Dog on dog
Plays well with others, understanding and working with
dog on dog aggressive behavior
copyright (c) 2021 Frania Shelley-Grielen. All rights reserved.

What is dog on dog aggression?  We know dog play is not like human play but how
do we know when it crosses the line from play to aggression?  Dog owners want
their dogs to get along well with other dogs but what about the times when we
worry that our dog gets a little bonkers when they see another dog, is not playing
so nicely or that the other dogs are being a little too rough?  Or are they?  Is it
possible that a hard stare, growling, snarling, snapping or more at another dog
in the dog park or on the street is OK?  How do we tell the difference from dog
warnings, threats and impending danger?  What should we be doing to make
sure everyone gets along?  And what do we do when they don’t?  To understand
and work with aggression in dogs towards other dogs we first need to recognize
that what we are often seeing are effective communication strategies for dogs to
increase distance or decrease another’s behavior and not aggression.  For example,
a dog growling at another dog who is eyeing a favorite toy, a dog growling at
another dog who has him pinned to the ground and a dog biting another dog’s
flank and breaking skin, all have different motivations with the first being a
warning, the second of a threat and the third aggression.

Once we learn the content (or what they are “saying”) in dog on dog adversarial
communications, we can determine whether or not we should step in or let the
canines work it out on their own.  To begin, we need to be able to tell the difference
between warnings, threats and aggression.  We tend to overuse “aggression,”
especially when talking about animals, to the point where the word has become a
catchall for every behavior we may think is negative or are not comfortable with.  
This sort of thinking can lead owners to overreact as a result.

The most widely accepted definition of “aggression” is action with intent to cause
harm with “violence” being a form of aggression where the intended harm is
severe or fatal. When it comes to human beings, we can further define aggressive
behavior into “physical aggression” or “verbal aggression.”  For all animals, threats
and warnings are not aggression as they actually serve to prevent action intended
to cause harm from happening if they are communicated effectively, that is “heard”
and responded to.  How we parse out our own warnings, threats and aggressive
behaviors for humans comes from research and from our own direct under-
standing of human behavior as humans.  With animals, who experience the
world in different ways than our own we have no direct experience to draw from
and have to rely more on careful observations of both behavior, context and
studied conclusions of what those behaviors most probably mean.  In a conflict
scenario where dogs are involved, we can more effectively describe behaviors in
these situations as “agonistic behaviors,” which removes the motivation from
either the actor or recipient in a struggle.  Animal behavior experts, Camille Ward
and Barbara Smuts do an excellent job in the following depiction of agonistic
behaviors, possible motivations and contexts as follows:

    “Examples of agonistic behaviors in dogs include threats like muzzle-
    puckering and growling; submissive behaviors like crouching, lowering
    the head and tucking the tail; offensive behaviors like lunging and
    snapping; defensive behaviors like retracting the commissure (lips) while
    showing the teeth; and attacking behaviors like biting. With the exception
    of biting that results in punctures or tears, none of these behaviors
    necessarily indicates intent to do harm. They simply reveal emotion (e.g.,
    anger or fear), communicate intention (e.g., to maintain control of a resource
    or to avoid an interaction) or function as a normal part of play fighting (e.g.,
    growling, snapping or inhibited biting). To determine if an interaction meets
    the criteria for “agonistic behavior,” an observer must focus on an objective
    description of the communicative patterns displayed rather than auto-
    matically jumping to judgments associated with the use of the term

    If signals such as bared teeth and growling are not typically preludes to
    fighting, why do they exist? Paradoxically, such behaviors are usually
    about how to avoid fighting.”

A perhaps more useful way to look at animal behaviors is in the context they occur
in (what is happening and where it is happening) as “distance increasing
behaviors” or “distance reducing behaviors.”  In other words, what is the desired
effect being communicated?  The dog that is squared off, feet firmly planted, lip
raised and snarling is asking for increased distance from whatever it is in the
environment that is threatening, while the dog that initiates a play bow towards
another is asking for reduced distance (and more interaction).  Looking at the
behaviors this way allows for the request, whether of more or less distance by
a change in the environment to be addressed.  So, if the squared off dog is
asking for space from the person or dog approaching than the person or dog
can back off and if the play bow is seen play can begin if the other dog agrees.  
All animals have in common the desire to avoid conflict and the ability to
accomplish that through communication.  Physical fights are biologically
costly for any species.  Injury impacts the ability to gather food, interact
with others and when extreme can be fatal.  To avoid actual fighting animals
have developed highly ritualized bluffs and threat displays, which means they
look the same and follow the same pattern no matter which individual in the
species performs them. That squared off dog, whether Bassett Hound or Basenji
assumes a warning posture with the same rigid body tension,weight forward
on both front legs signaling intent to move forward if they have to.

Dogs communicate with each other through vocalizations such as barking,
growling, snarling, etc., visually through body postures such as play bows, raised
hackles, avoidance, etc. or through scents actively exchanged as in butt sniffing or
odors left behind through urine or feces.  While much of how dogs communicate
with each other is lost on us as humans (who will never be able to hear or smell
as well or fully understand the significance of those abilities to a canine) we can
become more comfortable with understanding how dogs correspond to disagree,
agree to disagree and resolve conflicts.  To do this we have to first work on
observing dogs, all dogs, in different contexts; dogs at play, on walks, behind
fences, tied outside the grocery store, asleep,sitting for attention, and so on and so
on.  Starting with our own dogs, we need to look at what our dogs look like when
they are happy, sad, excited, etc.  What does their face and body look like?  Being
careful not to focus on only one aspect such as lips or eyes or ears but looking at the
whole dog. How does the appearance of the dog change and in response to what?
Learning to read dog body language begins with learning about the natural
behavior of dogs along with paying attention to what is happening around the
dog as much as what the dog is “saying” in response to it.  There are many
excellent sources to learn about dog communication and behavior as long as the
source is a credible one, keep to experts who have formal backgrounds –have
studied the material at a university or graduate level and who are focused on
welfare and science. Videos are particularly useful as they can outline concepts
and show what they look like at the same time, a good example of what play
looks like is this one from
our site and a nice example on canine body language
is this one from
Maddie’s Institute.

Because dogs are a highly domesticated species through convergence in history
with humans their story cannot be told without looking at their wild canine
ancestors. Our modern dog’s ancestors were those canines able to get close enough
to scavenge from, hunt with or become companions to humans.  This key point in
learning about how dogs came to be dogs is to understand that much of dog
behavior is in response to human behavior and how that translates to what we
influence when they are living in our homes, walking by our sides or at the dog
park with us. Not only are dogs living with humans dependent on humans for
pretty much everything they get to do including who they get to socialize with
dog or people wise, whether or not they have been taught how to act appropriately
around dogs or people, if that training created good positive association or was
painful, and whether or not they get to work out conflicts and potential conflicts
on their own.  As veterinary behaviorist, Petra A. Mertens writes:

    “Free ranging dogs can avoid conflict more successfully through avoidance of
    encounters with other dogs, making fights less common.  Space restrictions
    and the influence of caregivers’ attempts to control the behavior of the dogs
    may catalyze problems and prevent resolution using ritualized behavioral

Our discussion of dog behavior with other dogs here is really about dogs behaving
with other dogs around people, in fact, most studies in working with dog on dog
“aggression” are primarily focused on humans redirecting the dog while the dog is
attached to the human with a leash or an aversive device such as a head halter.  
These studies are really reflective of how well the human teaches the dog what to
do in their presence. Interestingly enough, the same studies often find that without
the human present or ongoing training, the dog reverts back to whatever the
behavior was in the first place. Studies on dog freely interacting with other dogs’
show that while dogs may “argue” with a full suite of distance increasing behaviors,
threat displays or warning signs, dogs mostly do not attack each other:

  • A 2011 study done at a dog park catalogued 127 agonistic interactions with
    none resulting in injury.

  • In a paper on dominance and aggression in multi-dog homes, Petra Mertens
    noted that: “fights between co-habitating dogs represent between 5% and 18%
    of the overall caseload of veterinary behaviorists.”  Most of the fights being
    about proximity to food or toys 48%, proximity to caretaker 43% defense of a
    preferred resting space 23%.  (Mertens says if this is about resources letting
    the dog with the most resource guarding potential have access to same when
    calm is most effective in defusing future fights.  This is in effect giving them
    what they are the most worried about not having which lessens stress which
    creates a calmer dog.)

  • A 2016 study looking at multiple dogs and their interactions with other dogs
    in a doggy day care and in the home found that about half of the dog pairs
    observed at a doggy day care never interacted aside from mutual sniffing.  
    New dogs were introduced into the environment on an ongoing basis and the
    study concluded: “In these circumstances, establishing a relationship with
    every dog and negotiating dominance would require a lot of time, energy and
    social cognition.  The ability to completely ignore a social partner who is in
    close quarters is probably another alternative strategy that dogs use to avoid
    conflict, and may have become more adaptive as the social environments of
    dogs changed from that of their wolf ancestors”.

It is important to point out that those studies done in dog parks, doggy day cares
and in homes with multiple dogs are most probably looking at dogs that are fairly
well socialized and already play well with others. These sites are often a filter and
rambunctious dogs are often not present at all.  Owners, knowing their pets, will
often only bring dogs that behave appropriately already to these environments,
rules are often posted or enforced restricting the presence of dogs that are prone to
not interact well and often preventing the presence of intact males or females in

So having said all this, how and when do we know when too much is too much with
dog on dog behavior?  As much as this may be equal parts informed intuition, a
good grasp of dog body language and experience it can still be a tricky
determination. Here are a few tips to help:

Never forget who the responsible party is on the other end of the leash-
.  Think through possible scenarios and solutions ahead of time by reading
and researching.  Remaining calm to provide affiliation and social support for
your dog is the most important thing to remember and know how to do.  
Whether it is taking a deep breath, reciting a soothing affirmation or whatever
you need to do to keep your presence neutral is vital.  A tense handler makes for
a tense dog. Our dogs are experts at reading our body language and sensing stress
induced chemical changes (we smell different when we are nervous).  It is highly
likely that your dog senses your stress before you even realize you are experiencing

Survey the situation first, let them know what you think, ask, decide and
then act.
Look ahead on your walk for approaching dogs or situations that you
know rile the dogs. Do not wait until you are interacting with it, set you and your
dog up for success.  Cue your dog in advance with asking for the kind of behavior
you want and reinforce - "Doodle, easy.  Good Easy Doodle! Good Easy!, Good Easy!,
(etc.)"  Keep the dog engaged and keep reinforcing until you are past.

We know that a loose, wiggly body on another dog is a good thing and even better
if the dog is of the opposite sex than the one we are with for interaction.  Look at
who is coming toward you on a walk, looks good?  Ask the other handler if the dog
is friendly/wants to say hi and what sex- cross gender is always the safest bet,
then let them do it.  There is nothing more frustrating to a dog than being held
just close enough to sniff another but not close enough.  If your dog is straining
at the leash with two feet off the ground you are creating and feeding frustration.

It is good to know that you can walk in another direction, cross the street, and stand
between two parked cars to avoid a situation.  It is even better to learn how to
calmly deal with one.   Know that your body can always be used as a buffer
against the environment and provide a safe zone by putting you between the
hazard, dog or person.  Shorten the leash so your dog is closer to your side by
running the hand that is not holding the leash down the leash and against your
body, this will put your dog closer to you without pulling on the dog.  Once you
put yourself between the oncoming dog and your dog, both dogs will breathe a
sigh of relief.

Lean the art of the neutral introduction:  Having company over and that includes
their dog?  Meet your guests with your dog on the corner and walk together to your
home.  Dogs do not equate territory with just your house or apartment, the  street
and sidewalk are part of what “belongs.”  Meeting on neutral ground and going to
your home together removes the “intruder” tension.  Bringing treats with you to
reinforce the neutral behavior for all dogs never hurts –make sure to have each
owner treat their own dog.  Allow for butt sniffing, particularly as walking, this
sort of linear introduction is highly effective for familiarizing dogs without pressure.

Master entrances and exits that disperse energy: When entering the dog
park with a dog make sure the dog is unleashed between the double fences before
entering to guarantee an even playing field where all dogs can move around freely.  
Move directly to the middle of the space as soon as you enter, your dog and the dogs
in the park will follow.  Most squabbles in dog parks occur at the fenced entrances
where entering dogs attract the attention of the dogs in the park.  Multiple dogs
lining up at a fence creates a confined space where excited bids for attention and
exploration are easily intensified.  Walking immediately to the center of the park
allows for a full use of the space to both explore and retreat.  Keep talking to a
minimum to allow the dogs to interact with each other and not focus on you.  
Make sure to keep your hands at your sides, raised hands invites jumping and
avoid direct eye contact with any dog. For exits and entrances from your home,
be first so that you can see what is coming up ahead and cue your dog accordingly.

Remember separate by size and play style:  wisdom for most, if not all, dog
pairings.  Dog parks often have two play areas, one for small dogs and one for
large dogs, in a scenario with a small dog that plays too intensely for his same
size companions, try the big dog park on for size.

Become comfortable with asking your dog to return to you (“recall”).  Get
your dog comfortable with this by training them to answer to your recall request,
offering them a treat as a reward and immediately releasing them back to play so
they learn a recall is never a punishment and you get to use the request when you
need it.  To train this, call the dog using their name and a request like “Come.”  This
would sound like “Daisy! Come!”  Use a happy and excited tone and try clapping
your hands and backing away from your dog while facing them to get them to
follow.  Do use a treat and make sure when the dog reaches you to reward them
with the treat and a “Good Come!” so they know they have done what you want.
Immediately release the dog with a “Go Play!” or “OK!” and ask for the recall again.  
(Never, ever use this request to place a dog in a place of confinement such as a crate
or a closed off room.)

Practice the recalls and releases at home and in the dog park.  This is ideal to do
without other dogs initially and with a partner you can take turns sending, calling
and releasing the dogs. Once you have a few sessions of your practice recalls and
releases down, try them out in the dog park with other dogs around.  Do not exceed
three recalls and releases initially.  And always, always reinforce with treats, praise
and releases.  Once you have this down, even if everyone is playing well, make sure
and practice it at least once or twice during your park visits so it stays relevant.

Learn to offer a correction or redirection with a calm neutral tone, fluid
timing and reward the response.
In a scenario where you do not like what is
happening in the dog park use your recall and redirect the energy with throwing a
ball or a stick.  Have an overly boisterous mounter ("humper") and the other dog
looks ready to lunge in response?  Refocus the energy on interacting towards
something else beside the other dog.  We can never just call a dog away from
something and expect them to forget what it is that has gotten them so excited;
we have to provide a distraction that just is as exciting.  An in the moment “uh
uh” followed by a “Good Dog!” when your dog responds followed by calling the
mounter’s name  and then tossing a ball for redirection is a skill worth it’s weight
in gold.

After some time at some thing else, let them go back to each other.  Remember the
rule of thumb with separating dogs at play; if you separate two dogs and the
“victim” dog follows the “bully” dog for more play afterwards, you have just
broken up a perfectly good play session.  Learn from it.

In the dog park continue to reinforce the behavior you want.  If the energy starts to
shift allow for time for the dogs to sort it out on their own, this is best followed with
two dogs,with two dogs overly threatening one other dog, interrupting sooner
rather than later is safer.

Get over "humping."  First, the correct terminology is "mounting" mostly because
this behavior which may look sexual is not (actual reproductive mounting has a
different pattern of behavior).  Mounting is an attention getting behavior that a
frustrated or bored dog engages in.  Dogs tend to play in pairs and mounting is
usually seen when a third dog wants to join in and is ignored.  Work on redirecting
the energy of the mounter by engaging them in something else such as running
after a ball, a tug of war, etc. (See
more ).

Know when to break up an interaction:  Use your words first employing a calm
and neutral tone.  Make sure you are close to the dogs you are addressing and not
shouting or calling over a distance.  Never yell at the dogs as this will increase
arousal not lessen it.  Call each dog by name and follow by a specific redirection.   
Never put your hands in between two dogs but do employ body blocking if you
need to get in the middle of dogs and know that your legs are the strongest part of
your body.  Should you see a dog biting or breaking the skin of another dog or
threatening behavior that is not provoked such as pinning or standing over
another dog while vocalizing or if a dog displays serious warnings or threats
towards a human such as snarling with bared lips, growling, aggressive bark,
snapping or biting- the dog should be removed from the situation immediately.
(For more on breaking up a dog fight see

Know that most of what we do not intervene in will be resolved without us.  
It’s a complicated determination that gets easier the more we know.  Remember, as
owners we never want to train out a warning, the old saying of not training out a
growl is an important one to remember.  We want our dogs to be able to offer that
warning growl instead of learning that they cannot exhibit this and having to go
right for the bite instead.  Trainer, Aimee Sadler in advocating group play for
shelter dogs, offers excellent advice on the danger of “punishing the thought” as
opposed to the actual behavior:

    “Don’t focus on the minutia of body language.   None of these signals tells us
    very much on their own.  Try to take in the whole picture in order to best read
    the dogs in front of you.  Allow dogs to communicate with one another.  What
    is the other dog doing in response to those communication signals?  Do not act
    right away if you spot signs of tension and stress.  Do not “punish the thought”,
    by correcting these communication signals.  Always wait until there is an
    actual behavior that needs correcting.

    Remember the goal of play groups is for dogs to learn how to communicate
    with one another appropriately, which may sometimes include brief
    arguments, in order to establish themselves with one another.  We do not
    dictate dogs’ relationships with one another (the dogs decide who they like
    or do not like), but we do monitor their behavior, stepping in only when

The more you know about dog behavior and the more your dog can experience
positive interactions and get through minor quarrels with other dogs is the best way
for your dog to learn how to play well with others and for you to enjoy it too.

This article is an original work and is subject to copyright. You may create a link to
this article on another website or in a document back to this web page. You may not
copy this article in whole or in part onto another web page or document without
permission of the author. Email inquiries to

Ward, C. and B. Smuts (2011, April-May). Dogs Use Non-Aggressive Fighting to Resolve Conflicts.
Bark, 65-68. Retrieved from

Echterling-Savage, K., DiGennaro Reed, F.D., Miller, L.K. and S. Savage. (2015). Effects of
Caregiver -Implemented Aggression Reduction Procedure on Problem Behavior of Dogs.
Journal of Applied Animal Welfare Science,
18-2, 1-17.

Orihel, J. S. and D. Fraser. (2008). A note on the effectiveness of behavioural rehabilitation for
reducing inter-dog aggression in shelter dogs.
Applied Animal Behaviour Science, 112-3, 400-405.

Capra, A., Barnard, S. and P. Valsecchi (2011) Flight, foe, fight! aggressive interactions between
Journal of Veterinary Behavior: Clinical Applications and Research, 6-1, 62.

Mertens, P. (2004) The Concept of Dominance and the Treatment of Aggression in Multidog
Homes: A Comment on van Kerkhove's Commentary.  
Journal Of Applied Animal Welfare Science,
7-4, 287-291.

Trisko, R.K., Sandel, A.A. and B. Smuts (2016) Affiliation, dominance and friendship among
companion dogs.
Behaviour, 153-6-7, 693-725

Sadler, A. (2014) Dogs Playing for Life. Retrived from
(fPat Murrary) Both the boxer and the daschund
are telling each other they want to play.
"We tend to overuse “aggression,”
especially when talking about
animals, to the point where the
word has become a catchall for
every behavior we may think is
negative or are not comfortable
with.  This sort of thinking can
lead owners to overreact as a
(Stewart Black) Dogs are oral and use their
mouths for all kinds of things including
play.  The Dalmatian's play bow is easy for
us to see.
(fPat Murray) The boxer may look "worried"
to us but allowing these dogs to interact
with our neutral reaction is the best approach.

Request an individual consultation
(Eric Sonstroem) Loose and relaxed faces
and interactions are easy to read but
dogs do more in play too.
(Jim Kelly) Having one dog restrained and
the other loose is never a good idea.
Notice the tension and ear position of
the tethered dog.
(Crystal Rolfe) Make sure to remove all devices
of restraint so dogs can play along,
especially with head halters which inhibit
behavior and can compromise breathing.
"Most squabbles in dog parks
occur at the fenced entrances
where entering dogs attract
the attention of the dogs in the
park.  Multiple dogs lining up at
a fence creates a confined space
where excited bids for attention
and exploration are easily
intensified.  Walking immediately
to the center of the park allows
for a full use of the space"
((c)Frania Shelley-Grielen) Dogs play in pairs
even when other dogs want in on the fun.
copyright Frania Shelley-Grielen
copyright Frania Shelley-Grielen
"Having company over and that
includes their dog?  Meet your
guests with your dog on the
corner and walk together to
your home.  Dogs do not equate
territory with just your house
or apartment, the street and
sidewalk are part of what
“belongs.”  Meeting on neutral
ground and going to your home
together removes the “intruder”
tension.  Bringing treats with
you to reinforce the neutral
behavior for all dogs never
hurts –make sure to have each
owner treat their own dog."
copyright Frania Shelley-Grielen
212-722-2509 / 646-228-7813

Website copyright Frania Shelley-Grielen is a participant in the Amazon
Services LLC Associates Program, an affiliate
advertising program designed to provide a means\
for sites to earn advertising  fees by advertising and
linking to

Best viewed in
Google Chrome