Countless times throughout my more than three decades as a veterinarian, people have expressed their fervent belief that how a dog behaves is due to how that dog is raised. People are convinced that if a dog ever tries to bite, it’s because the dog was mistreated at some point or someone is doing something to antagonize the dog or maybe the dog’s owner isn’t raising the dog right (just as when a child misbehaves, people are quick to think that it’s the parents who aren’t doing something right).
I absolutely agree that behavior (both dog and human) is going to be impacted by the way an individual is treated, especially if there’s any mistreatment or abuse. But I don’t agree that environmental factors have the greatest impact on behavior. In my humble opinion, that honor belongs to DNA. As it’s frequently underestimated just how pivotal genetics is when it comes to our temperament and behavior, this book is an attempt at refuting that misconception.
Whenever we examine just the exterior of something, it’s not easy to understand or grasp the hidden, inner workings that go on beneath that exterior. This is as true of living creatures as it is electrical and mechanical devices. For example, there’s so much more to humans than simply our skin, hair, eyes, nose, mouth, and the rest of what constitutes our external appearance yet, those are what we inevitably focus on whenever we interact with one another. Those are the features we see. What we can’t see and, as a conseqence, what we don’t tend to think about are the millions of individual cells inside our bodies, the miles of blood vessels and nerves, the heart that steadily pumps, the brain that persistently thinks, in addition to all the other organs that diligently perform their duties completely hidden from observation. Though the internal aspects of ourselves may be hidden from view, they’re absolutely vital if we’re going to define who we are as living, breathing beings. Yet, except for when one of these systems fails or causes us problems, they’re invariably out of sight and out of mind.
In the exact same way, it’s convenient and easy to primarily focus on environmental factors whenever we try to explain or evaluate behavior. The external circumstances of our lives, such as our families, socio-economic status, education, friendships or lack thereof, are always the first things that come to mind when we attempt to understand what factors have influenced our behavior. Our personal history is naturally going to be what’s foremost in our thoughts simply because that’s what we’ve experienced and what we know. It rarely if ever occurs to us that something we can’t see or experience is what actually has the greatest influence on our personality and behavior.
That most potent of invisible forces is DNA. DNA is typically so far from our thoughts that It’s actually more inaccessible than our internal biology, which can at least be accessed through various types of imaging (such as x-rays and MRIs), blood tests and surgical procedures. Yet, our DNA defines us as certainly and completely as water defines the ocean.
It’ll help us in our efforts to understand the influence of genetics in ourselves if we take a moment to examine the genetic reasons why dogs bite. Before I begin, though, I’d like to clarify two important points. First of all, even though I’ll be making a lot of general statements about the traits of certain breeds of dogs, it’s definitely not my intention to malign any particular breed. These general statements are based on thirty-plus years of experience as a veterinarian and unfortunately, not all of these statements are going to be complimentary. I’m just calling it as I’ve seen it. I don’t have a personal vendetta against any one breed or another but I have no choice but to state the facts as I’ve come to know them.
Secondly, though it’s my contention that genetics is the greatest predictor of personality and behavior, I’m not negating or discounting the fact that environmental factors influence and impact our lives. Genetics and environment are both involved in the making of any individual but the extent to which they influence personality and behavior has yet-to-be completely illuminated. This is a book about how DNA serves as a template for our individuality. If we can eventually accept that fact, it’s going to be much easier for us to accept ourselves and others as we are. With those two points clarified, let’s look at the genetic causes of biting in dogs.
One day, when I was at work at my veterinary clinic in southern California, two police officers banged through the front door cradling a severely injured Labrador. The dog’s owner had gone berserk for some reason and had beaten the poor dog with a baseball bat. Astonishingly, the dog wasn’t killed but he did have a broken leg in addition to many other traumatic injuries. It was heartbreaking because the dog was so traumatized and terrified of people (rightly so!) that he’d immediately cower, start to tremble and even urinate on himself if someone moved to suddenly to touch him. Yet, in spite of all the abuse he’d experienced and all the procedures we had to put him through as part of his recovery, he never once tried to bite. What we eventually noticed was that he actually loved being petted and, once he got past his initial trepidation as to whether someone was friend or foe, he’d almost melt, getting all doe-eyed and thumping his tail while someone gently stroked him. He simply had to get past the fear of that first touch. Yet, there’s no doubt in my mind that if that Lab had been some other type of breed, a breed that was more sensitive, fearful or aggressive, we would definitely have seen some growling and snapping going on.
Dogs bite for a variety of genetic reasons: most originating with the dogs’ breed and temperament. For example, dogs that are overly fearful typically use biting as a way to protect themselves. Fear-biters always anticipate the worst and they believe wholeheartedly in the Vince Lombardi adage that the best defense is a good offense. They’re convinced that they’d better get you before you get them! Fortunately, most fear-biters only bite when their space is invaded or when someone tries to mess with them when they don’t want to be messed with.
Other breeds of dog that born with a strong inclination to bite are the breeds that were bred specifically to be protective and aggressive. Biting, for these dogs, is simply a part of their job. It’s what they were bred to do. Their motto is bite first and ask questions later! Rottweilers, Mastiffs, and German Shepherds are examples of dogs that have been bred specifically to guard, attack and even accompany soldiers into war. These dogs aren’t fearful but they’re not especially friendly either. They’ve been bred to be leery and suspicious of strangers and, as a result, they can be quick to bite in any situation that is stressful or unfamiliar to them.
Herding dogs, such as Australian Shepherds, are dogs that have been bred to bite and use their teeth as a means to defend and protect the sheep, goats and cattle in their charge. Biting is not only a tool for these dogs, it’s the ultimate in tough love in their efforts to control and manipulate the herd.
Terriers are a class of dog that were bred specifically to hunt and kill rabbits, rats, foxes or any other animals that were deemed to be problematic to humans. As a result, terriers have an extremely sensitive “attack” instinct that’s easily triggered whenever they’re challenged, stressed or stimulated by what appears to be a prey running away. Until it was made illegal, Pit Bull terriers were bred in England to attack huge animals, such as bulls, bears and boars, in a bloody sport called “baiting.” Pit Bulls were purposely bred to have sufficient stamina and strength so that they could latch onto an animal and not let go until that animal was defeated or dead. That’s why Pit Bulls can be so dangerous because, if they do decide to bite, their breeding causes them to hold on and not let go. Regrettably, there are unscrupulous individuals who secretly breed aggressive dogs in illegal “to the death” dog fights.
There are other reasons why dogs bite. Biting is a normal part of the pack dynamic in a group of dogs as they figure out the pack’s pecking order. Dogs bite when they play with one another and when they join together to take down a prey. Biting is a normal and expected part of being a dog and pet owners need to understand that many dogs will bite at some point or another even if they are a nice and friendly dog most of the time.
Now that we’ve looked how DNA and genetics impacts the tendency to bite in dogs, let’s look at an important study that illustrates how intensely DNA impacts the tameness and domestication of animals. I was fascinated and amazed when I first read the March 2011 National Geographic issue called “Designing the Perfect Pet.” The article describes in detail the half-century research project that was conducted in southern Siberia by a biologist called Dimitry Belyaev.
Belyaev began his experiment with one hundred and thirty wild foxes that he purchased from various fox farms in Siberia. The objective of the experiment was to figure out just how long it would take to strategically breed wild foxes until they finally became tame and domesticated. With each successive litter, Belyaev carefully selected the pups that were the least fearful of humans and he’d breed those foxes to one another. After only nine generations, Belyaev had produced a group of foxes that were so thrilled at the presence of humans that they’d whimper, whine and wildly wiggle their bodies and wag their tails in happy anticipation of being petted by a human.
Belyaev, though, also wanted to look at the impact that environment might have on the wild foxes. To that end, he selectively bred a line of human-aggressive foxes that were so agitated by humans that they’d either recoil in fear at the backs of their cages or viciously attack the cage, gnawing at the wire mesh until their gums bled as they tried to break out of their cage and attack the person standing there.
Belyaev conducted an experiment to see if puppies born to the human-aggressive foxes would become tame if they were raised by a human-friendly mother fox. In trial after trial, Belyaev found that the fearful and combative traits that had been bred into the human-aggressive pups were not at all diminished when the pups were raised by human-friendly mothers. Belyaev and his colleagues had no choice but to conclude that tameness was a genetic issue and not an environmental one. Eventually, the research team was actually able to distinguish the DNA of the tame foxes from that of the human-aggressive foxes.
As genetics doesn’t easily lend itself to visualization or quantification in our every day lives, it’s always going to be difficult for us to appreciate just how much it dictates the person that we are. DNA is like the wizard hiding behind the curtain in Oz: unseen but clearly the master puppeteer who’s pulling the strings on our temperament and behavior.
The impact that DNA had on human behavior was first established in the fascinating studies done on identical twins separated at birth. As identical twins come from the same egg and sperm and have the same genetic material, studying identical twins that were separated at birth presented the perfect opportunity to try to differentiate between the traits that are genetic (nature) and the traits that are environmental (nurture.) Ordinary siblings and fraternal twins wouldn’t work for this kind of study as siblings and fraternal twins only share fifty percent of their genetic material since they’re conceived from different eggs and sperm.
The insights discovered from the study of identical twins raised apart have been groundbreaking. The Minnesota Twin Family Study, an infamous research project done in 1979, was one such study. Thomas Bouchard and a team of psychologists spent twenty years studying one hundred thirty-seven sets of identical twins that had been raised apart from birth.
The most important revelation to be uncovered by the Minnesota Twin Study had to do with the discovery that
the temperament, attitude and interests of identical twins raised apart were no different from temperament, attitude and interests of identical twins raised together. What this means is that the traits that persevered in the twins, whether they were raised apart or together, were the result of their shared genetic material.
Before this study, the general consensus of the psychological community was that temperament and behavior arose from our environmental influences. The Minnesota Twin Study instantly kick-started a revolutionary new awareness that DNA had a much greater impact on our temperament and behavior than was ever previously believed.
One incredible example from the Minnesota Twin Study is so surreal and unbelievable that it deserves mention here. It involves a set of twins who were separated at four weeks old and weren’t finally re-united until they were thirty-nine! Surprisingly, both boys were named James by their adoptive parents (as if there was something intrinsically compelling about their countenance that inspired that particular name!) As children, both boys had dogs that they named “Toy.” As adults, both men were currently married to women named Betty and both had been divorced from women named Linda. Each man had christened his first-born son James and both had given their son the middle name of Alan (though one had spelled it “Allan”). Each man had previously worked as a sheriff and both men were currently employed as firemen. They both enjoyed woodworking as a hobby and they each drove light blue Chevrolets and yearly vacationed at Pas Grille beach in Florida. They both smoked Salem cigarettes and drank Miller Lite beer, both holding the beer cans by the bottom using their pinky finger. They both compulsively bit their fingernails and suffered from migraine headaches. Both men had the habit of leaving love notes for their wives in various places around the house and both men gained ten pounds at the same time for no apparent reason.
The Minnesota Twin Study gave us our first powerful glimpse into the incredible world of genetics. The full extent in which genetics impacts our temperament and behavior is something that won’t be known for many, many years since the study of genetics is in its infancy. Though we’ve come a long way in our understanding of DNA, if all there is to know about genetics is Mount Everest, then we’ve only reached the first base camp: there’s an entire mountain’s worth of knowledge yet to explore!
This book is devoted to the importance of genetics, especially as regards our temperament. Once we understand just how much DNA rules our lives, we’ll find that it’s much easier to accept our own and other people’s behavior in the very same way that we accept the behavior of our dogs is dictated by their breed.
In the next chapter, we’re going to explore in detail the fascinating topic of temperament. We’ll discover that our DNA dictates our temperament and behavior as much as it dictates the color of our eyes and hair. Woof!