Dog on dog
Plays well with others, understanding and working with dog on
dog aggressive behavior
, copyright 2017-2018 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 understanding 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 automatically jumping to judgments associated with the
    use of the term “aggression.”

    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

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 patterns.”

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 heat.

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- you.  
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 it.

Survey the situation first, let them know what you think, ask, decide and then
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

Remember separate by size and play style:  wisdom for most, if not all dog parings.  
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 perfect to do
without other dogs initially and with a partner so you can take turns calling the dogs
and releasing them. 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 3 recalls and
releases initially.  Once you have this down, even if everyone is playing well, make sure
and practice it at least once or twice during a park visit 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 you’ve been
listened to followed by calling the mounter’s name 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

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


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 necessary.”

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 well with others and for you to enjoy it too.

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! aggresive interactions between dogs.  
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 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."  
(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 to both explore and retreat."
((c)Frania Shelley-Grielen) Dogs play in pairs ("dyads")
even when other dogs want to be a part of it.
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.  
Allow for butt sniffing, particularly
as walking, this sort of linear
introduction is highly effective".
copyright Frania Shelley-Grielen
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