Sudden Aggressive Behavior with Biting

[REBECCA CONGDON]

We have 2 full-bred female German shepherds. 10 month old. We also have a 10 year old rescue GSD & 2 other mutts. We bought the 2 girls in hopes to breed them with a stud, therefore they are not spayed. In the last 5 days, we have witnesses unprovoked aggression with biting. In one event, our neighbor walked into our yard & they both barked, charged & bit on hip. Of course, it wasn’t serious because we were right there. Then, we had an incident with UPS driver who typically plays with them, gives them treats in the past. This past weekend, they charged him & bit. We see no other signs of aggression within the home. We have a large farm so the pups have lots of exercise. They are contained within a 2-3 acre area of our yard with invisible fence. In the meantime, we have made signs for deliveries to go away from their free area & are not leaving them outside unattended. I ordered the program in hopes to help them myself. $3000 a dog for aggression training is not feasible for us. Any help within this forum is greatly appreciated. All of our prior docs have been adults from humane society. Thanks!

[Adrienne Farricelli]

Hi there,

Welcome to the forums,

I am so sorry to hear about these last bite incidents, this must be very upsetting! I have a few questions:

How long have you had these 2 female GSD? 

Where did you get them from?

Are they littermates?

How long ago was the invisible fence set up?

Were they always perfectly fine with people entering your property/home before these incidents?

Do they "team up" and bark at people walking by the fence?

Did the bites break skin?

Did the first neighbor and UPS driver come into the yard on their own or did you let them in? Were you present in both cases?

Did you notice whether one dog in particular is doing the biting, while the other watches?

Were both bites when the people were leaving (showing their backs)?

Did you see any precursor aggressive behavior prior to the bites? Barking, lunging, growling, baring teeth?

Are they kept out in the yard on their own most of the day?

Thanks

[REBECCA CONGDON]

Hi Adrienne! We purchased these 2 pups in October. They were born in July 2021. I believe they were 13 weeks old. They are littermates. We purchased them from an AKC breeder. Legit one, not a puppy mill. We plan to breed them with a stud, eventually. The invisible fence has been in for years, but we trained them in January of this year. We have no issues with them in that regard. Yes, they have always been perfectly fine with people entering the yard. They bark at the neighbors dogs, but people can walk by & they have never paid much attention to them. The first incident with the neighbor, I had yelled across the street before he walked over & I had believed that I startled them by speaking loudly. They immediately began barking & running toward him. He has known the pups since they came here, so he wasn’t scared but they wouldn’t quit barking. He began to turn away & one bit him. I’m not 100% sure which it was, unfortunately. We were concerned about him & my husband grabbed them to keep them from doing more harm. The second incident was a week later & unfortunately we didn’t not witness. They were in the yard & the normal delivery man brought the package to the steps & then they bit him (as he walking away). Both bites broke skin. They have never shown any aggressive tendencies at all. We have 5 children & have never even growled at them. Most day, they are kept in the yard within the invisible fence. Especially, if we are working. We have 3 other dogs & they all room & play and then chill on the porches on the chairs & couches. Upon research, I am learning that they should not be left unattended at a young age, so we will begin to crate them again during work hours. We have changed our delivery to a garage that is outside the perimeter of the incisible fence, but we are still worried about visitors. I have made an appt with a local training facility for weekly trainings, but they cannot begin until June. I was hoping your online sessions will help me lay the foundation. They are very chill dogs. Like to cuddle, not anxious & listen well. 

[Adrienne Farricelli]

Thank you for the extra details, they are very helpful! I will try to cover several of your concerns and then go deeper into how these issues can be tackled, but since there is a bite history, for safety and correct implementation of behavior modification, I recommend working along with a reputable dog behavior professional specializing in dog aggression using force-free behavior modification techniques. So let's get into some nitty-gritty details. 

So to recap you have described to me owning 2 purebred intact female littermate German shepherds since October that are now 10 month old (and which you plan on breeding) sharing the household with a 10 year old rescue GSD and 2 other mutts obtained from the human society as adults (thank you for rescuing!). You have described issues with the 2 GSD dogs who in the last 5 days have exhibited unprovoked aggression involving biting. One incident involved your neighbor who walked into your yard and ended getting bit on the hip. The second incident involved a UPS driver with a history of playing with them and giving them treats who also ended up getting bit. Your dogs though appear to act normally at home (with your 5 children) and have been perfectly fine with visitors entering the yard until now. Your dogs receive lots of exercise and are contained in 2-3 acres with an invisible fence most of the day, especially when you are working. 

OK so there are several aggravating factors we need to consider:

1) Being littermates. 

While littermate syndrome in dogs hasn't been researched enough, we have lots of anecdotal evidence about it. What is reported often is competitive behaviors among the two dogs, and the more similar the dogs are, the more competition develops. With littermates being the most similar two dogs can ever possibly be, we can therefore deduce why they often end up getting into conflict with each other.  You may not see competitive behaviors among them yet, but they may possibly pop up later on as they develop and sometimes can lead to some nasty fights.

On top of this, as littermates grow together, they become strongly bonded and that often puts a dent in their receptivity to us (ability to attend to us and following our guidance and directions).

Left together outside, they may likely form a sort of teamwork modality and co-dependency. It could likely be that one dog in particular is the biter, but the other dog joins in just to work as a team. This can be said with any dogs living together, but in littermates such issues are more established. 

German shepherds are also prone to same-sex aggression which may raise its ugly head at any time, and things can get particularly heated when they reach the estrus stage. Due to this reason, many reputable dog breeders won't send littermates to new homes, although there may be some rare exceptions. 

2) Territorial predispositions

You already mentioned taking measures to prevent them outdoor access and that is great as well as not allowing visitors to show up announced. As you may know, German shepherds are described as being vigilant dogs who remain poised, but when the circumstance demands, switch into being eager and alert, with a willingness to put their life on the line in defense of loved ones. 

 

These traits have made German shepherds cherished guardians of the home and farm. These dogs are not the average Golden retriever who, as "social butterflies" rush to great and befriend anyone they meet. Rather, as German shepherds mature, they edge more on the reserved side and their standard clearly states that their aloofness "does not lend itself to immediate and indiscriminate friendships."

 

With this breed's innate predisposition, it is therefore important recognizing how, without proper socialization, training and guidance, one is walking on a fine line. With not much guidance (such as being outdoors on their own) a German Shepherd's natural aloofness can therefore easily morph over to suspiciousness, mistrust, and even excessive territorial aggression.

 

3) Age of onset 

In general, young German shepherd pups are happy and eager to greet people. As they meet and greet, they are all wiggly and may solicit attention and petting from people. Things may start to change though when German shepherds reach the adolescent stage, a time when their attitudes about people being nearby their properties shifts into territorial behaviors.

 

At around 8 months, you may start to notice how strangers or other dogs approaching have now become potential threats. From wiggly, a young teenager GSD may now bark or even growl upon noticing intruders. Of course, not all dogs follow this timeframe, and may take longer to develop this. 

 

While it's rather normal for German shepherd pups to act this way, you want your puppies to engage in these protective instincts later on, as they develop so that they're  mature enough to make better decisions.

When we are not around, the ideal guardian dog will carefully evaluate the situation and may emit a low-level threat, under the form of a bark or a growl, then, based on how the intruder reacts, they may react accordingly. Problems arise when German shepherds take the role too seriously and engage in territorial aggression ignoring the owner's requests to settle or when the aggressive display is directed towards people who have shown no signs of threat or aggression.

Whether a German shepherd develops territorial aggressive behaviors or not may vary based on several factors such as hereditability (the puppy’s parents were prone to being fearful/aggressive), lack of socialization and training, encouragement for the behavior and lack of guidance (puppy left alone to make bad choices). 

When a predisposition for territorial aggression is combined with the immature adolescent stage and lack of confidence, this can become a recipe for disaster. As an adolescent, pups often struggle making savvy decisions about who is friend and who is foe. This should not be underestimated, as even a young adolescent German shepherd can cause harm with sharp teeth. 

So this could have been part of that "teenage flakiness" stage where their immaturity has led them into trouble and a misjudged non-threatening situation, so we need to take steps for not allowing this to happen again. 

You can read more about the teenager stage here: https://www.braintraining4dogs.com/members/archive/survive-dogs-adolescent-stage/

4) Presence of invisible fence

I know that you mentioned that you have had no issues with it, but there are some potential issues of them triggering territorial aggression. Let's take a closer look into what may be happening. According to Dr. Dodman: “there’s enough information to suggest that an invisible fence may increase territorial aggression. It can make territoriality even more pronounced near the line."

The issue is that an invisible fence allows people like the the mailman, the pizza guy and the child whose ball landed right by the edge of the property to trespass the dog's perceived property. That inability to keep these people out makes dogs feel more on edge and reactive and can lead to even biting. 

5) Breaking skin

When we evaluate prognosis for dogs who bite, we refer to a bite scale. The Ian Dunbar bite scale goes from 1 to 6 with 1 being no skin contact and 6 causing death. Your dog/dogs managed to break skin so it's not level 1, but may be level 2 or 3 or possibly even 4 depending on how deep it was. A level 2 is known to be the be one of the best predictors of a good outcome being that it is sign of a certain level of bite inhibition, although we can't make generalizations.

6) Home with kids

I am always concerned about dogs who bite when in a home with kids. Sure, they can be wonderful family dogs, but a bite history tells us that they are likely to bite when the right circumstances present and that their bites can break skin and cause considerable damage to young child's skin. While they may do fine with your kids, we need to think about what could happen if your kids bring friends into the home and for some reason something triggers a need to bite. We can manage the situation, but there are always risks with kids that a door is left unlocked or a gate unlatched. 

7) The unpredictability

You mentioned that the bites were "unprovoked" and this also raises a concern. We like when we can identify easily triggers because that gives us predictability and with that comes a certain level of control. If you mentioned that they reacted  when the neighbor yelled at you in a threatening manner or raised his hands up in the air or when the UPS guy was wearing a big hat and sunglasses, we know that we can work on those triggers which gives us a better prognosis. When things occur unpredictability, we lack information on what exactly to work. 

Sure, there are good chances there might have been a trigger that we haven't noticed. Maybe, your yelling truly alerted them, making them think you were under attack and you were "barking' at the neighbor aggressively, and from that day on, they decided that nobody entering the premises is welcome, but we can't be 100 percent sure on that. 

So these are some things that concern me. On the plus side though, they are still young and it can happen that their immaturity has led them to misjudge things. Another plus factor is that this behavior is fairly new and new behaviors are easier to be nipped in the bud compared to older ones with a long history of rehearsal. 

So here are some general thoughts, but please note that I am not there to observe the behavior and cannot make an accurate assessment. Your dogs may need a less or more involved plan depending on various variables and factors. Also, we need to consider whether this incident could have been triggered by some potential medical issues lowering the dog's bite threshold or whether they may be going into heat causing them to become more reactive. 

-Safety: Safety of people is of the upmost importance, hence the importance of having strict management rules in place. 

Following are important management measures, always best being safe than sorry. :

• Dogs are no longer allowed to be outdoors in the yard unsupervised (which you are already doing)
• Nobody should ever enter the premises unannounced 
• Secure all gates and doors to prevent mishaps
• Place window film on windows to prevent habit of barking at cars or passerby
• Keep the dogs locked in another room or behind a secure pet fence or baby gate when guests are over and preferably separated from each other
• Disable the doorbell and put a sign to avoid visitors to knock. They should call you instead giving you the exact time of arrival so you can lock your dogs. 
• When outdoors, take turns having each dog tethered to you on a long leash.
• Keep the dogs separated when around triggers
• Purchase a dog on premises sign. Consider that beware of dog sign could open up the possibility of property owner liability if the dog escapes.
• Keep dogs always leashed on neighborhood walks since many dogs perceive their neighborhoods still as their territories and walk each dog separately. 
• Keep dogs away from children visiting. 

-Importance of Management 
Because rehearsing territorial aggressive behaviors makes them more established, it is vitally important to implement management. Management simply means taking steps to prevent the dogs from practicing the undesirable behavior. 

Here's the thing, even allowing a certain degree of territorial aggression could potentially undermine the best behavior modification plan, because it allows the dog to act on her own judgement potentially contributing to making bad choices in the future. 

On top of this, consider that allowing dogs to engage in undesirable behaviors that are self-reinforcing sometimes yes and sometimes no, put them on a variable schedule and makes dogs more eager to engage in them sort of like the addicting nature of gambling and winning every now and then in Vegas. 

In cases of dogs who act aggressive or have managed to bite, their license to protect may therefore need to be revoked so to play it safe and avoid rehearsal of problematic behaviors. 

Management doesn't solve the issues directly, but prevents them from getting worse. Behavior modification is what tackles the root causes. 

-Body Language 101

All owners of dogs who have demonstrated aggression benefit from learning all the signs dogs give before they start feeling uncomfortable and likely to react.  Recognizing early precursors signs of the dog being uncomfortable in a situation is important so to prevent the dog from going over threshold. Here is a read about threshold levels in dogs:

https://www.braintraining4dogs.com/members/archive/threshold-levels/

Signs of stress/fear

https://www.braintraining4dogs.com/members/archive/signs-fear-stress-dogs/

-Use of Desensitization

If the biting stems from territorial aggression, German shepherd dogs need to be exposed to low levels of the stimulation known to trigger the behavior. This is accomplished by using desensitization, a step-by-step systematic approach where dogs are exposed to low levels of stimulation so that they are kept under threshold. 

More about desensitization is covered here: https://www.braintraining4dogs.com/members/archive/desensitization/

Often one starting place is distance. Dogs are better under control and capable of being more responsive and receptive to training if we present intruders from a far distance. 

-Use of Counterconditioning

Desensitization works best when coupled with counterconditioning. In counterconditioning the goal is creative positive associations with triggers (cars, people approaching the dog's territory) so to change the dog's emotional response to them. 

From wanting intruders to go away, dogs may therefore start looking forward to seeing them because they have associated them with great things (like tasty treats).

More about counterconditioning: https://www.braintraining4dogs.com/members/archive/counterconditioning/

The goal is obtaining what is known as a "conditioned emotional response" where the dog looks forward to the trigger appearing rather than dreading it. More about this here: https://www.braintraining4dogs.com/members/archive/conditioned-emotional-response-cer/

Desensitization and counterconditioning works best in the cases where territorial aggression stems from underlying fear, which in many cases does. 

-Implementing The Training 

Once the dog's emotional response has changed, and the dog is in a learning state and less over threshold, it is possible to implement some training. Hopefully, your German shepherds have been trained to respond to several cues.

If not, you will need to very deeply train each of your German shepherds separately starting in low distraction areas. It's important training them separately so they don't feed off each others emotions in face of triggers. Then once reliable, you can train them together, but always starting under controlled settings (like dogs together, but one handler with one dog with the leash on) and making safety always top priority. 

German shepherds are working dogs and they thrive on being kept busy with training and brain games. A well-trained German shepherd dog should demonstrate the ability to be under good voice control in spite of seeing triggers. Once this level of fluency is obtained, each German shepherd can be kept on leash when guests or delivery people approach and be responsive to the owner's requests. 

The dog therefore can be trained to look at the owner and rush towards him/her rather than charging at people or lie down at a mat rather than barking at visitors. 

Other helpful exercises:

https://www.braintraining4dogs.com/the-airplane-game/the-smacking-sound/

https://www.braintraining4dogs.com/members/brain-training/university/look-at-that/

https://www.braintraining4dogs.com/members/video-archive/train-dog-go-to-mat/

https://www.braintraining4dogs.com/members/brain-training/obedience-101/recall/

https://www.braintraining4dogs.com/members/brain-training/obedience-101/take-leave-it/

-Prognostic Factors

Depending on each case, there may be different outcomes. Following are several prognostic factors.

-How long the behavior has been practiced. In general, the longer the dog has been allowed to rehearse the problematic behavior, the longer it will take to work on it. 

-Genetics. German shepherds coming from protection lines or from breeders who have paid little attention to temperament may be more difficult to treat. 

-Age. In general, dogs over the age of 1 may be difficult to treat since they may no longer be as malleable as younger dogs. 

-Owner commitment. The more committed and willing the owners to manage, supervise and train, the more they may be more likely to succeed. Having the whole family on board on management can help. 

-Level of management. Families able to better manage their dogs' environment are more likely to succeed. 

-Level of dog bites. The more severe the dog bites, the more risks involved, especially if there are children living on premises who enter/exit the home with friends. 

Last but not least,  I would also carefully evaluate whether your pups are worthy of breeding. 

I always hate to sound judgmental, but I think it's important in this case to carefully evaluate things. I know they must be wonderful and stunning dogs, but we need to carefully assess the situation and see how things fold out as they mature. I would highly suggest having a trainer/behavior professional carry out a temperament test so to screen out for fearful behavior, and possibly, individualizing which of the two dogs did the biting. The modus operandi of the bites appears to be biting when people were about to leave/turning their backs. This is the classical approach of fearful dogs. Fearfulness is a big problem in this breed and can be passed down from a generation and another. Sterilization may therefore need to be considered if that's the case and also to prevent moodiness during the estrus cycles (unless steps are taken to manage them) . 

I hope this helps!

Let me know if you have any questions!

Disclaimer: behavior modification comes with risks. Articles, videos and general info found in the forums or course (or any online source) are not meant to replace in-person training/instruction. By using this course and forum, you are waiving any liability claims or other type of claims related to any dogs' behavior against you or others.