Dog on dog
Plays well with others, understanding and working with dog
on dog aggressive behavior
, copyright 2017-2019 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 impend-
ing 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 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 threaten-
ing, 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 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 research-
ing.  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 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 3
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 excell-
ent 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.

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
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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 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
(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 or "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, partic-
ularly as walking, this sort of
linear introduction is highly
copyright Frania Shelley-Grielen
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