Even if you are not experiencing an issue with your dog due to aggressive behavior, it is still important for your knowledge as a dog owner to know the different types of drives that are associated with aggressive instincts, and how they relate to each other. Most people will witness all of these behaviors in their dogs at some point.
The drives to focus on when explaining aggression is: Prey, fight, defense, and flight. This chart helps visualize their relationship:
Prey and flight drive are on opposite sides of the spectrum. They are polar opposites of each other and it is rare that a dog would go from one of these actions to the other without first displaying the behavior associated with the drives on the path there. Also, we overlap them to show that sometimes a dog may be showing obvious behavior of one drive, but other times will be in a grey area, showing a bit of both at the same time or otherwise toggling between two. You will not see signs of two drives that are separated by a full drive at the same time. To understand the explanations for each please read the descriptions below:
Prey drive – Prey drive encompasses all the behaviors which originate from the original instinct to hunt, kill, and dissect prey. More specifically this includes tracking, stalking, chasing, biting, holding, shaking, and dissecting (tearing apart). Different breeds were selectively bred to have stronger and weaker instincts within this spectrum, in different combinations, to best suit their task.
An important distinction of this drive is that there is no fear associated with prey drive. In pure prey drive a dog will not show signs of insecurity or signs of feeling threatened. Raised hair, growling, and deep sounding vocalizations/barks are never seen when a dog is in pure prey drive.
For the sake of discussing aggression, usually when dog training professionals state that a dog has "high prey drive" they are referring to the dog's instinct to chase moving objects, people, or animals and bite them. The aspects of prey drive that are related to the discovery of prey are generally lumped into the term hunt drive (which is not discussed in this article).
Flight Drive – Not technically aggressive behavior, this is the instinct to remove self from a threatening situation. This is the most insecure drive and is the opposite of prey drive. Flight drive is the drive a dog will be in if the dog feels he is the prey. A dog that is fighting back is not technically in flight. Flight is total retreat. Some trainer's refer to dogs that are easily triggered into flight behavior as "nervy". If a dog is triggered into flight or is hesitant to specifically engage in certain environments, surfaces, or obstacles he may be referred to as having bad "environmental nerves". It is important to note that flight behavior is a very strong survival instinct that is present in most wild animals. Even the term "bad environmental nerves" incorrectly suggests that there is something clinically wrong with the dog". The truth is that "good environmental nerves", although desirable for most domestic dogs, is actually the result of a genetic suppression of the natural instincts of flight and hesitancy in potentially dangerous situations.
Defense Drive – In its pure form is the instinct to intimidate and use the least contact necessary to drive away a threat to a dog’s self, social status, pups, or anything that the dog feels is important. When a dog bites in defense it is generally with the front of the mouth only and fast with intentions of hopefully driving away the threat while avoiding full contact from that threat. This sums up as, “I’m going to threaten or hurt you, only while you are threatening me or what is very important to me.”
Dogs that show "food aggression" or other resource guarding behaviors are usually in this pure drive. Many dogs will also display this kind of aggression when flight isn't available, such as when restrained at the veterinarians office, toe nails clipped, etc.
Dogs that pursue or otherwise do more than necessary to defend from immediate threat are not in pure defense and are moving into the fight drive category.
Fight Drive – This is reserved mostly toward competitors of "equal" or undetermined status. A dog in fight drive will perceive his target as a threat to something important, but will also go out of his way to continue to inflict injuries with an absolute purpose in mind such as total submission, surrender, or retreat. It is possible for a dog to kill a perceived competitor while in this state. This dog can also toggle back to pure defense drive and then to flight if losing a "fight". In some cases, depending on many genetic and situational factors, a dog may move into a pure prey drive and go through the motions of killing as if the competitor is now prey.
Fight drive may manifest as “territorial aggression” (dogs attack competitors on their territory), during “fear aggression” (I am going to get you, before you get me), and also during "dominance" disputes between dogs or even dogs and people that are perceived competitors for social status and the benefits that go with it (leadership and first right to resources). The term natural aggression is sometimes used in the working dog world to describe a dog that shows pronounced fight drive. Natural aggression is a term that has been derived to be in contrast with aggressive looking behavior triggered by barrier frustration. Although they may look similar, natural aggression is triggered by more primitive instincts to fight a competitor, while barrier frustration has been selectively bred into some breeds of dogs to bark and act aggressively when frustrated or restrained physically from getting to anything desired.
It is important to recognize that humans have domesticated the dog mostly to exploit, to our advantage, dogs' aggressive abilities. Whether it be for hunting, guarding, herding, or military work it is these drives that we as humans desired in them. Unfortunately, in today's modern world, misplacement of these unused and often misunderstood drives will get both dogs and owners into trouble.