernese Mtn dog/wolfhound mix, 7 yrs old). All 4 are fixed. The female pure ACD was a stray that we picked up and could not find a home for. The Bernese mix (the biggest one at 106 lbs) was a rescue. The Border Collie/ACD mix is the dominant dog. We have had multiple bloody fights btwn the females (the pure ACD will not fit into the group and thinks she should be the top dog - she was a breeding dog before we found her but we had her spayed right away) with the smaller ACD having had multiple surgeries to patch her up. We now keep the two females completely separated. Yesterday, the two males (border collie mix & bernese mix) had a little spat - then the female pyrenees mix jumped in and all hell broke loose. My husband managed to get the dogs apart (& luckily did not get hurt) but not before the bernese mix had some pretty bad damage done to his left front leg by the border collie mix. Emergency surgery & $550 later he is home resting. The other two (pyrenees & border collie) were under house arrest and confined to the bedroom or backyard until this evening – though we are still keeping them separate from the injured dog. My husband is convinced that most of the problem is the pyrenees mix and that if she had not gotten involved the squabble would not have escalated as it did. I am planning on looking into a dog behavorist, but we frankly do not have a lot of $$ now and are struggling. Any advice or insight into how we might deal with this is welcome. We think that part of the problem is because we have to keep the 2 females separated and they are jealous of one another (the ACD stays in the kitchen with me while I am working). Are we sending the wrong signal with the punishment for the two dogs that hurt the other and by keeping the 2 females apart? Is it likely that the dominant female (pyrenees mix) is the main problem?

    • alexadry profile image

      Adrienne Janet Farricelli 4 years ago from USA

      I am not sure what you are doing for punishment, but if it's based on aversion (scolding, pinning dog to the ground etc) it wont' help make matters better. All you really can do at this point is keeping the troublemakers separated. I wished I could be more helpful, but I realistically cannot see an easy way out or a safe way to make them all get along. The dog behaviorist route is the best approach in this case as he/she can assess your dog and see the dynamics. I think management at this point may be much easier and safer than attempting something without the aid of a professional that may have a poor success rate with your dogs at stake of getting injured.. Best wishes.

    • kingkos profile image

      kingkos 4 years ago

      I found this article very interesting..i got 4 male dogs now i know why my 2 year old boxer dog suddenly bite my 6 year old shih-tzu..My boxer dog doesn't want any dog come near me. "over protective" And my shih-tzu sometimes when playing with my boxer get angry and they fight.

    • Solaras profile image

      Solaras 3 years ago

      Interesting hub with a lot of good information. I give it a thumbs up. Glad to hear that the Alpha human concept has been debunked!

    • alexadry profile image

      Adrienne Janet Farricelli 3 years ago from USA

      Thank you solaras! It has been debunked by many websites and professionals, but the concept is unfortunately still alive if you google dog dominance, human pack theory and alpha dog:(

    • eerin 4 months ago

      I have two male poodles both are fixed one is my husbands we have been living together for 5 years the dogs have never had a problem. recently my husband's dog who is older is being highly aggressive towards my dog they haveven never fought before. I notice it is only when my husband is not home they never had this issue before what could be going on ?

    • Carla 3 months ago

      I have two rescue dogs one is a female mutt no real predominate breed (per a DNA test) she looks like maybe a Pit/Shepard/Border Collie mix and the other is a male Corgi/Cattle Dog mix. The female is around 5 years and the male is about 2 1/2. All of a sudden the Female started smelling the Male and then attacking them. Prior to this they would play together all the time no problem. Just to add another thing when we walk them, leave them home or if they are just around the house they are fine. The attacks seem random. Not sure what I should do at this point.

    • Amanda 2 months ago

      I have two female mixed terriers from the same litter. They are five years old now and have never had a problem ever with fighting. Have a two year old female English setter and no problems with her in their pack either. This summer we inherited a two year old fixed male chihuahua and had no problems with him either. Now the two sisters are fighting whenever they are in reach of eachother and it's just getting worse. Our setter though younger even steps in-between them to try and stop the fighting. I have read about breeding and packs and age but I am having trouble just getting a straight answer on what can be done to stop this or help with it besides keeping them separated all the time messing up a five year routine.

    • Deb 2 months ago

      I have 5 dogs. 3 are pups of one of the males. The pups are now 3 years old. Yesterday the male pup Max started fighting with his father Kota. This was sudden and has never happen before. Now we can not even have them in the same room. My husband is a disabled vet and we can not afford a trainer. Help anyone.

    • alexadry profile image

      Adrienne Janet Farricelli 2 months ago from USA

      Deb, was it just a "discussion" like a growl with nobody getting hurt, or was there actual biting? If you cannot afford a trainer, your best bet is management, basically simply keep separated, you can get a baby gate

    • ciaraisworried 2 months ago

      I have two older dogs,one large male who is younger ,like 7 or 8,and one medium female like 8 or 9.The male is a lab, and the female is a begale.They don't fight all the time but when they do ,the female is usually left bleeding . I think its over food but I'm not sure what to do about it.I don't want to have to give up the male ,what do I do?

    • alexadry profile image

      Adrienne Janet Farricelli 8 weeks ago from USA

      Separation, use baby gates to separate the fighting parties or find a trainer/ behavior consultant using positive training methods/behavior modification to help you out.

    • Lisa 7 weeks ago

      I have 3 Frenchbull dogs,the Dad,the Mum and we kept one of their puppies ,little boy. He is 16 months old . Most days it's peace and calm in the house but occasionally Dad and son fight for stupid reasons,we have to dive in and separate them ,sometimes they have little cuts on them and it's very distressing when it happens .after they trott of together and cuddle up and sleep . I hate it when it happened,they have both been neutered and so has the mum . Any ideas how to stop ,I've been trying to read the signs but it just happens !

    • alexadry profile image

      Adrienne Janet Farricelli 7 weeks ago from USA

      Lisa, can you describe the "stupid reasons" that triggers their fighting? It might be helpful from a management standpoint.

    • Lisa 7 weeks ago

      Feeding time was the biggest ,so we feed in different rooms but the silly things could be a toy,my son walking through the door ,just silly things . Sometimes I know and I can stop it and it's fine other time you just don't and it's the big one. Thankyou for getting back to me .

    • alexadry profile image

      Adrienne Janet Farricelli 6 weeks ago from USA

      You can try some different things but it really be ideal to have a behavior consultant guide you through. Feeding in different rooms is great management plan. When your son comes in the door try keeping both on leash, you have one, somebody has the other, keep them at a distance from each other, if they get show any small sign of conflict, son goes out the door. If they are calm, son enters and ignores them. With him ignoring them, the dogs will figure it out there's nothing to fight over. Keep rehearing this over and over several times a day. Dogs should also be trained to respond to an interrupter sign that you can use that tells the dog to stop the beginning of a squabble in its tracks and that means to come to you. This should all be trained with a trainer as it requires several rehearsals and for safety.

    • Nat 5 weeks ago

      I've got a 2 y/o Rottweiler who has suddenly started showing signs of aggression. He recently attacked a staffie that had been growling/nipping and mounting the other dogs at the park. I don’t feel as if it was an 'aggressive attack', rather he was trying to tell the staffie off for growling and dominating the other dogs (my dog pulled him off and then dragged him away). However the other dog needed quite a few stitches so I’m by no means trying to say we weren't at fault. He has also started showing fear toward strangers who approach us and will growl at them. We got our dog as a puppy, and he has been thoroughly socialised from the get-go. Do you have any thoughts on what this sudden change in behaviour could be due to? Obviously we are getting professional help from a trainer as well. I was always so proud of our Rottie for changing peoples negative perception of the breed! We have worked so hard to keep him socialised and well-trained but his behaviour lately is so worrying.

    • Wendy 5 weeks ago

      We have a total of four dogs in our home, a min pin, a dachshund mix, a beagle mix, and a golden retriever. Recently our golden and our beagle have began fighting. They have lived together for over 5 years together and we have never had any problems.

      The first fight appeared to have broken out over a new sleeping area, we were awakened by the sound if them fighting late at night. We were able to stop the fight but our beagle ended up with a small puncture wound to her ear. Thinking it was a one time thing, we closed off the closet they were attempting to sleep in, separated the dogs for the night, and they seemed to be OK the next day. I had been at work but my son said they gotten along just fine. Until...I got home from work. I came in the door and all dogs came very excited to greet me as usual and again a fight broke out between the same two dogs. Again our beagle ended up with a couple of small wounds. Our beagle has always had a little more of an aggressive personality, but our golden has never shown aggression at any time. Though they appear to be getting along fine now, its only been a couple of days since the fighting. I'm afraid that my tension and worry may cause them to be aggressive with each other again. Is it possible that this is an isolated occurance?

    • alexadry profile image

      Adrienne Janet Farricelli 5 weeks ago from USA

      Nat you need to take action before the behaviors you are seeing put roots. At 2 years old, Rottweilers are in full doggy adolescence, They start becoming discriminative on who to befriend and are no longer the puppies that got along with each other as in the past months. At this age, they are more serious and may no longer tolerate certain behaviors of other dogs. No more dog park but if you know some pals he gets along with that aren't into mounting or engaging in bully behaviors, have some play time with them under a controlled setting. Rotties are always blamed at the dog park no matter what and puts them in a bad light. About the growling of others, it's hard to say what may have started it, but you can work on it, by finding a trainer who uses positive training techniques based on countercondiitoinng and desensitization. My boy also went through a period like that, when he was 2 and a half, never growled at people but then after a stressful period (a move) he started doing that, but we nipped it in the bud before it established. If you look up my profile, my pinterest account Daily Dog Discoveries it has a dog aggression category with all my hubs and lots of tips. Best of luck!

    • alexadry profile image

      Adrienne Janet Farricelli 5 weeks ago from USA

      Generally, aggressive behaviors do not tend to stop once they have started, unless early intervention is taken. It sounds like there is some competition going on over your presence, which may start from the arousal of greeting you and then spills out to aggressive displays. Sounds like sleeping areas are also culprits. Unfortunately, these things are apt to happen when housing several dogs in the home. Why they have gotten along well for 5 year and now they are fighting may be not easy to comprehend, but sometimes if a dog is getting older he/she may not be able to communicate as well as before. This assuming one dogs is getting old.. You will need a professional to come take a look and gather a history of your dogs and plan something out, but in most cases, keeping the two parties separated is the best and safest option.

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