There are a few different reasons that you see aggressive dogs chasing people. Chasing dogs are a particular problem for many bicycle and recumbent bike riders. One reason for aggressive chasing behavior is predatory aggression.
Predation is an aggressive dog behavior. Prey drive or predation is the genetically encoded motor pattern or instinct in dogs that drives dogs to scan for characteristics found in prey animals. These characteristics include rapid movement. When they identify the “prey” they then give chase. Some dog’s eyes are particularly adept at picking up movement. These dogs’ eyes have a visual streak as opposed to an area centralis.
Chasing is an extremely self-rewarding act for many dogs. The chase is the reward in itself increasing the dog’s desire to chase each time. The complete sequence for this aggressive chasing behavior called predation is most often:
• Chase and Bite
• Kill and Dissect
Not all dogs have the motor pattern for the complete sequence. Not all will follow through with a bite, kill and dissect. It is instinct that they are acting on regardless. Predatory drift describes the behavior exhibited when instinct takes over in the chasing dog. It is a purely instinctive response to the passing bicycle rider, recumbent bike rider, walker or runner.
Most likely the chasing dog does not recognize the people taking part in these activities as a person. Dogs recognize people not only by the way they smell and look, but also by the way they move. The dog does not recognize the person as a person when they are riding smoothly by on a bicycle. Walking or running at a fast pace with increased arm movement is not recognizable as normal human movement either. A walkers or runner’s gait and upper body do not offer the dog a familiar look. The chasing dog does not recognize these movements as the movement of a person. A person who is riding a bicycle, walking fast, or running may look more like prey than the person looks like a human to a dog with a strong prey drive. Since some dog’s eyes are particularly adept at picking up on the movement, and these dogs may have a strong prey drive the aggressive chasing behavior bubbles to the surface and takes over.
Not all dogs will exhibit the whole sequence. Some dogs will only exhibit the eye, stalk and chase. Whether the aggressive dog expresses the whole sequence or not does not matter. There is a potential for a problem if you are a bicycle rider, or recumbent bike rider, walker or runner, and the dog gets to the stalk and chase. Just the chasing part of the sequence is hazardous for the bicycle rider. There could be an accident if the dog crosses the bike’s path or runs into the bike.
So what can be done about chasing dogs? The outdoor enthusiast has a few choices in deterring the chasing dog or in finding a dog repellent. We believe it is best to offer a dog deterrent signal that is loud, repulsive and annoying enough to shake them out of their instinctive chase. The key is to make it repulsive, uncomfortable and disagreeable, for the dog to continue so that the dog remains at a safe, non-threatening distance.