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 that the dog’s owner simply isn’t raising the dog correctly (just as when a child misbehaves, people always believe that it’s the parents who are at fault).
I absolutely agree that behavior (both dog and human) will always be impacted by the way an individual is raised and the treatment received, especially if there’s any mistreatment or abuse. But I don’t agree that environmental factors have the greatest influence on behavior. In my opinion, that honor belongs to DNA. Since it’s widely underestimated just how pivotal genetics is when it comes to temperament and behavior, this book is a humble attempt at refuting that misconception.
Whenever we examine the exterior of something, it’s often quite difficult to appreciate the hidden, inner workings going 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 since those are what we see. What we can’t see and, as a consequence, what we don’t 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, along with all the other organ systems that diligently perform their duties completely hidden from observation. Though these individual aspects of ourselves may be hidden from view, they’re crucial to 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 very same way, it’s extremely easy to zero in primarily on environmental factors whenever we take on the task of trying 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 whenever we attempt to understand what factors influence behavior. Our personal history will always be what’s foremost in our thoughts simply because that’s what we know. It wouldn’t occur to us that something that we can’t even see or experience has the greatest influence on our personality and behavior.
That most potent of invisible forces is DNA. Our DNA is so incredibly intangible that we rarely, if ever, think of it. It’s even more inaccessible than our hidden 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 humans if we take a moment to examine dogs and the genetic reasons they bite. But before I begin, I’d like to make two things extremely clear. First of all, though I’ll be making numerous generalized statements concerning the different traits of different breeds, it’s not my intention to ever malign any particular breed. These generalities are based on my thirty-plus years of experience as a veterinarian and unfortunately, not all of those generalities will be complimentary. I don’t have a personal vendetta against one breed or another, it’s simply that I’m obligated 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 incredible influence of environmental factors. Genetics and environment are both important but the extent to which they each influence behavior has yet-to-be completely illuminated. As this is a book about genetics, I hope to demonstrate that genetics is so pivotal to who we are that it serves as a template or a sort of destiny for our individuality. Being able to accept that fact is what is going to bring us peace. Now, with those two points hopefully clarified, let’s look at the genetic causes of biting in dogs.
One day, while I was at work at my veterinary practice in southern California, two police officers banged through the front door carrying a severely injured Labrador. The dog’s owner, for some reason, had gone completely berserk and had repeatedly beaten the dog with a baseball bat. It’s amazing that the poor dog wasn’t killed though he did sustain a broken leg and multiple other injuries. It was one of the saddest things that I’ve ever seen. The dog was now so completely terrified of people (and justifiably so!) that he’d cower, tremble and even urinate on himself whenever someone tried to touch him. Yet, in spite of all the abuse he’d experienced and all the procedures he’d had to endure as part of his recovery, he never once tried to bite. In fact, it quickly became quite clear that he actually adored being petted. Once he got past his initial trepidation as to whether someone was friend or foe, he seemed to melt, getting all doe-eyed and even thumping his tail in gratitude as someone gently stroked him. He simply had to get past the hurdle of that first touch. There’s no doubt in my mind that if that Lab had been some other type of breed, one more sensitive, fearful or aggressive, there definitely would have been some growling and snapping going on.
Dogs bite for a variety of reasons and most of those reasons originate with the dogs’ breeding or genetics. For example, dogs that are overly fearful ultimately use biting as a way to protect themselves. Fear-biters always anticipate the worst and strongly adhere to the Vince Lombardi adage that the best defense is a good offense. These dogs are convinced that they had better get you before you get them. Fortunately, fear-biters only really bite when their space is invaded or if someone messes with them when they don’t want to be messed with.
Other dogs born with an incredibly powerful inclination to bite are those who are descended from breeds where aggression is a highly valued commodity. Biting, for these dogs, is a part of their job. It’s simply what they were bred to do. Their motto is bite first, 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 consequence, they’re 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 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 but it’s the ultimate in tough love as it’s primarily how they control and manipulate the herd.
Terriers are a class of dog that were specifically bred 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 them 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 such 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: if they do decide to bite, they often refuse to let go. Sadly, there have always been unscrupulous individuals who secretly breed aggressive dogs in an attempt to produce a dog that can be victorious in illegal “to the death” dog fights.
Those are the primary reasons that most dogs choose to bite. Now, let’s take a look at how DNA impacts the tameness and domestication of animals. I’m fascinated by and excited to share the incredible conclusions of a half-century research project conducted in southern Siberia by a biologist named Dimitry Belyaev. The results of the study, titled “Designing The Perfect Pet, were published in the March 2011 issue of National Geographic.
Belyaev started his experiment with one hundred and thirty wild foxes that he procured from various fox farms in Siberia. The objective of the experiment was to see just how long it would take to strategically breed wild foxes until they became tame and domesticated. With each successive litter, Belyaev would carefully select the pups that were the least fearful of humans and then he would breed those foxes to one another. After only nine generations, Belyaev managed to produce a group of foxes that were so thrilled by the presence of humans that they’d whimper and whine as they wildly wiggled their bodies and wagged their tails.
Belyaev then wanted to determine the impact of environment had 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, seemingly obsessed with breaking out of the cage so that they could maul the person standing there.
Belyaev constructed an experiment where he might be able to determine whether puppies born to these human-aggressive foxes might be tamed if they were raised by human-friendly foxes. In repeated trials, Belyaev discovered that the fearful and combative traits that’d been bred into the human-aggressive pups were not diminished in the least when the pups were raised by human-friendly mothers. Belyaev and his colleagues were forced to conclude that tameness was a genetic issue and not an environmental one. The research team was actually able to eventually distinguish the DNA of the tame foxes from that of the human-aggressive foxes.
It’ll always going to be difficult for humans to appreciate the incredible influence that genetics has on our lives because genetics doesn’t easily lend itself to visualization or quantification. DNA is like the wizard that’s hiding behind the curtain: unseen yet clearly the master puppeteer who’s pulling the strings of our behavior.
The incredible impact that DNA has on human behavior was established in the fascinating studies done on identical twins who were separated at birth. As identical twins originate from the same egg and sperm and, as a consequence, share the exact same genetic material, studying identical twins raised apart from birth presented the perfect opportunity to try and differentiate between those traits that are genetic (nature) and those that are environmental (nurture.) This is in contrast to ordinary siblings and fraternal twins who share only fifty percent of their genetic material because they’re conceived from separate eggs and sperm.
The insights discovered from the studies 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 separately from birth.
The most incredible revelation uncovered by the Minnesota Twin Study concerned the discovery that
the temperament, attitude and interests of identical twins raised apart were no different from those 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 direct result of their shared genetic material.
Prior to this study, there’d been a long-standing consensus that behavior was primarily the result of environmental influences. The Minnesota Twin Study kick-started a revolutionary new awareness that our genetics had a much greater impact on behavior than ever been previously believed.
One example from the Minnesota Twin Study is so surreal that it definitely deserves mention here. It involved a set of twins who were separated when they were only four weeks of age and who weren’t re-united until they were thirty-nine years old. Oddly, 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 boys, both had dogs that they’d named “Toy.” As adults, both were currently married to women named Betty and both were divorced from women named Linda. Each man had christened his first-born son James and both had given their sons the middle name Alan (though one had spelled it “Allan”). Each man had previously worked as a sheriff and both were presently employed as firemen. They both enjoyed woodworking as a hobby and they each drove light blue Chevrolets and yearly went to Pas Grille beach in Florida for family vacations. They each smoked Salem cigarettes and drank Miller Lite beer, both of them holding the beer can by the bottom using their pinky fingers. They both compulsively bit their fingernails and suffered from migraine headaches.
Both men had the habit of leaving love notes around the house for their wives and they each had mysteriously gained ten pounds at the same time for no obvious reason.
The Minnesota Twin Study offered the first powerful glimpse into the incredible influence of genetics. The full extent to which genetics impacts our behavior is still unknown as the study of genetics is only in its infancy. Though we’ve certainly come a long way in our understanding, if all there is to know about genetics is Mount Everest, then we’ve only barely reached the first base camp: there’s an entire mountain’s worth of knowledge yet to explore!
This is a book that’s devoted to the importance of genetics, especially as regards temperament. As we discover just how much DNA rules our lives, hopefully we’ll be able to accept and be at peace with our own temperament and personality (as well as that of the people whose lives we share) in the same way that we accept and appreciate the temperament and personality of our dogs.
In the next chapter, we’re going to explore in detail at the fascinating topic of temperament and see how it completely dictates our behavior from the day that we’re born. Who we are is as determined by the nine categories of temperament as are the color of our hair, eyes, and skin. Woof.