Dog is a man's best friend - except when it's standing on your chest and tearing your throat apart with its teeth. Or when the look in its eyes tells you that's what it's going to do if you get so much as one step closer to that steak bone it's been gnawing on the carpet. Not surprisingly, then, animal behaviour experts say aggression is the most common problem that they are consulted about - and it's a nurture AND nature problem.
Dr. James Serpell is an animal behaviour specialist and professor of Humane Ethics & Animal Welfare at the University of Pennsylvania School of Veterinary Medicine. He says that when it comes to aggression in domestic dogs, the causes lie both in the genetic make-up of the pooch, and human training.
"There's no doubt that the genetic inheritance can increase the potential for aggression," Serpell says. "But whether latent aggression is expressed depends on how the dog is taught. You can't easily separate the two."
And you can't put all dog anger down to the same cause. According to Serpell there are a number of well-recognized categories of aggression in dogs. Owners must first find out which category the aggression falls into before they can fashion a cure.
Not surprisingly, aggression often has its roots in instinctive social behaviours that dogs would exhibit towards each other if they were running loose in packs. For instance, aggression can be caused by the urge to compete for status or social rank. Only with a pet dog, human family members are the other members of the pack
"The dog will compete with members of the household," Serpell explains. "It will become aggressive - growl, for example - if touched or groomed, or if its food bowl is approached."
What makes one dog get all touchy about its status is a combination of personality and breed.
"Akitas tend to show [this aggression] more, and Rottweilers," Serpell says. "The so-called refined breeds, lap dog breeds, tend to show it less. It's been 'bred out' in those dogs, to some extent."
Linked to this type of aggression is the category of territorial aggression.
"This is the dog who bites the mailman," Serpell says. "It's aggression towards people or animals that intrude on the area where it lives, or even areas where it is walked on a daily basis. Some people say it's linked to status aggression but some dogs have one or the other only."
Then there is the aggression of male dogs towards other males - just one of a number of male problem behaviours.
"It's a boy thing," Dr. Serpell says. "They also tend to try to escape and roam around, and lift their legs to mark territory. That kind of behaviour."
Hunting dogs and sheep dogs also have a natural tendency towards predatory aggression towards other animals.
"Hunting breeds and sheep dogs show this from an early age," Serpell comments. "For instance, Collies are often the worst sheep killers even though they are used to herd them. The herding comes from the hunting instinct, and some individuals learn to follow it through."
"Protective aggression" is another behaviour that arises in dogs who have been bred for a purpose where aggression is a plus.
"A lot of dogs were valued for their guarding ability, like German Shepherds," Serpell points out. "They show a high frequency of protective aggression, like when someone unexpectedly approaches the owner. This is a defensive behaviour - it's never directed towards the owner."
Aggression may also arise from plain old fear - "white-coat syndrome" at the vet for instance. And just as pain can make a human grouchy, dogs in pain can take out-of-character bites out of their owne
rs' hands. Then a trip to the vet, no matter how frightening, is in order.
In terms of curing the more deeply rooted aggression problems, Serpell says subtlety is the name of the game.
"When there's status aggression, what's happened is that a dynamic has developed where the dog calls the shots," Serpell explains. "The dog demands things like food, attention, walks. So you have to get the owner to recognize this and turn it around: never give the dog things like food, attention or whatever when it demands it. Make it sit first, then give it the walk, or the food. You don't use punishment, which provokes aggression. You have to make it subtle, which confuses the dog."
Rehabilitating this guard dog of its conditioned response comes largely from positive association.
"You must get the dog to associate people coming to the house with something nice, like a food reward," Serpell says. "The dog will then look forward to having people approach it."
But Serpell admits that there are some aggressive behaviours in dogs that cannot be helped - for instance, when dogs suffer from genetic problems like the "rage syndrome" observed in some breeds like the English Cocker Spaniel.
"Rage syndrome looks like an exaggerated form of status aggression," Serpell explains. "It's triggered by the unexpected approach of people when the dog is in a half-asleep state. The dog snaps alert, growls and bites, even people it knows. Then it behaves as if it's very sorry afterwards, as though it didn't mean to do it."
Research has shown that rage syndrome is only associated with certain colours of cocker spaniels: red-golden and black, so that there is probably a strong genetic basis.
"Because the [different coloured] lineages have been separated for a long time, champion dogs, which they were bred from, had this problem. Pure breeding inevitably increases genetic problems because it narrows the gene pool. Some almost have no genetic variation left, and then you can't select out traits anymore."
And unfortunately, there are dogs who have learned to get off on aggression - and often must be put down.
"Dogs who've learned aggression, especially dogs with experience fighting, who are large and imposing, discover that showing aggression causes other creatures to run away," Serpell admits. "They get a kick out of their ability to intimidate, and training them out of this behaviour may be too difficult."