Many of us anthropomorphize to some extent about our canines (give a canine human characteristics and/or feelings).   Most agree that a canine feels love, joy, fear, happiness, sadness, etc., just like we do.   Because we share so many common feelings, it is easy to believe that we share the same values and instincts.  However, Mother Nature has programmed canines with a different set of rules than those She provided for us.  Unlike humans, canines do not recognize or understand democracy.  Instead, canines live in a strict hierarchy whereby rank is maintained through displays of posturing and body language. Whether a canine gets first choice of a resource or last, is determined by its rank within the pack.  The alpha (dominant member) of the pack eats first, gets the best place to sleep, and is the one that sets the rules for everyone else.  The beta is given second choice, and this continues down the ladder with the lowest ranking member (omega) getting only what the others have left behind.  Therefore, it is easy to see why most canines take every opportunity to move up in rank.  

Ritualistic aggression is used to maintain the pack hierarchy and is an inherent part of the dog’s psyche.  What we view as canine aggression is in fact a natural competition within the pack for resources such as food, pack rank, the right to breed, or even what a canine might perceive as its very survival. 

Canines are incapable of thinking like us; therefore we must learn to understand the natural instincts and behaviors that dictate their lives.  We need to understand that when we bring a dog into our home, it will view us as members of its pack and will expect us to abide by canine rules.  

We, as pack members often ignore warnings such as posturing, staring, growling, or barking, and do not comprehend their relevance to us.  These behaviors are all subtle tests. If a dog believes he is winning these subtle challenges, he may try more intense challenges in order to further advance his status within the family pack.  Aggression can be as subtle as a disgruntled stare, or as intense as a full-fledged attack. Bites can result from offensive aggression (chase and bite) or defensive aggression (flee and bite.) By not understanding the pre-set rules that canines are born with, we often find ourselves faced with negative canine aggression and in some instances we actually contribute to problematic behaviors. 

 Scientists and behaviorist have done hundreds of studies on canine behavior and the causes of  aggression.  Unfortunately problem dogs usually do not exhibit textbook signs of aggression and in most cases there is more than one form of aggression contributing to the problematic behavior, making it hard to pinpoint the exact cause behind a negative behavior.

 Below are a few of the most common forms of aggression.

Dominance Aggression is centered around pack hierarchy and can be either inherited or learned. 

Some dogs are born with “alpha” or dominant personalities while others learn to be dominant.  Dominance aggression is more common in males than in females and is usually exhibited at sexual maturity (around two years of age.)   Canines born with alpha or dominant personalities are more likely to test their human companions and often require experienced owners with strong leadership abilities.

Because humans are the pack members for most dogs, dominance aggression is usually directed against members of the immediate family and can be provoked in some of the following ways: 

• Waking the dog.
• Moving the dog or ordering him to move from his resting place.
• Staring at the dog.
• Standing over the dog.
• Petting or grooming.
• Putting on a collar or a leash.
• Verbal or physical commands.
• Approaching his food.
• Grabbing the dog's colar.
• Getting too near his favorite person, resting spot, or toy.

The dominant dog can exhibit aggression in many ways.  Below are only a few.

• Standing over or guarding an object or food.
• Direct eye contact (the stare) where the dog exhibits tense rigid posture.
• Growling, baring teeth, snapping, or biting.

The best way to avoid dominance aggression is for all family members to be above the dog in the pack hierarchy.  Those gentle soles that try to make sure their dog knows he is loved often do things that in the dog’s mind make him believe he is above his owner in rank.  A few of the ways we can avoid this happening are as follows:        

• Do not feed a dog until all family members have finished their meal.  This does not mean that one cannot share their dinner with their pet, but that special treats should only be given after the family has finished their meal.
• If an animal is setting in your favorite spot, do not set elsewhere and allow the dog to remain comfortable where he is. 
• When going through a door with you, you should go first or have him to sit and earn the right to pass through the door.
• If one is having problems with dominance, it is not a good idea to let the dog dictate when he is to be petted or play time.  Again, it is a good idea to teach your dog to sit and have him do so before giving attention.

In other words, any time we show our dogs that we are reacting to what they want, they can perceive it as an assertion of their dominance over us.  With dogs that are born with a predisposition to be  “alpha,” winning these subtle challenges can and often does encourage them to try more intense challenges in an effort to achieve the alpha status within their pack.

The best rule of thumb is that we do not do anything for our dog before they do something for us.  For instance, one can have a dog sit before petting it, or being fed.  Basic obedience training is a good idea for all canines, but is especially useful  for those with dominant personalities.

Possessive aggression is also known as sibling rivalry.   This is jealousy between canines and usually centers around competition for a resource such as food, a toy, sleeping place, or even your attention. 

Possessive aggression is a form of dominance aggression and is most often seen as competition within the canine pack.  Owners often contribute to this type of aggression when they fail to recognize a change of status within the pack, or try to place a subordinate dog over the more dominant dog.  Failure to recognize a change of status between the canines can escalate the problem and cause them to continually fight between themselves in order to re-establish pack rank.

The best way to avoid this type of aggression is to recognize and accept the pack hierarchy that the canines have set between themselves.

Fear and pain aggression is defensive aggression and is usually a learned behavior.  Fear of the unknown is inherent in all animals and is the most common type of aggression that dogs exhibit.

Fear of the unknown is usually caused by improper socialization during its formative socialization period.  When a pup is not socialized to the  various sounds, smells, and other stimuli that it will be exposed to as an adult, it can learn to fear those things once it is grown. Because this behavior is learned, it can be more easily treated than some of the other forms of aggression. Fear aggression is recognized as being one of the most common causes of dog bites in children.

Fear aggression is not influenced by gender, and is exhibited almost equally between males and females.  Dogs that exhibit fear aggression often exhibit mixed body language.  For instance, the ears may be back and the tail down or tucked in submission, yet the lips may be curled in aggression.  

When well socialized dogs exhibit this type of aggression it is a good idea to take the dog to the veterinarian and make sure there is no physical cause behind the displays of aggression.  Often times, an animal in pain will exhibit similar behaviors to those exhibited in fear.

Learned fear aggression can be treated by retraining the dog.  One can desensitize and counter-condition the dog using various types of rewards.  Numerous treatments have been successful using positive re-enforcement with rewards of food, touch, and other pleasant things the dog enjoys.  Below is one example of how others have desensitized a dog to fear of men.

• Teach the dog to sit for a treat.
• Identify the exact cause that triggers the aggression.
• Identify the exact circumstances in which aggression is triggered.
• Identify when your dog does not exhibit aggression.
• Do not use punishment to treat fear aggression as it will only compound the problem.
• Treat the condition slowly.
• Desensitize the dog by exposing him to the cause of his fear at a lower level and then reward him for good behavior. 
• Do not stroke the dog when he exhibits fear - it will only re-enforce his belief that there is cause for fear.
• Keep training sessions short (15 minutes) and make them fun.
• If the dog is fearful of men, but not all men, have your dog sit and then have a man that does not scare your dog walk slowly toward you and the dog.  If the dog does not react in fear, reward him.  Reward the dog at various distances when he shows no sign of fear.  Have the man slowly raise an arm and if there is no reaction reward the dog again.
• Keep doing the step above until the man can walk to the dog, raise his arm, and pet it. (NOTE: Do this very gradually.)
• Perform these procedures in an environment where the dog feels least threatened.  Once the man is able to walk up to the dog and pet it, then make the situation slightly more threatening by having him wear a hat, or different clothes, or walk differently. (Again do this gradually.)
• Once the above has been mastered return to the same environment and have a different man approach and repeat the procedure again.
• Once the dog is comfortable with the above steps, take him to a more stressful environment and start over.

The treatment for fear aggression is long and time consuming.  It is much easier to properly socialize the dog when it is a pup than try to desensitize him once he is grown.       

Protective aggression is centered around a dog’s defense of what it considers his and can be exhibited by both males and females. 

Protective aggression can also be influenced either by fear or dominance issues.  Territorial and maternal aggression are both forms of protective aggression.  This type of aggression is inherent and learning enhances the behavior.  Guard dogs and herding dogs are bred to be protective and the behavior is further influenced through either training or operate conditioning. 

Though an owner may not formally train a dog to be protective, those bred for protection often teach themselves.  For instance, if a post man comes to the door and the dog barks, when the post man leaves the dog is rewarded for his behavior - because in the dog’s mind, barking is what made the intruder leave.  Each time he barks and the mailman leaves, this re-enforces his belief that barking scared the intruder away.           

Maternal aggression is influenced by the hormone progesterone that is produced during the female’s heat cycle.  (Maternal aggression often can be mistaken for possessive aggression.)  Most view this behavior as being understandable when there are pups present.  However, there does not necessarily need to be pups for a female to exhibit maternal aggression.  During false pregnancies, a female may choose objects such as  shoes, toys, or even mud balls to serve as surrogate pups.  During a female’s natural cycle of raising a litter, the chosen objects are fiercely guarded by the mother just like pups would be.   The protection of the objects usually stops at the time when pups would be weaned. However, protective aggression can become more serious when it lasts longer than two months. 

The easiest way to avoid material aggression is to spay the female before her first heat. 

Territorial aggression is common in dominant males and can extend to the home, the car, other animals, or even family members.   As set out above, many animals are bred to be genetically  predisposed for protection, and each time they are rewarded for this type of aggression (i.e., the postman leaving), it encourages future protective behavior.

Most  like the idea that their dog is protective of them and their property.  Therefore, one must decide if you want your dog to be friendly with everyone, or protect the property when you are away, or only show protective aggression under certain circumstances.  Different training techniques should be used for each type of guarding ability.

Predatory aggression is the most serious and least treatable form of aggression because the primary intent is to kill the prey.

This form of aggression is genetic and no matter how much we modify the dog’s genetics, it is a factor that cannot be completely eliminated from dogs. (Though some dogs have higher prey drive than others.) 

Though predatory aggression is inherent, it must also be learned.  In other words, all dogs are born with the ability to hunt, but they usually learn how to hunt from their mother and other pack members.   Much of what David Mech describes as group predatory aggression observed in wolves also applies to playful dogs.  However, sometimes a dog ceases to play and the play turns into true predatory aggression. 

Almost all dogs play at prey catching.  They will assume a stalking posture like a wolf, slink up and attack.  Captures are usually made after short chases. (Most dogs give up easily and will rarely pursue a long chase.)  True predatory aggression is usually directed against sheep, rabbits, squirrels, cats, etc., but can also be directed against people.  Young children and older people are the most likely recipients of predatory aggression from dogs.

Any dog can exhibit predatory behavior, but is less likely to do so with things it has been socialized to and raised with as a pup.  Once grown, it is extremely hard to treat an animal that exhibits extreme predatory aggression because there is little if any reward that will outweigh the joy of the hunt and the kill.

Learned aggression is just what it implies. Some dogs have been trained to be aggressive, such as those bred for fighting.   Pain is often used as the motivator in training fighting dogs.  Another type of learned aggression is police dogs that have been trained to be aggressive under specific circumstances. In the right hands, trained or learned aggression is a powerful tool.

Idiopathic aggression is when a dog becomes aggressive for no apparent reason. 

When aggression isn't related to fear, dominance, rivalry, jealousy or another known cause, it is called idiopathic aggression.  There are several breeds that suffer from this type of aggression such as the Pyrananean Mountain Dog, Bernese Mountain Dog, St Bernards, Rottweilers, Dobermanns, and especially blond English Cocker spaniels. Research indicates that this aggression is inherent and therefore, when choosing one of these breeds, it is important to check back at least three or four generations to make sure that the behavior has not surfaced within the line.  Dogs that suffer from idiopathic aggression usually appear to be sweet, loving, well mannered dogs that suddenly for no apparent reason turn on their owners and visitors biting them on the leg, hand, arm, or even face.  Once the sudden rage ends, they will return to their normal loving selves. At this time, there is no known treatment for idiopathic aggression.