We may think that predatory behavior is something dogs' ancient relatives needed to survive and that now it's redundant and all but forgotten. But that's not true. All domestic dogs possess an innate prey drive and associated sensory and motor skills to act on this motivation.
But activation of prey drive is more complicated than a dog seeing something he considers prey and then chasing it. Below is a list of factors that come together to form the behavioral end point that is fully operational predatory behavior: Breed tendency. Some breeds are more highly motivated to chase prey than others
Experience. Success is a potent reward and will instill lasting memories.
Opportunity. The freedom to act and a prey-containing environment.
Motivation. That aspect of internal processing that propels an animal into action.
Social facilitation. The presence or absence of other pack members.
The Two Phases of the Hunt
The appetitive phase, classically fueled by the need to eat. Hunger prompts dogs to search, find and catch prey. In searching for prey animals, dogs use just about every sense they possess. Working from memory, and with the aid of mental maps, they systematically comb their territory searching for leads. Olfaction (sense of smell) is extremely important at this stage of the hunt and dogs are impressively equipped in this respect, having a sense of smell about 100 times more sensitive than our own. Vision becomes the primary sense once the prey is sighted and the movement of the prey triggers a well-strategizsed and well-choreographed chase. The precise mode of the final coup de grace depends on the size of the pack and the prey animal itself.
The consummatory consume phase. This entails eating, or rather devouring, of the kill. Dominance and rank within the pack determines which dog has priority at the feast.
Domestic dogs are difficult to study with respect to their predatory dynamics because they dwell in their owners' homes in an unnatural situation. Predation is not necessary for their survival. We may see a German shepherd chase a squirrel up a tree or a collie chase sheep, but such observations only provide a glimpse of the full picture of their predatory capacity. Because of such limitations, most of what we assume to be true of domestic dogs is gleaned from studying wolves or wild dogs, in which hunting is still the way of life.
It appears that dogs would normally, but not always, hunt in packs. Large prey animals require the cooperative approach, while small prey animals can be dealt with by means of a one-on-one approach. Hunting groups typically comprise six to ten pack members of either sex and of suitably mature age.
Left behind are nursing mothers and/or surrogate minders for the pups. Wandering over a large area of territory and following scents, one pack member finally picks up a trail and the others follow it toward the target. On catching sight of the prey animal, the pack normally attempts to encircle and cut off the prey while chasing it down. Stamina and relentlessness, as opposed to speed, are the dogs' main weapons during such a pursuit. Whichever way the prey turns, a dog is there to block its escape, redirect its course, or begin the attack.
One attach strategy involves several dogs attaching themselves onto the front end of the beast while others disembowel it from behind. For smaller animals, the neck of the prey animal is the primary focus. Wild dogs sometimes slow their prey down by hamstringing it (biting through the Achilles tendon) whereas wolves tend not employ this mode of attack. It is not clear how domestic dogs operate but if street attacks are anything to go by, dogs are hamstringers, too.
Having caught and killed the prey, the victors gorge themselves. Because many pursuits are unsuccessful, and the pursuants can never be sure when the next meal will appear, they make sure to get their fill. Some dogs leave the scene with an engorged stomach so that they can regurgitate food for absent pack members when they get back to the den area.
The Domestic Situation
Domestic dogs, as a whole, are less well equipped for hunting than their wild cousins who depend on their ability to fend for and feed themselves.
That said, the predatory instinct has been preserved to some extent in all dogs and has been cultivated and refined in certain breeds. The working behavior of sporting breeds is based almost entirely on customized predatory instincts. For example, pointers sniff out and point toward game, retrievers find and retrieve shot or injured prey with their "soft mouths," and spaniels locate and then leap, or spring, to flush out quarry.
Breeds most well known for having high prey drive are contained within the herding group. Herding behavior provides the best example of the predatory behavior at work in modern-day domestic dogs. From the stalk to the crouch, creep to the running and nipping, shepherd dogs almost have it all, except the final consummatory phase, which has been agonizingly culled out of their predatory repertoire for centuries. Though actively suppressed, this final phase of the predatory sequence is still genetically encoded in the various members of these breeds and re-emerges from time to time.
Predatory Behavior at Home or in the Street
Pet dog owners who simply want a family friend may not care for all this talk of predatory behavior because their dog will not have to hunt or kill for his food and they have no desire to have their dog herd sheep or retrieve game. Nevertheless, predatory behaviors are still there in their dogs, to a greater or lesser extent. Below are a few examples of dogs' predatory behavior at work in the domestic setting.
Chasing cars, bicyclists, skateboarders
Chasing children running alone or together in a group
Shaking (to "kill") a stuffed toy or slipper
Group aggression - when two to five dogs in a "pack" encounter a moving prey facsimile
Rare attacks on too easily accessible, unattended, flailing newborn human infants
Chasing tennis balls and Frisbees
Biting or nipping people in the heels/calves/thighs as they run or move away
Terriers digging in the back yard
Retrievers "herding" shoes or other objects into one area
Border collies herding people to stop them from leaving a group
Dogs barking in vehicles or barking at cars en route
Trying to train the predatory behavior out of a dog is like swimming upstream. You might make some progress if you work hard for a while, but you will be back to square one the moment you stop. It is better to simply acknowledge that predatory behavior is part of dogs' genetic nature (as it is our own), to live with it, channel it appropriately, and take steps to avoid unfortunate accidents. While predatory behavior spin-off can be entertaining, in the form of ball chasing, or amusing, when toy dogs' predatory ambitions exceed their capabilities, it is far from entertaining or amusing in larger dogs when directed toward people. The moral of this story is know your dog, recognize predatory behavior for what it is, and take whatever steps are necessary to prevent unfortunate accidents.