Did your dog suddenly turn to you aggressively with no warning at all? Many different factors can impact canine behavior. Some are more obvious than others, so it’s important to understand what may be causing the behavioral change.
Advertisement
Aggression in dogs is not something to take lightly. Not only is this a concerning behavior for dogs in general, but it is especially worrisome in a pup that is usually friendly. So, what could cause a dog to suddenly turn aggressive toward you or other dogs?
To address and change the behavior, you must understand why it’s happening. In this article, we’ll discuss the details of canine aggression in our furry friends and help you understand why your pup is experiencing this sudden change in temperament.
Things To Know About Sudden Canine Aggression
Aggression can be triggered by many different environmental factors. Aggression is not generally prompted by a desire to hurt and might be a reaction to an environmental trigger. This includes a dog being afraid, showing possessiveness, testing limits, being in pain, aging or having an underlying medical condition. Sudden changes in a pup’s home environment or routine can also trigger aggressive behavior. Additionally, some breeds are more prone to aggression than others.
It is important to pay attention to even small signs of aggression. Seek out help from your veterinarian, as well as an animal behavior expert, if things start to get out of hand or you cannot determine the underlying cause of the aggression. Always be careful when introducing new pets or people, especially if your pup has been acting out and showing signs of aggression. Proceed with caution if your dog is acting aggressively, even with only small signs. You do not want to get bitten or for anyone else, including your pup, to get hurt.
Signs Of Aggression
Before we discuss the details of this sudden behavior in dogs, it’s important to understand what aggression can look like in our furry friends. Aggressive behavior is quite different from mouthing or biting behavior. Some dogs can experience mild grumpiness from time to time, which is not always a major cause for concern. So, what are the signs of actual aggression in dogs?
The Most Common Signs Of Aggression In Dogs Include:
- Tense or rigid posture
- Intense stare
- Hackles raised
- Growling
- Showing their teeth
- Muzzle punch, which involves the dog hitting you or others with their nose
- Deep bark that sounds more threatening than usual
- Snapping
- Growling or guarding objects
- Bites ranging in intensity
- Biting and retreating
- Biting and continuing to attack
While this is not always the case, most dogs show some warning signs before they bite. These warning signs are often one of the many different ways a dog may be trying to communicate. Some dogs may turn to destructive behavior by digging up the yard or stress-induced yawning to let you know they are unhappy, but aggressive warning signs look entirely different.
Many dog owners label their dog’s aggressive behavior as “sudden” or “unexpected,” when really, they are missing many clues leading up to the action. The best way to stay informed on canine aggression is to educate yourself on the many possible signs. Staying informed can help keep those in your home safe, as well as prevent negative interactions with other animals.
Types Of Canine Aggression
Before diving into the most common causes of sudden aggression, let’s first discuss the types of canine aggression you may see in your furry friend. Multiple examples of aggressive behavior can stem from these categories, making it important to understand the fundamentals.
- Protective/Maternal Aggression: Aggressive behavior that stems from protecting their offspring or puppies, often coming from a female.
- Territorial Aggression: Aggressive behavior directed toward an animal or person that is entering their territory. Their territory can include their home, their yard, or any other space your dog claims to be their own.
- Predatory Aggression: Aggressive actions are directed toward other animals that they are interested in hunting. This aggression can be tied to a dog’s prey drive and often results in a deadly strike.
- Fear Aggression: Aggressive behavior that is fear or anxiety-based. This behavior can involve fear in new situations, environments, or meeting new people. This behavior is often due to an animal feeling cornered or trapped by its current surroundings.
- Sexual Aggression: Aggression that is tied to mating behavior. This behavior is directed toward the animal they are mating with or other dogs that seem like a competition.
7 Reasons For Sudden Canine Aggression
Now that you understand what canine aggression can stem from, it is time to discuss the seven most common reasons behind sudden aggression in our beloved companions. Ranging from protecting their favorite toys to feeling unwell, your dog’s aggression could be pointing to something more!
Being Possessive
Possessive aggression is one of the most common forms of canine aggression that pet owners experience. Possessiveness, or resource guarding, involves a dog guarding a specific object they claim as their own and becoming aggressive when anyone approaches it. This aggression can happen when an owner tries to take this object away or even when a person or animal approaches the area.
Not only can this occur when a dog is guarding their food or a favorite toy, but it can also happen when strangers enter their home. Dogs can become extremely possessive over their space, causing them to display aggressive behavior if they feel like their territory is being invaded. If aggressive behavior occurs when he is trying to guard a resource, it is likely due to possessive aggression.
Redirected Aggression
Redirected aggression is another common form of canine aggression. Redirected aggression involves a dog becoming stimulated by a specific trigger, only to be interrupted by something or someone in the process. This trigger causes a dog to redirect its aggression away from the original trigger and turn it onto the person or animal that interrupted them. This reason is why it is so important never to interrupt a dog fight with your bare hands.
For example, many pet owners will receive severe wounds when de-escalating a dog fight. The owners often reach for their dogs to separate them, only to have one of the dogs turn around and suddenly bite them. This aggression can occur in otherwise friendly animals and dogs of any age or sex.
Pushing Their Limits
Pushing a dog to the point of frustration can lead to aggression in some of our canine friends. Many dogs have limits to specific behavior they can tolerate and may become aggressive if those boundaries are pushed. Just like you and I may not tolerate repeated action over time, our dogs are the same way.
For example, many dogs will offer a few warning signs to show their frustration with a current scenario. A dog may snarl and growl at a child tugging their ear, only to become overwhelmed if their warning signs are not understood. Pushing a dog’s limits may cause them to become aggressive, often leading to bites and injury. If your dog is not left alone as their frustration rises, his boundaries may be pushed, causing this aggressive reaction.
Pain
Pain can cause a dog to behave in many abnormal ways. Discomfort can decrease their tolerance in multiple situations, causing them to become aggressive in some cases. Not only does pain hurt, but it can be extremely stressful for a dog to handle. This is especially true if it’s due to an acute injury or illness. A dog may become aggressive when the painful area is touched or experience aggression due to a buildup of stress.
Identifying why a dog is in pain can be tricky. Pain in dogs can be due to joint conditions, lacerations, injured limbs, GI conditions, back injuries, and more. If you think your dog is experiencing a painful episode that triggered this aggression, it’s best to contact your veterinarian for further care.
New Medical Conditions
A new medical condition can be extremely stressful for a dog to handle. Medical conditions can trigger sudden canine aggression, especially if it leads to changes in daily routine. Not only can the onset of new symptoms lead to heightened anxiety, but a change in their structure can further aggravate a stressed-out pup. A change in routine can involve new daily medications, more trips to the vet, and any decline in their overall health.
The onset of a new medical condition can lead to new canine aggression but may even provoke hostility in an already grumpy dog. If you think your dog’s sudden aggression is tied to a new medical diagnosis, we suggest speaking with your vet about ways to offer comfort.
Changes In Their Environment
Many dogs thrive in a structured environment. Our canine companions find comfort in a general routine, leading to stress if there are any sudden changes in their life. A stressed-out dog is more likely to snap in certain situations, opening up the door for behavioral changes. Major shifts at home can cause a dog to react in ways it wouldn’t have before and may even display aggressive behavior as a result.
Dogs can experience stress due to switching homes, the sudden absence of an owner, new people in the home, new pets in the home, and more. If your dog’s aggressive behavior began after a change in their routine, this could be the cause of their aggression.
Aging
While age is not a disease in itself, it can bring many life changes. A senior dog is more likely to experience chronic pain, new medical conditions, and even heightened stress due to environmental changes. Each of these complications can lead to sudden aggression on its own. Any one of these factors can cause noticeable behavioral shifts.
If you notice heightened aggression in your dog once they enter senior years, it’s best to discuss this occurrence with your veterinarian. Your vet can potentially diagnose any condition that is causing your pet distress, as well as offer ways to bring them comfort in their senior years.
What To Do If Your Dog Suddenly Becomes Aggressive
It is vital to take steps right away to address your dog’s unexpected aggressive behavior. The sudden onset of hostile behavior in your dog should always be taken seriously. Even more important than acknowledging this sudden behavioral change is approaching it correctly, as a negative reaction can worsen the situation. Let’s discuss the recommended steps you should take in addressing your dog’s aggression.
Find The Root Of The Problem
The first step you should take in addressing your dog’s aggression is to try to get to the root of the problem. What is causing your pup to act with hostility? Examining your dog’s life for any potential triggers can help you solve the problem and even prevent future aggression. It is rare for a dog to experience a severe behavioral change without a trigger.
Speak With Your Veterinarian
If your dog is ever experiencing sudden aggression, we always suggest speaking with your veterinarian. The only way to rule out an underlying cause is by seeing a professional and discussing your dog’s history with a vet that knows them. If your dog’s behavioral change is due to an undiagnosed condition, you may never resolve the issue on your own.
Seek Professional Training
Canine aggression should always be taken seriously. Even the sweetest of dogs can accidentally harm us. You’ll need to seek professional training in situations involving aggressive behavior. Professional dog trainers are also skilled in identifying potential triggers in your home. This will help make it easier to get to the root of the behavior.
You could also try an online dog trainer like Doggy Dan for an affordable solution that fits your schedule.
Avoid Potential Triggers
If you can identify a specific trigger for your furry friend, it’s critical to make life easier by avoiding the situation when possible. While not all causes are easily avoidable, some canine triggers are. For example, if it seems like your dog is triggered by new animals entering your home, it may be best to avoid welcoming any new pets.
Final Thoughts
Sudden aggression in dogs has been linked to many potential factors. After reading this article, you’ve likely identified at least one reason why aggression may have become a newly developed problem.
If your pup suddenly becomes aggressive, the first thing to do is to consult your veterinarian. You’ll want to make sure it’s not health-related. From there, you’ll want to work through the steps above with a canine behavioral specialist. It’s critical to address the behavior and work with your dog to correct it, so it doesn’t continue.
My neighbor claims her dog is a service dog which it isn’t. My neighbor has recently become quite ill physically and is stressed out which in turn has the dog stressed. Now the dog is becoming aggressive to other dogs in our building when they are approaching. Personally, I think the dog is protecting the owner due to the owner’s anxiety and ailments. When the dog becomes aggressive, she can’t control the dog and we are in fear the dog will get loose and attack. The dog is DEFINITELY NOT a service dog.
We had two poodles raised together entire life as best friends with never a cross word – One suddenly passed away at age 14 and now the other has developed extreme aggressive behavior including biting both of us – he is on pain meds for arthritis & joint problems but we believe his problem is losing his best friend & we are also extremely sad – Doesn’t this change cause his personality behavior?
My husband has a 4 Yr old collie .never had any problems the last 5 days he has been showing some aggression. But this eve he has stuck his teeth into my finger. And it bled and very painful. 3 weeks he dislocated his ankle and broke 2 bones in his foot so he’s strapped up .I think his new aggression is down to him not have his run in the morning I am very weary of him now and I have little grandkids and I’m concerned about him being nr him any ideas
I have a husky mixed with Queensland female dog and she loves my girlfriend that’s the only person that can grab her and brush her teeth but yesterday night as my girlfriend was going to pet her she suddenly snapped at her we let her cool off and as we called her again she gave my girlfriend a stare and snapped at her again. This morning she didn’t snap at her but she was staring at her and that stare was a scary stare any thoughts on why? FYI her and my girl Have been close since she was a puppy and now all of a sudden she snaps
I found this article very useful. And was able to diagnose why my dog suddenly turned aggressive
It was due to me being taken into hospital and when I came out carers came in who were new to her
Thanks for the advice
We rescued a Pitbull Boxer from dog fighting ring three years ago. They had filed his teeth down. He has bonded with me but can be aggressive towards my husband and daughter. He’s very sweet but can be a Cujo in a blink of an eye. I went away on a trip and while away he bit my husband due to seeing another dog outside. I was gone 7 days. Now he’s being more aggressive towards husband. He lunged at him trying to enter the house and growled at him on an attempted bath. So I tried to bath him and for the first time snapped at me. We have had a behaviorist cone in before. Her email today was avoid triggers! We need more than that.
Hi we are new owners to a Beauceron that is 5+ months old. We went on vacation and my sister watched her for four days for us. She was chewing on things including hands sometimes. She lost a few teeth so far but is still teething. She has been more aggressive with no time in between being good and starting to be bad. Does anyone have any suggestions?
My rescued small 4 year old male beagle mix that has been with me a year and slept in same bed has started to have sleep startle or aggression. If I move or touch him he goes off. Mostly happens at night but sometimes during the day. Why would this start now after I’ve had him a year?
I have a Great Pyrenees he’s a beautiful dog, but all of a sudden he’s been growing or bumping the indoor kennel that we have him in at my girlfriend. He’s about 2 ½ years old and weighs about 110 lbs . He doesn’t do it to me just my girlfriend
We moved house recently to a completely different area and our 8 year old Czech Wolfdog has become extremely territorial becoming aggressive towards anyone or other dog who enters our property. However, she is not stopping at our property but the neighbours across the road. A delivery driver went to their house and she shot over the wall and attacked him, luckily she only scratched him but she is capable of doing some serious harm. She is extremely tense and seems to be guarding the place the whole time. I’m not sure how to tackle this
A local dog behaviorist can likely visit your home and help you assess and treat the situation to hopefully resolve the issue before it goes on too long. We wish you the best.
My daughters two year old Great Pyrenees recently started to get aggressive with other dogs outside the home. She bit a much smaller dog, she weighs 115 pounds. This pup sleeps the majority of the day I would say 18+ hours. Up until the past few months she was a fun loving big girl who loved to play with her brother. No people aggression. Suggestion, should we see a vet first? We have her schedule to go to train and board in a few weeks but wonder if a vet visit is In order. Thanks!
An animal behaviorist expert will be your best bet. While the vet may have some ideas, they are medical experts in most case more so than behavioral.
I have a 18 month female Dachshund she is normally lovely I recently bought her a new toy and she has became very aggressive and protective over this snarling and staring if you get near is the simple answer to take this toy away.
First of all l have 2 female maltipoos. They have never attacked anyone before. Now my daughter moved home and brought her 2 rescue pugells a male and female which are very bonded with each other. Their not aggressive either. Anyways, lately 1 of my maltipoos has started attacking my 37 year old son as he walks in the front door or mostly when leaving. My dog has bit him in the ankle even breaking his skin. I never saw him be mean to my dogs but he has never shown interest in any of our pets throughout his life. Why do you think my dog is doing this now? And what can l do?
I don’t know really where to start, our dog was a rescue from the Bahamas hurricane when we first got her she was definitely afraid of me but trusted my wife and for the first few years she was a great dog she learned to love me as I would show her love but now we’ve had her to the vets we had her to a dog psychologist at $350 which we didn’t find out much she’s been under Two dog trainers and it seems as though nothing helps to give you one example we have two dogs prissy who we are having trouble with and little bit who is a three legged dog we don’t know what to do we’ve had her to the vets numerous of times One last thing this morning I was sleeping as usual on my side and as usual pretty sleeps against my back. When I took my sheet off I thought I startled her and she bit me right above my elbow and tonight I was scratching her and she started growling so I stopped and she came back and I continued scratching but in a different location I just want my loving dog back if you can help in anyway I would be extremely happy thank you and please be safe again thank you very much
My son had a little blood on his hand from one of our dogs who had been playing with our other dog.He was checking the dogs face to see if he was hurt.The dog suddenly growled and snapped at my son.And he has been doing it ever since.Could this be the reason?
Hi,I own a border Coli and he is 1 year old. He has became agresive with people and been biting people three times. I am very sad about it and very worried.
He has never been like that until the last two months. We think is that we took another dog we have out of the house and now he is on his own. Could that be a possible reason to him become agresive?
It is possible – any change in routine or environment can trigger changes. You should consider talking with a local behavioral expert or trainer to see if you can resolve this concern.
I have a 6 yr. old Basett Hound. He has been a very sweet, playful friend. Then a few months ago, he stopped playing and became very aggrsive to me. But mostly at night. I have taken him to his Vet that has been his Dr. since he was 7 weeks old. Because this happens at night she has not seen this happen. I took him for x-rays, nothing. I took him for a CT scan. I do not know what if anything that showed yet. Just did that yesterday. I have been bitten several times. He also went after my Cat for no reason. I am a affraid of my Dog. And I do not know what happened. I am so affraid that I will have to have him put down. I hope you read this, and with God’s help someone has an answer. Thank you, Lorraine
Hi Lorraine,
Perhaps consider talking with a local behaviorist who can come at night or review videos that you make of this behavior, so they can help you out. Wishing you and your dog all the best.
Hi there, I own a rottweiler male at 1.5 years of age. My dad alongside the other males barely spends time with him due to work etc. My mother and I recently started walking our shepherd and our rottweiler and we moved about 2 months ago to a new bigger place. My rottweiler pup has been acting really strange these few weeks. He snapped at my father when my father tried to put his collar on but I’m not sure if it triggered an old memory at the vet (the vet was a male) but even after that he continues to be tense around my father sticking to me only and does not listen to commands my father gives him. He also snapped at my dad when my dad tried petting him on the head. We consulted a friend who is also a dog trainer and she said there is a possible change in the hierarchy caused by my mum and i walking him(the dog). Continuing to seek help my dad talked to one of his friends who was a soldier in the army and his solution was putting a muzzle on the dog and hitting him to show him his “place”. We as a family however do not believe in any sort of physical violence when it comes to animals. My rottweiler then attacked my grandfather who pet him on his head and now refuses to listen to him. Rottweiler pup stares my dad and grandpaps down and slowly circles them he also tracks their movement from the corner of his eye. I dont know if the problem is male related, my neighbour (male) doesnt really like our dogs i dont know if he perhaps done something to our pup.t The most recent incident was when he snapped at my mum . We’ve spoken to the breeder where we got our puppy from and he says the dogs mother exhibits the same behaviour. My rottweiler hasnt attack me or growled at me before he did snap once when i was petting his neck but immediately apologized. I have no idea what to do next we are looking for a new home for him and our last option is to put him down. Please please offer ur opinion because my rottweiler is truly caring when it comes to me but not everyone else.
Please reply
This is an extremely personal decision, but you might consider working with a local behavior therapist or trainer to address your concerns. This is not something that can be resolved via the internet in our opinion – it requires personal attention and customized training for your unique pet and situation. We are so sorry to hear of your troubles and wish you and your dog the best.
Hi, I have a 15 month old Un-neutered chocolate Labrador. He has been trained since day one at 8 weeks to crate with a stuffed animal . I would put my hand in his food bowl to avoid food aggression. His food bowl was in his cage since he came home . he never showed any aggression till he was about a year old . I had given him his food closed the cage as I always did but I needed to get his water bowl and when I opened the cage he gave me a lowered head with a dead on stare followed by a growl. Which caught me off guard and I said no ! And closed the cage because I was unsure how to handle the situation. I am presently taking on line classes for dog training . However I have done so far what I have learned . I removed his food bowl from his cage because I thought maybe it was his space he was guarding . So I placed his bowls in our kitchen where I walk and move around him while he eats to show him I don’t want his food . I have even called him away from his meal time to give him a tasty treat to show him better things come when he’s not guarding his food . I thought we were making progress (but a side note when we are eating he wants to sit beside us and that’s fine but he starts to drool so we ask him to go lay down. ). He is a very loving smart dog that I have trained to do many tricks I play hide and seek with him. Of course I’m the one hiding and he finds me . We take long walks on the state game lands next to us . So he is a very active well balanced dog . He goes most places with me in the car and sits quietly in the car . So I’m confused on his actions . Yesterday we were eating he already ate his just faster then we did . He came into the living room as we were eating and sat next to his dad(husband) and dad made a comment saying look he has not growled today and on the spot he started to growl and took a stance with hackles up( hairs on his back) ears pinned back and dad said no that’s bad . And before I knew it teeth were showing and dad had grabbed him by his color and throat to keep him from biting him all this time it sounded like a fight going on . Husband manage to place him in his crate for our safety and time for him to calm down from whatever reason he has become aggressive. It breaks my heart because I know how living he is . He has never been with anyone but us after we brought him home. He does play with my daughters dog a 11 months old female German Shepard . Now she gets pissy at time and try’s show her dominance over him but he correct her . I was just wondering if you have any ideas as to why he might be acting this way towards us in our home no one else around . . I have done everything so far that I know . Thanks for your time .
Hi, my Nearly 2 year old neutered male has gone into a few fights and it’s really stressing me out so I wound weed if you had any advise.
1st time he got into a fight with a dog he plays with most morning (wasn’t sure how it started)
2nd time he got into a fight with a puppy much younger than him he plays with every afternoon. Not sure how it started. He has been fine since seeing the dog but I’m scared it could happen again.
3rd time he got into a fight with a dog he plays with over a ball. This has never happened before but instead of a growl he went straight into attack.
4th time he was stood on lead and a dog passed and sniffed him and he snapped, luckily I pulled him back before he could make contact.
5th he ran over to a dog near our home aggressively barking but didn’t make contact.
He is usually the friendliest dog and really submissive. There doesn’t seem to be any triggers or pattern. There seems to be no warning just aggressive fight where they need separating.
What used to be my stress relief walking the dog is now the most stressful, worrying if he will go for a dog, do I keep him away or does that create a problem.
Thank you for your time and help.
Thank you very much over the explanation.the reason been that training a Dog is a patient method.but Given you does sign off aggressiveness is a credit to the dogs owner.not being friendly to people.here I rest my case
My chihuahua is 6 years old. Unspayed female. She has toy(sock monkey) that she has had since she was a baby.
I have not ever noticed her going into heat. Except for sniffing the grass and “marking “ the spot. She will also carry the monkey around everywhere she goes.. She has never been aggressive. That behavior ends. Then over some time, it happens again.
My boyfriend and I have raised her together. Now in separate homes.
We have our individual ways, and she is used to this.
He was in the hospital for the last 3 months and is staying with me right now.
She has always laid under the bed covers with him.. Now she has the monkey with her under the covers next to him. But is agitated now towards me.
The one thing that happened in the last week or so is. I ran out of her dog food. I got some from my neighbor. She wouldn’t eat much of it. It was a few days before I could get to the store, because I was sick and he can’t hardly get around.
So once I got to the store, they didn’t have the food she likes.(very picky) but I bought something else.
After that I noticed her looking at me with nasty eyes. It was only another day or so, I got her the right food.
She has turned into Cujo. I don’t know what to do