by Alexandra Semyonova
Probably most people recognize that every dog breed results from human manipulation of inherited physical traits.
Until recently, most people probably also recognized that much dog behavior is also a result of manipulating inheritance: if you want to do sheep trials, you get a border collie. If you get a beagle, he will likely become instantly deaf to your calls if he picks up a scent to track.
But after discussion started about perhaps banning breeds who often attack and kill, defenders of these breeds began to dispute the heritability of any kind of dog behavior.
Only when behavioral inheritance is understood, beginning with basic biological concepts, can we have a clear and honest discussion about aggression in domestic dogs. First we must understand the relationship between “physical conformation” and “behavioral conformation,” which may be seen as opposite sides of the same coin.
“Physical conformation” describes how a dog has been bred to become physically shaped specifically for the task we want him to perform. The purpose-bred dog’s body––brain, skeleton, muscles, and metabolism––will be different from those of other dogs. The dog will feel physically comfortable doing the job, whatever it is.
The border collie is physically designed for the stalking stance and for switching easily and often from standing to lying down to standing again. A greyhound enjoys sprinting, with a deep chest that easily provides enough oxygen to the dog’s muscles to fuel a burst of high speed. The same deep chest means the greyhound cannot run marathons because the deep chest prevents a greyhound from losing heat efficiently.
The greyhound’s brain has been shaped by selective breeding to steer the legs in a gait that provides maximum speed in a sprint. The unique composition of a husky’s skeleton, muscles and brain enables a husky to pull a sled with a different gait, and to sustain a brisk pace for long distances.
The greyhound runs by leaping, the husky by pushing, always with one foot on the ground. Each dog is genetically wired to use the specific body the dog has.
Selecting for performance
Dog breeders have for centuries selected for particular traits by simply watching how a dog performs. They have bred dogs for specific tasks by removing the dogs who perform less well from their breeding stock. Sometimes they will cross in a dog breed they think will add traits to perform the task better. Breeders select for performance without always knowing exactly which traits they are breeding for. For example, until recently no one realized the husky was being bred for a particular heat economy; they just chose the dogs who kept running the longest. Eventually, successful breeders produce dogs who are physically shaped to do the dog’s task better than any other dog, no matter how well the other dog is trained.
“Physical conformation” leads to “behavioral conformation.” First of all, each dog’s brain is genetically predisposed to grow to efficiently direct the body it is born in. Then the dog’s brain adapts itself further to the body it is in as it grows in the developing puppy. There is no gene for running or stalking, but there are genes that give a dog four legs and make those legs longer, shorter, more or less flexible, and so forth. It is because of the action of the genes that confer differently shaped bodies and brains that the pointer enjoys pointing, the border collie stalks and stares, the Newfoundland floats in cold water, and so on.
Selecting for aggression
Just as we cannot make a dog into something the dog has no genetic capacity to be, we cannot prevent a dog from being what the dog is genetically predisposed to be. Because inherited postures and behaviors are suitable for the body and brain the dog was born with, they are internally motivated and internally rewarded: they feel good. This means that inherited behavioral traits are practically impossible to extinguish by manipulating external environmental stimuli.
In breeding dogs to perform certain tasks or have a certain look, humans often select (sometimes inadvertently) for abnormalities in body and behavior. We do this by looking for mutations and then breeding for them, or by crossing breeds to get combinations of traits. to speed the process up. A clear case of this is the old English bull dog, who can hardly walk, hardly breathe, and cannot be born except by Caesarean section. The bull dog has also been crossed into other breeds by people who wanted to increase aggression in a breed without waiting for mutations to appear.
There is such a thing as normal aggression in dogs, as in all animals. Maternal defensiveness, territorial defense, and predatory behavior and depend on different neuronal and hormonal mechanisms, and are all normal coping responses. These dog behaviors have been accepted by humans in the process of domestication, as long as the behaviors can be foreseen.
But abnormal disinhibited behavior is not functional, and it is unpredictable. Although high arousal and sudden attack can be functional in certain environments, this behavior is pathological in a safer environment, where a high level of arousal and aggressiveness are not necessary and only lead to unnecessary attacks and injuries. Research implicates the frontal cortex, subcortical structures, and lowered activity of the serotonergic system in impulsive aggression in both dogs and humans. Impulsive aggressive behavior in dogs seems to have a different biological basis than appropriate aggressive behavior.
Kathelijne Peremans, DVM discovered this by studying two different populations of impulsively aggressive dogs. Each dog had executed one or more attacks without the classical preceding warnings, and the severity of the attacks was out of all proportion to environmental stimuli. Peremans found a significant difference in the frontal and temporal cortices of these dogs, but not in the subcortical areas, compared to normal dogs. Peremans also found significant dysfunctions of the serotonergic systems among these dogs. Serotonergic dysfunction has been widely shown in many different species to be connected to abnormal, impulsive aggression.
Peremans studied dogs of various breeds, selected purely on the basis of their behavior. Peremans was not interested in implicating any particular breed, but rather in finding the mechanism behind the behavior in any dog it occurred in. She found that all of the dogs with a history of abnormal impulsive aggression shared the same physical abnormalities in the brain. The gender of the dog made no difference. Neither did whether the dog was castrated or spayed.
Peremans left open the possibility that we will later find other physical factors that contribute to abnormal impulsive aggression. For example, the adrenergic system may also play an important role.
Heritability of behavior
Another researcher, Linda Van Den Berg, investigated specifically the heritability of impulsive aggression among golden retriever, a breed rarely involved in fatal and disfiguring attacks. The goal was find out whether impulsive aggressive behavior was inherited in those few golden retrievers who exhibit it, and if so, to isolate the gene responsible for the behavior. Van Den Berg found high heritability of impulsive aggression, but did not succeed in isolating the responsible gene(s).
The heritability of abnormal aggression in certain breeds of dogs can no longer be denied. The bodies of these dogs have been selected to execute a killing bite more efficiently than other breeds. These dogs share physical conformation to the task of killing, including exaggerated jaw muscles, heavy necks and shoulders, and body mass that makes defense against an attack much more difficult. Among people who want dogs who can kill, these are the breeds of choice because they are physically more fit for it than other breeds.
But breeders also selected for behavioral conformation. To perform well, a fighting dog had to attack without provocation or warning, and to continue attacking regardless of the response of the other animal. Bull and bear-baiting dogs had to be willing to attack in the absence of the species-specific signs that normally provoke aggression, responding to the mere presence of another animals, and not stopping in response to external stimuli. The Dogues du Bordeaux used to guard extended farmlands in France, the Boerbulls used similarly in South Africa, and the fugitive slave-chasing dogs of Latin America, such as the Dogo Argentino and Fila Brasiliero, all were selected to specifically for a propensity to kill.
As they selected for performance, breeders could not know exactly which physical changes they were selecting for. But research now shows that selection for aggressive performance includes consistently selecting for very specific abnormalities in the brain. These abnormalities appear in many breeds of dog as an accident or anomaly, which breeders then attempt to breed out of the dogs. In the case of the aggressive breeds, the opposite occurred. Rather than excluding abnormally aggressive dogs from their breeding stock, breeders focused on creating lineages in which all the dogs would carry the genes causing them to reliably exhibit the desired impulsive aggressive behavior.
“That aggression is not heritable is not tenable”
Now that we know exactly which brain abnormalities the breeders of fighting dogs have been selecting, the assertion that this aggression is not heritable is no longer tenable. It is also not tenable to assert that not all the dogs of these breeds will carry the genes that make them dangerous. These genes may occasionally drop out through random accident, just as golden retriever may acquire the genes to be impulsively aggressive. But the failure to have these genes, in the aggressive breeds, is just that––a failure. It is therefore misleading to assert that the aggressive breeds will only have the selected genes as a matter of accident, or that most of them will be fit to interact safely with other animals and humans.
As in the pointer, the husky, the greyhound, and the border collie, the genes of aggressive breeds have been selected so that certain postures and behaviors just simply feel good. These dogs will seek opportunities to execute the behaviors they have been bred for. Because these behaviors are internally motivated and rewarded, they are not subject to extinction. Learning and socialization do not prevent these dogs’ innate behaviors from appearing.
Environments such as the fighting pit, confrontations with tethered bulls and bears, and the pursuit of escaping slaves, for which these behaviors were selected as an adaptive response, are so extreme that there is no appropriate context for these behaviors in normal life. Functional in the pit or facing the bull or bear, these behaviors must, in all other contexts, be called pathological. Because the behavior selected for was impulsive aggression, by definition this behavior will always emerge suddenly and unpredictably.
Speculating in favor of the aggressive breeds, suppose that human artificial selection will fail as infrequently in the aggressive breeds as it does in the golden retriever. Van Den Berg found impulsive aggression in approximately one out of a hundred golden retrievers. If behavioral selection fails comparably often in fighting breeds, there is only a 1% chance that their keepers will not endanger others in their surroundings.
Can aggression be bred out?
Can impulsive aggressive behavior be bred out of fighting breeds?
The fiction that, for example, the American Staffordshire terrier is a different dog from the pit bull, just because the breeding has (also fictionally, by the way) been going on separately for several decades is just that: a fiction.
The Russian researcher Dmitry Kontanovich Beljaev reported that he had bred fear out of foxes in only eighteen generations, but impulsive aggression is a more complex response and much more dangerous to live with while you try to breed it out. Further, Belyaev’s foxes were bred under laboratory conditions, where there was absolute control over not having the wrong genes creep back in again.As Belyaev bred his foxes into the petable creatures he wanted, they began to have an increasingly floppy-eared mutt exterior. Belyaev’s discoveries suggest that the interface of physical and behavioral conformation mean it is not possible to breed out the impulsive aggressive behavior of fighting dogs while retaining their shape and appearance.
Form follows function: one cannot have a dog whose entire body and brain are adapted to executing the killing bite, without having a dog who will execute the killing bite.
Jamaka Petzak says
It is truly evil and frightening what happens when people try to play god.
Jackie Phillips says
Breeders do it every single day, day after day, month after month and year after year without a care in the world, and that is why purebreds are so messed and dogs die of cancer at six years of age and no one bats an eye.
As a breeder, I do indeed select for desirable physical and temperamental traits, allowing me to produce functional serviceable animals. As to dying at age 6, in 30 years of doing this, I have not had that unfortunate experience with my own dogs, although it is true that dogs, being living creatures and not manufactured products do sometimes die young-mixes as well as purebreds.. My generations of working Search and Rescue, Police and service dogs generally live into their 13th to 15th year, which is a reasonable and natural lifespan for a canine of this size ( 58-80 pounds). What is truly sad is how uneducated poorly informed opinion is espoused as fact. If you can scientifically demonstrate the genetic basis of a particular cancer and show with *any* legitimacy how purebreds are susceptible to it to a greater degree than mongrels, I would be interested to read such a study. But you can’t. You just spout nonsense masquerading as truth because you ” Read it on the Internet.” Breeders like me are proud of what we do. My dogs have saved lives, helped solve crimes, and made many people very very happy to own them. Whenever we read nonsensical drivel like this we will reply with fact. Not going feel ” ashamed” of producing wonderful animals. Proud of it. Will fight back. Get used to it.
This is the old theory of “nature versus nurture” and it clearly argues that genetics wins and plays a far greater role than upbringing. While the flight response in foxes is a matter of controlling a non-domesticated animal and making it more domesticated, when dealing with animals that have already been domesticated for centuries upon centuries, it’ s a complex argument that training of impulse control is of no use in dogs that were physically built for aggression. Take for example a dog that we can agree is used largely as a police dog, which is the German Shepherd. This breed has many sub-gene pools. We have working lines from Schutzhund that breed for high prey drive and fighting drive, but also a great deal of control. We also have lines that can herd sheep in the “tending” style, or the style of a living fence, and yet we have other gene subpools within the breed that produce mildly mannered dogs suitable for leading the blind as guide dogs. So this one breed alone, although it remains one single breed, demonstrates that it’s not the breed as a whole that has certain tendencies, but rather, specific gene sub-pools within the same breed that have certain tendencies. Yet another example is the KPNV Belgian Malinois versus the Turveren, or other varieties of Belgian Sheepdogs. I would argue they are the same exact breed except for coat color. However, I can easily show you the difference in temperment, aggression, prey drive level and impulse control amongst these two varities of the exact same breed. So here again, the gene-subpool matters, not the breed itself.
A lesser example, is that there is the hunting or working Golden Retriever and the “show’ Golden Retriever. Here again is yet another example within the SAME breed,not switching breeds, that shows a greater variability in behavior. So I would argue, that while overall certain breeds will exhibit more aggressive tendencies, proper ownership and management, has a far greater role. I would also argue, based on my example the German Shepherd alone that aggressive tendencies, dominance, impulse control, trainability level and overall behaviour show greater variation within the same breed than across breeds, but on the gene sub-pool involved. Therefore how can you argue that some breeds are genetic killing machines, if you can’t even make the argument within the same gene subpool of the same breed! Sorry, the general idea is correct, but it falls apart in the details.
Merritt Clifton says
The above appears to not only overlook but deliberately ignore that the alleged “variability in behavior” taught to German shepherds and golden retrievers builds on the same instinctive behaviors and physical attributes of the dogs, and in either instance requires them only to do in a more focused manner what they are already inclined to do. This is also the tendency of pit bulls and related fighting breeds, who historically have been bred to tear other living beings apart in the fighting pit, but are equally capable and frequently inclined to do it right in the comfort of their people’s living room.
Peter Hamilton says
Pit bulls and other fighting breeds do not appear to always “do it right.” Their genetic disposition makes them unpredictable. During my investigations of dog fighting even the dog fighters admitted that they would not leave their pit bulls alone with kids and “pets” because they could “snap” at any time. The failed socializing of pit bulls by the British Columbia SPCA has resulted in at least one attack and death of an innocent animal companion, out for a walk.
Zoey Jackson says
There is a huge difference there, and quite frankly a pretty poor comparison.
The point is that these behaviours are ingrained rather than taught – and unlike many other breeds that do live quite comfortably side by side with humans, when base instinct does come through, the consequences are more annoying than dangerous.
Shepherds and retrievers have had roles that, guess what, traditionally revolved around shepherding and retrieving – the need to attack unprovoked was never a part of their makeup and, if anything, was discouraged. If it wasn’t, then you’d have a dog that was more of a hindrance than help in the environments they were used.
All dogs have the potential to attack; and many dogs pose an ongoing risk to a lot of non-human and non-canine beings – but the point is, on the whole, they were bred to work with humans and to live harmoniously with other dogs – but this is not the case for dogs bred for fighting, baiting or to simply rip apart a human tried to run away.
THAT is the point here. Yes, all dogs have been bred to hone certain behaviors and traits but the big difference here is, when a collie reverts to instinct, you have an agile and focused dog that will herd; a retriever that will dive into water and bring you an array of already dead birds and rodents; a German shepherd that will guard and yes, possibly attack if it’s land or it’s herd is threatened – it still needs provocation and ques to do so.
But when a fighting breed reverts – or rather snaps – you instead have another dog or a human, ravaged.
That is the big difference – and also, is the huge problem we have.
Dog parks have turned from a nice idea, to a dangerous mix. With every second person owning one of these status dogs that are sometimes nothing more than a weapon, and often with people who have watched an episode of two of Caesar and now see themselves as the next big dog whisperer, despite knowing very little about canine behavior at all — what you have is a very lethal combination. Idiots who think possession guarding and aggression is ‘cute’, and that mounting other dogs, ignoring clear warning signs from dogs who want to be left alone and being an all around nuisance is “just showing dominance” and is fine and dandy – turning off lead dog parks into, basically, a potential fighting pit.
I very rarely visit these parks any more because of the nightmare mix of stupid people and dangerous dogs. If I do go, it is when I know the other people and for my own dogs to socialise with the humans and canines they seem to enjoy the company of.
Any dog with a century-long lineage of being bred to fight is dangerous. Burying your head in the sand about it just makes it worse.
It still comes down to an individual dog’s temperament and the intelligence or knowledge of their human. Dogs are as different from each other as people are. Some of the best baby dogs I’ve ever seen were mastiff breeds and some of the most aggressive ones I’ve encountered were retrievers and poodles. Yes, I agree that genetics do play a big part in determining a dog’s temperament, but the responsibility should fall on the people who are breeding them and the owners who are allowing them to be in triggering situations that are the problem. I’ve only had one dog who would unpredictably bite. The rest would, like all dogs everywhere, bite when provoked, defending, or otherwise triggered. If they are going to use studies such as this to enact laws, then I hope the laws they enact will regulate the BREEDING of dogs. Make it illegal to breed dogs that have the brain anomaly this article was talking about. Also, any breeding of dogs that cannot survive, or successfully reproduce, without medical intervention should be stopped as well. That’s just cruelty.
Even pit advocacy has admitted this. DIANE JESSUP, pit bull expert, breeder, former ACO, FOUNDER of pit advocacy?
“Jessup, the animal control officer in Olympia, uses two pit bulls to train police and animal control officers on surviving dogs attacks.
Unlike dogs who are nippers and rippers, her pit bulls are typically “grippers” who bite down and hang onto their victims.”
Jessup believes that much of dog behavior comes from their genes. “I truly believe that a dog is about 90% genetics,” says Jessup.
on protection sports
This difference in “sheepdog versus bulldog” mentality in a trainer is best understood when training the “out!” or release command. It is common practice for those training shepherds and sheepdog types to use force such as hard leash corrections or electric shock to get the dog to release the sleeve. Sadly, I had one young man come to me because a club trainer was slugging his little Am Staff bitch in the nose, till she bled, trying to get her to release the sleeve. She would not! And of course she would not! She was a good little bulldog, hanging on for dear life, just as her bull and bear baiting ancestors of old did. She was a super little gripping dog, who took the pain she experienced as just “part of the job” once her owner set her upon the sleeve. And this is the response from well bred pit bulldogs—to ignore pain while gripping. It is, after all, what they are bred for!
Very interesting article; thank you very much! I however agree with Alexander in that there are some flaws in the argumentation as for the inherent and permanent danger in breeds that were once selected for dis-inhibited aggression.
Yes, it took 18 generations to create a specific trait, such as domestication in wild foxes, but I argue that losing a specific trait is much faster. I work with sheepdogs (border collies and other breeds) and they do not “revert” to their ‘natural’ state of herding skillfully and focused. On the contrary, it takes very conscientious breeding in every generation to keep this trait, and it only takes a couple of bad matings to lose it. After just a few generations of breeding from only mildly talented sheepdogs, even border collies revert to “standard dogginess,” herding not much better than a Malinois and effectively being useless at a farm. Throw in a few agility dogs and show line border collies in the mix and in no time you have border collies who show no interest in sheep at all,
Several of my breeder friends are trying to bring back the herding talent to for example Beauceron, Malinois, laekenois and rough collies, and it’s far from certain they will manage, although it’s just a few generations back. Dogs don’t revert to the extremes; they revert to standard behaviour, which does not include the “abnormalities” you talk about in your article. I would therefor argue, based on my experience from sheepdogs, that you can breed these extreme traits out of the breed.
It would seem to me that if the aggression trait was so easily lost, than there would not nearly be as many fighting breed-related deaths as there are.