Many behaviors associated with aggression are threat displays. The most common aggressive threats are growling or barking, a stiffening of the body, baring the front teeth in what’s called a “tooth display” and giving an offensive pucker which is when the corners of the lips (commissure) are pushed forward so that the mouth becomes O-shaped. Another behavior associated with a dog with an increased likelihood of behaving aggressively is when the dog’s eyes change from the usual warm liquid look to appearing icy cold and hard. However, many dogs do make threats with one or more of these signals without ever causing injuries.
Ironically, these threat displays can function to thwart serious aggression, which is why many of them occur without ever leading to injurious behavior. By showing their weaponry or signs of strength, dogs are communicating that it would be unwise to challenge them. Two or more dogs can assess each other, and often one or more decide that to proceed would be unwise. Dogs can use these signals to communicate the equivalent of “I have teeth and I am willing to use them” which is sometimes enough to convince another dog not to tangle with the first dog.
Dogs who give threat displays are sometimes willing to avoid aggression depending on the other individual’s response to their display. That is why dogs who never give any warning before behaving aggressively are the most frightening and potentially dangerous. Dogs who attack in full stealth mode with complete silence have no intention of avoiding aggression and are the ones most likely to deliver uninhibited, seriously injurious bites.
Similarly, the most scary and dangerous dog fights are the silent ones in which all the dogs’ energy is focused on the attack rather than the loud ones in which a lot of energy is going towards barking and growling. They are the ones that are most likely to lead to serious injuries or even death. Much less likely to cause serious damage are the ones that sound, to use a phrase that is descriptive if not pretty, “like dogs in a blender.” These are full of sound and fury, signifying nothing. It is ironic that the threat displays indicating that injurious aggression may follow can function to lessen the probability of physical confrontation and potential injury.
The vocalizations and visual displays that often accompany dog fights are a form of communication. As long as the dogs are attempting to communicate with one another, there is some possibility that they are seeking to end the conflict, and that there is a chance of arriving at a peaceful solution. If the dogs have no interest in working out the conflict or to de-escalate the aggression, then the dogs are most likely serious about injuring each other. That is why the most dangerous dogs who are aggressive are those who attack in a stealthy way. They are like hit men: “This is nothing personal; it’s just business.” Quiet fights and quiet attacks involve individuals who are most likely actually trying to cause injury, rather than trying to reach a resolution.