Aggression in Dogs & Cats

About the Diagnosis
Aggression is a natural behavior of dogs and cats. Pets that are in pain, stressed, and
under duress will often show signs of aggression. However, aggression in the home and
uncontrolled aggression should not be tolerated in pets. These pets are potentially
dangerous to themselves and others. Furthermore, owners of aggressive pets are
ethically and legally liable for their pets’ aggression.
It is important to note that aggression is generally felt to be a learned behavior in dogs
and cats. These pets have been trained (usually unintentionally) to be aggressive.
Because of this source of the problem, medical/drug therapy by itself is rarely if ever
There are several recognized classes of aggression found in dogs:
Status or dominance aggression can be a problem within the household or when
interacting with new individuals. It can be interdog aggression, aggression toward new
people, aggression toward strangers, and so forth. Similarly, protection of property (the
house, the toy, the owner, etc.) can lead to aggression.
Fear aggression can sometimes be difficult to predict. Dogs reacting out of fear often do
not provide warning behaviors. No bark occurs before the bite. Dogs can sometimes
have fear aggression when woken from sleep, but be perfectly loving dogs at any other
Prey or food aggression is a natural instinct that may be only slightly displaced. This can
cause dogs to bite cherished members of their pack (e.g., people and other dogs) over
food. The prey instinct can cause dogs to injure themselves (e.g., by chasing cars)
and/or cause them to attack smaller animals and children.
In cats, aggressive behaviors typically involve intercat aggression. Introduction of new
or strange cats into the household, yard, or territory can elicit aggression.
Protection of toys, food bowls, owner affections, and other similar desired things and
experiences may elicit these types of aggressive behaviors. Biting of owners is most
common as misdirected aggression.
Owners can be unintentionally bitten when they try to intervene or prevent intercat
Some cats become aggressive with excessive petting. This is not well understood, and
avoiding excessive petting is the only treatment.
Play aggression can be common in young cats and kittens that have been separated
from other cats at a relatively young age. Cats that are playing with their owners should
be taught not to bite and scratch during this play. If they are not taught how to play
appropriately, they can easily develop play aggression.
Living with the Diagnosis
There are two critical points to living with an aggressive pet: behavior modification and
Behavior modification can take several forms. Avoiding or eliminating situations where
aggressive behavior is displayed, training alternative behaviors, and providing adequate
mental stimulus and physical exercise are all forms of behavior modification.
Avoiding “problem” situations reduces risk to pets and owners alike.
Training provides structure and positive interactions. It tells pets what you want from
Good mental and physical health can help reduce aggressive behavior. Provide your
pet with positive interactions (when it is not being aggressive), mental stimulus, and
physical exercise.
If your pet is aggressive, it is your liability. If you chose to live with an aggressive pet,
you are responsible if it bites you, if it bites others, and if it attacks other pets.
The primary treatment for aggression is training. There are many good behaviorists and
professional trainers.
If you have an aggressive dog or cat, you should research these services in your area.
Speak to friends and find somebody you like and trust. Making an appointment with one
of these experts and reviewing the best options and approaches gives your pet the
greatest chance of a successful outcome.
It is important to realize that, despite your good intentions, you may have triggered, or
unknowingly supported, your pet’s aggressive behavior. It is therefore critical to seek
outside help so that you can receive an objective perspective. Don’t be defensive, since
these professionals do not want to judge but rather are available to help you and your
dog or cat reduce the risk of a potentially devastating injury. Due to the nature of their
work, these experts are usually kind and very understanding in addition to being highly
Head harnesses, gentle leaders, and other non-traumatizing collars and leashes often
provide assistance in training.
Behavior-altering medications are rarely of any benefit and should be a last ditch
attempt as an alternative to euthanasia.
Cats starting to display play aggression should be ignored (stop play immediately and
move away from them) with the first aggressive behavior. Give them a break, a time-
out. Do not restart play behavior until later. They will learn that it is inappropriate to bite
and scratch.
Training, with the benefit of an outside expert. This is the only real treatment that has
any potential for successfully changing the unwanted behavior(s) of an aggressive pet.
Head harness (dogs).
Provide alternate exercise and activities; meet the pet’s social and psychological needs.
Never try to “establish dominance” or treat aggression with aggression. Choke chains,
collars with prongs, and other adverse stimuli are no different than hitting a dog. It is still
aggression and will only cause escalation of the dog’s aggressive behavior, or create an
additional behavior problem such as destructive behavior due to fear.
Punishment of any sort is essentially always counterproductive. Instead, appropriate
actions on the part of humans must be prevention and/or diversion.
Don’t expect others to change because of you and your pet; if you choose to live with an
aggressive pet,
When to Call Your Veterinarian
If your veterinarian treats behavioral problems, he or she should be kept in contact to
direct you with warning signs, goals to achieve, and so forth.
If and when your pet gets itself into trouble (bites, wounds, etc.).
If training is not working and medication is necessary.
Signs to Watch For
Recurrence of problem behaviors/aggression: Often training drops off once you feel the
pet is doing better. This is a common problem with behavioral issues. Consistency and
strict, ongoing training are much more beneficial than partial training. Partial and
incomplete training often teaches alternative aggressive behaviors (e.g., your dog
doesn’t bite anymore, but now it lunges).
Routine Follow-Up
As dictated by your trainer or veterinarian.
If medications are instituted, your veterinarian will give you guidelines for follow-up
based on the drugs chosen.