For the Love of a Dog (17 page)

Keep all this in mind if you’re buying a puppy-mill puppy because you fell in love with his sad, sweet eyes, or if you’re rescuing an adult dog raised in compromised conditions. Far be it from me to tell you to walk away from some poor dog who’s had a bad start—just ask Bo Peep how well I did at making a cool, dispassionate decision after taking one look at her crippled little body. But for the sake of both you and the dog, I want you to be realistic about what to expect. Some dogs, probably because
of superior genetics, can experience negligent, even abusive conditions, and still mature into emotional health. My Luke lived an isolated and unhealthy life between the ages of two months and eleven months, but because of his first weeks in a healthy, enriched environment and an amazing set of genes, he developed into one of dogdom’s great ambassadors.

Luke adored people and dogs, and he tolerated just about anything from just about anybody. I hope you’re as lucky as I was; I can’t imagine ever again having a dog as noble as Luke. But for every dog like him, there are a hundred whose deprivation early in life results in their inability to tolerate change or stimulation of any kind. Perhaps the Australian Shepherd you rescued, the one who lived in a cage for three years pumping out puppies in a puppy mill, may never be able to compete in agility despite her phenomenal physical skills. The retired racing Greyhound you adopted might not be able to tolerate the cheerful pandemonium that goes along with four teenagers in the house. The show prospect who never left her spotless kennel until eight months of age may never be comfortable around unfamiliar men. I’m not trying to talk you out of adopting a dog who had a tough beginning in life. The world is full of dear, damaged dogs who desperately need homes. Lots of wonderful people rescue them, and those people deserve our heartfelt appreciation. If you want to join their ranks, my hat’s off to you. In spite of the importance of early development, patience and hard work can go a long way to rehabilitate dogs damaged in their youth by unsuitable environments.

Just remember that this might not be the dog who wins you that obedience competition title you’ve always wanted. Victory with a dog who’s been severely damaged by a neglectful upbringing is more likely to include finally enabling her to tolerate a house sitter when you go on vacation (rather than destroy the house or leap through the second-story window), or teaching him to walk politely down the street without leaping and snarling toward every dog he sees. Don’t feel like a failure if you can’t make a social butterfly out of the dog you rescued from a nightmarish beginning. Giving him a kind, loving home and helping him to relax enough to nap in your lap are achievements in their own right. If you can manage them, you deserve much more than a blue ribbon and a silver chalice. However, if what you absolutely have
to have right now is a stable, easygoing dog who is adaptable to a changing environment, then you’d be wise to take this chapter to heart.
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Funny I’d use that phrase, “to heart,” when writing a chapter about the brain. I doubt that the decision I made about bringing home Bo Peep was actually made in the chambers of my heart. That organ was too busy thumping away, pumping blood to the energy-hungry nerve cells inside my head. We may speak of the heart as the center of our emotions, but as we all know, emotions actually come from our brains. The brain is a kind of emotional master of ceremonies, and this is, yet again, something that we share with our dogs. Learning a bit more about how the brain works, once it is fully formed, can go a long way toward helping us understand the emotional connection between us and our dogs.

The complexity of a fully formed brain, whether it’s yours or your dog’s, is absolutely astounding. A piece of your brain no bigger than a grain of sand has 100,000 nerve cells in it. Each microscopically small nerve cell, called a neuron, is still big enough to connect with thousands of other neurons. (It is these vital connections that are lacking in animals raised in sterile environments.) In total, your brain contains over 100 billion neurons, with 10 trillion connections between them. Heaven only knows how many of those connections are being used as you read this, but if you tried counting them one by one, you couldn’t finish in a lifetime.

Speaking of lifetimes, it would take forty-four thousand of them to count the sum total of
all
the connections between nerve cells in your brain. I don’t know about you, but facts like this evoke the same feeling in me that I get when I look up at the stars at night. I don’t care how many neurons we have, there aren’t enough to handle the concept of 10 trillion, much less that of infinity.

All these connections allow the brain to act as a filter, a switchboard,
a maintenance crew, and a board of directors. It weighs a total of three pounds in a 150-pound human, and about a fifth of a pound in the head of a Beagle. The brains of humans are huge compared to our body weight. The brain of a gorilla weighs only a third as much as ours, while a gorillas body weight is two to three times that of a human. Even a whale’s brain weighs only about four times as much as ours, when a whale’s body weight can be more than four hundred times greater than ours. No doubt about it, our brains are phenomenally large. Even if your dog is a genius, his brain is proportionately tiny compared to yours. No matter how smart your dog is and how much you love him, the fact of the matter is that your brain, in some important ways, is different from his. These differences are important, and we’ll talk more about them in a later chapter.

However, for all the differences between the size and function of our brains and the brains of our dogs, the similarities between them are amazing. Canine and human brains are made up of the same basic structures and they function the same way. The brains of all animals are made up of neurons, their tangle of connections, and a supportive scaffolding that provides structure and nourishment to the hardworking nerve cells. It turns out that it takes a lot of energy to keep all this activity running smoothly. It also turns out that the energy required to power your brain has an important effect on emotions.

Brains are energy guzzlers. In humans, they use 25 percent of the body’s oxygen and many of the body’s available calories. This hunger for energy means that blood flow is increased to areas of the brain that are actively working, as the blood brings fuel to the busy nerve cells. Thanks to new technologies like PET scans and fMRIs, we can track changes in blood flow, observe which neurons are active or passive, and thus know which parts of the brain are engaged when you’re petting your dog, listening to music, or watching a monster in a scary movie.
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That ability has radically changed our understanding of how the brain works. Much of our new knowledge about brain function is based upon the brain’s hunger for fuel and upon our ability to observe how energy is distributed while the brain is working (which, of course, is all the time).

The energy requirements of the brain are impressive. Our brains are indeed remarkable things, but they come at a high price. Think of them as the SUVs of organs, requiring disproportionately large amounts of energy compared with the rest of the body. No wonder we get so tired when we’re learning something new. How many times have you said you weren’t “physically tired,” you were “mentally tired”? It turns out that both states are physical in nature, part and parcel of the same basic process, you just feel them in different ways. It all gets down to “Energy in, energy out”—if too much goes out because your brain is working harder than usual, you feel it in your mind rather than your muscles.
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This is vital information for those of us who need an arctic outfitter to walk our dogs in January, or who have high-energy dogs of herding breeds and yet no flock of sheep in the garage. You can spend a half an hour teaching your dog some new tricks and get almost the same effect as if you’ve walked her for an hour. Keep it lighthearted and fun, use lots of positive reinforcement, and try hard to motivate your dog to want to learn. Of course, your dog is still going to need some physical exercise, but the combination of the two will go a long way to keep Maggie from munching on your couch or bouncing off your walls.

The downside of all this is that your dog can get mentally overtired, just like you can. Remember those frowning dogs we talked about in the last chapter, the ones whose faces signaled that they were running out of patience? I’ve seen hundreds of them, I’m afraid, dogs who had been doing wonderfully at the family picnic or during the New Year’s Eve party, but ruined the occasion by snapping at someone as the festivities were winding down. Many of these dogs were good dogs who, I believe, didn’t want to hurt anyone. They were simply exhausted, not just from
running or swimming all day long, but from the constant stimulation of being in a crowd of people. The dogs simply ran out of steam, and ultimately out of patience. Keep in mind that your dog needs you to protect him from mental as well as physical exhaustion. It’s a wise and loving owner who gives his dog a break long before she’s had enough.

All mammals, including you and your dog, use a combination of electricity and chemistry to move signals around inside our heads. A neuron that’s been “turned on” by something—from the touch of a nose to the sound of a bark—sends an electrical signal down its connections toward other neurons. In a human, the sum total of all this mental electricity is the equivalent of a ten-watt light bulb, a pretty impressive amount if you think about it.

Electricity isn’t enough to move information through the brain, because the threadlike extensions of neurons that stretch toward other neurons don’t physically connect. The gap between them is tiny, but electricity can’t jump across it. Chemicals called neurotransmitters bridge the gap, moving through fluid from the end of one threadlike connection to another. As soon as the connecting fiber receives these chemicals, electricity takes over again. It moves the signal through the next neuron and down another connecting fiber, until it comes to another gap, where the neurotransmitters take over again. This alternation of electricity and chemistry is happening right now, billions of times, at blinding speeds, in both you and your dog. No wonder we can get tired just sitting at a desk all day.

The chemical messengers that travel between neurons do far more than move signals from one cell to another. They are vital to how you and your dog feel at any given time. In the last thirty years, we’ve learned that neurotransmitters, such as serotonin and dopamine, have a profound affect on our emotions. Serotonin acts to dampen feelings of fearful arousal, and is associated with the experience of pleasure and contentment. That’s why so many depressed people benefit from mood-elevating drugs that increase the amount of serotonin available to the cells in their brains. Dopamine plays an equally important role
in feelings of pleasure (and addictions). The roles these chemicals play are complex; many of them have complicated job descriptions that we haven’t begun to sort out. Dopamine, for example, is vital to your brain’s ability to focus your attention—its release causes all your brain cells to cease firing for a microsecond, and then prepares them to fire in anticipation of an important event—but it’s also a key player in feelings of reward and satisfaction.

Neurotransmitters aren’t the only chemicals in your brain that affect mood. Hormones move through the bloodstream rather than between the cells of our brains, and have a profound effect on emotion. For example, the release of the hormone oxytocin causes the uterine contractions that are vital during the birth of all mammals, but it also affects our emotional state. As we’ll see in more detail in a later chapter, if you feel all warm and soft when you pick up a puppy, it’s because your body is being flooded with a wave of oxytocin. Surges of oxytocin lead to strong feelings of love and attachment, and are so important that mothers who don’t produce them can have problems bonding with their children.
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We’ll talk more about neurotransmitters and hormones in the chapters about fear, anger, happiness, and love, but for now what’s important is that these same chemicals play an equivalent role in the brain and the body of your dog. The evidence is overwhelming that other mammals, including our dogs, produce the same chemicals in their brains, and that these chemicals have much the same effect on them as they do on us. Indeed, our knowledge about the function of these substances comes largely from work done on other mammals. Healthy levels of serotonin have been found to inhibit aggression and encourage friendly social behavior in many species of animals, including humans, nonhuman primates, and rats. Sheep who have been given a drug that blocks the action of oxytocin reject their own lambs as soon as they are born. Dopamine plays an important role in addictive behavior in rats and monkeys, just as it does in humans.

Keep this in mind when someone argues to you that dogs don’t have emotions. Not only do dogs show the same changes in facial expression
and posture that humans do, but their internal brain chemistry appears to parallel ours as well. The chemistry that controls our emotions is found in similar contexts and similar areas of the brain in dogs. Oxytocin appears to have the same effect on dogs as it does on us—not only stimulating uterine contractions but also facilitating bonding and nurturance. There is a growing body of research that correlates certain types of aggression in dogs with low levels of serotonin; this evidence replicates some of the findings in human neuropsychology Hyperanxious dogs appear to suffer the same chemical imbalances that extremely anxious people have. Of course, I’m not arguing that dogs and humans have exactly the same emotions, or that they experience them in exactly the same way. But, as our ability to understand the biology of emotion increases, it is becoming increasingly clear that, in many ways, dogs may be more like us than they are different from us.