You are here:

Canine Behavior/New dog aggression


Hello! We have a 1.5 years old Male neutered Australian shepherd named Wyatt. We got him as a pup from a shelter. He is very well behaved in the home, but he showed some over excitement when he approached other dogs so we decided it might be a good idea to get another dog to he can spend time and socialize with another dog. We recently added a 2 year old female spayed Australian shepherd named Kaya. She is a sweetheart to people and other animals according to her previous owner, but she was very aggressive toward Wyatt initially. He seemed to take the hint and gave her the space she needed for a new environment. In fact, she become much less aggressive over time. Wyatt can approach her and even get in her face a little bit and she does not usually react and will accept the behavior. However, Kaya still tends to nip, bite, growl, or lip curl at Wyatt during some strange instances. The most recent being when I play with Wyatt and he is growling. Another happened when she was smelling a toy on the ground and he approached. Or sometimes just when he is around and smelling her. I know that Kaya is not the only one with a behavioral problem, I am sure Wyatt needs to learn how to behave when Kaya tells him to leave her alone, but I am not sure if Kaya knows how to do that without going immediately to a growl or biting phase. I expect her to tell him when he is bothering her, but at the same time I want Wyatt to feel free to play with me, and play growl, without worrying that she will attack. Otherwise their play seems to be fine. Kaya does tend to be aggressive when her and Wyatt are playing one on one. They wrestle and she bites at his ears and neck and jumps on him. She is about 25 pounds lighter than Wyatt though and he is obviously allowing her to pin him. He also keeps coming back for more which makes me think that he enjoys it. Sometimes I worry that I shouldn't let her be so play aggressive with him during play especially since she has a tendency to be seriously aggressive in other situations, but Wyatt really loves playing with her in fact he will whine when they come inside and she lays down instead of continuing play. I know that if I don't have food, toys, attention, or play involved they are both fine, but I want them to be able to communicate without such intense aggression. One because I don't want Kaya to think it's okay to attack Wyatt. And two because I want don't want Wyatt to assume that he should only back off when she attacks and possibly hurting their relationship due to these attacks. Also, absolutely no blood or injury have come from any of these attacks. I took Wyatt to obedience school as a puppy, but Kaya has never been. I know she needs some training, but I just need to know what I should be doing to help them better communicate without it escalating so quickly. Thank you!

Thank you for your question. It actually sounds like Kaya has excellent bite inhibition (the ability to control when and how hard to bite), and that she's communicating excellently with Wyatt. It also sounds like Wyatt is respecting her communication and backing off when she tells him to.

Growling is not aggression. Growling is a totally normal and appropriate communication between dogs. They don't have words. They have growls. And a low growl is the first level of direct communication that says, "Back off, I need space right now." That Wyatt then backs off and gives her space tells me they are communicating with each other beautifully.

If he has failed to back off and so she gives an air snap or gentle contact snap to make her point and he respects that, then they are still communicating beautifully, though Wyatt was a little slow on the uptake.

So when she's resting and he invades her space and she tells him by looking away from him or growling or lip curling or even a snap, she is communicating exactly the way dogs are supposed to communicate. The key is making sure that A)Wyatt heeds the communication and that B)Kaya let's it go as soon as Wyatt backs off.

To do this, when she gives that first signal (the growl - before she feels the need to escalate to the lip cur or the snap), you should redirect Wyatt. Tell him, "She's resting now. Come over here and _______________ instead." You can give him a chew toy or get a tug toy to play with him or invite him for a cuddle or go outside, etc. Or just tell him to lie down and relax for a bit. In my house, when my little one pesters the bigger one, I just tell him "leave him be," and then redirect him to another activity. This way I've got the back of the dog who doesn't want to be bothered. The best way to help Kaya not escalate is to make sure she knows you've got her back and redirect Wyatt when she doesn't want to be bothered.

On the flip side, if she growls and Wyatt walks away and Kaya chases him down to pin him or bite him (and not in a play wrestle sort of way), then you have to redirect Kaya. "OK, Kaya... you made your point. That's enough now," and engage her in another activity. We have to let Wyatt know we've got his back too and won't let Kaya steamroll him.

Regarding their play, it sounds like it's pretty healthy and normal wrestling. Of course, without seeing it, I can't be 100% certain, but biting ears, cheek, neck even legs and pinning is all part of normal wrestling play. The fact that Wyatt allows her to jump on him and pin him, and doesn't appear put out by it, frightened or irritated by it, tells us that he understands it to be in play. The key to healthy play is watching for the body language. I've written a blog about healthy play. It's about dogs at the dog park, but is appropriate for any dogs who are playing together. It provides a brief overview of healthy vs unhealthy play behaviors and when you should intervene. It also talks about time-outs in order to help dogs maintain a happy, healthy interaction. Most dogs will take time-outs on their own during the game, but sometimes we need to help by calling one or both dogs out of the play for a brief distraction.

The easiest rule for play is pay attention to the one you believe to be the underdog in the game. In this case, Wyatt. If he continues to come back for more engagement, if he's not crying, tucking his tail, looking scared, etc., then he is still playing. If it becomes too much or if a bite is too hard, he'll let her know.

As for the times when she growls when he's playing with you or he comes near her while she's got a toy, etc. That's called Resource Guarding. It's a normal behavior among social animals (humans included) and is essentially a fear-based behavior. Basically, there is something that she feels is valuable and she's concerned that Wyatt may steal it from her. That may be your attention/affection, it may be toy or a resting spot or even a super interesting smell on the ground. The best way to address this is through counter conditioning to help her learn that Wyatt's proximity does not threaten her stuff. It will take some time and patience to work on this because you also have to make sure Wyatt feels comfortable and work on these specific issues with Wyatt at a distance from Kaya that she feels comfortable and safe.

Jean Donaldson has a great book called, Mine! A Practical Guide to Resource Guarding in Dogs . It provides a background on the process of resource guarding and how best to address it. The book is dealing with a dog who guards things from humans, but you can adapt the exercises to involve Wyatt. The main thing is that you'll need Kaya to be tethered so she can't access Wyatt if she gets very upset, and you'll need Wyatt on a leash so he can't get closer than Kaya is ready for in that session. This works best when there are two people so one can be with Kaya and rewarding her with tasty tidbits for accepting Wyatt's presence while another person is with Wyatt rewarding him for polite behavior and respecting Kaaya's space.

In the end, the worst thing we can do is punish a dog for growling. It is their first form of communication. It's their best way to tell us they need a little more personal space just now. If we punish the growl (scolding, hitting, isolating by crating or putting outside, etc), we teach the dog that telling us how they feel is dangerous to them. So the dog stops telling us how they feel, but that in no way means they no longer feel that way. The dog who has had the growl punished out of them is the dog who explodes with no warning, causing severe damage because they end up getting pushed far beyond their limits without any ability to say "I need help here!"

I hope this proves helpful. Please feel free to followup if I can be of further assistance.

Los Angeles Behaviorist

Canine Behavior

All Answers

Answers by Expert:

Ask Experts


Jody Epstein, MS, CPDT-KA


IF YOU BELIEVE YOUR DOG IS ILL OR INJURED, PLEASE CONTACT YOUR LOCAL VETERINARIAN IMMEDIATELY. THIS IS NOT THE FORUM TO ADDRESS URGENT MEDICAL ISSUES. I AM NOT A LICENSED VET AND HAVE NO DIAGNOSTIC SKILLS. ***I have been answering questions on All Experts for over 8 years now. I enjoy being able to offer assistance in this forum. I do need to be clear, though. If you’re looking for free advice about a specific behavior question, you MUST submit your question to me via All Experts. If you bypass All Experts and write to me directly through my website, I will ask you to submit via All Experts. On the flip side, if you’re local to Los Angeles and you wish to speak to me privately about an in person consultation, please go through my website. I appreciate your assistance in keeping my volunteer work on the volunteer site.*** I can answer questions about the following canine behavior issues: obedience, timid/fearful & fear-based aggression, nuisance behaviors, families that are expanding with either new human or new animal members and many other issues. If you have potty training questions please first read my trio of blogs at If you still have questions after reading the blogs you can post your specific questions here. PLEASE be as specific as possible when asking a question. Give me a detailed example of the situation - dog's behavior, body language, circumstances surrounding the issue, what the consequences are (another dog's response, your response), etc. I can only provide insight if I can get a picture of the whole scenario. If I ask for further details, please provide them. In person I would normally observe for at least 90 minutes to assess the situation and the dynamics before offering tools and suggestions to modify it. In writing it is ever so much more difficult. Thank you for your participation in the process.


I have been a professional obedience trainer for 9 years, and specializing in behavior modification for 8 years. I have owned dogs my entire life. I own my own dog training and behavior modification business called Nutz About Mutz.

I am a Certified Profession Dog Trainer - Knowledge Assessed (CPDT-KA), #2133301 ; I am a member in good standing with the Association of Professional Dog Trainers (APDT), #77763 ; I am an AKC certified Canine Good Citizen evaluator (CGC), #71253

Publications ; ; Multiple articles in the local pet magazine Pet Press (found across Southern California)

I have a masters degree (MS) in Animals and Public Policy, with a minor in Animal Behavior, from Tufts Cummings School of Veterinary Medicine. I also have 3 years of graduate education in Animal Behavior and Learning from UM-Missoula and UL-Lafayette. I continue to educate myself to canine-specific behavior through extensive reading, online interactive workshops, vidoes and attending canine behavior conferences, workshops and seminars. Beginning in March, 2017, I will be the Behavior & Training Manager at Second Chance Center for Animals in Flagstaff, AZ.

©2017 All rights reserved.