Read Inside of a Dog: What Dogs See, Smell, and Know Online

Authors: Alexandra Horowitz

Tags: #General, #Dogs, #Science, #Life Sciences, #Psychology, #Cognitive Psychology, #Dogs - Psychology, #Pets, #Zoology, #Breeds

Inside of a Dog: What Dogs See, Smell, and Know (5 page)

BOOK: Inside of a Dog: What Dogs See, Smell, and Know
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These rats had learned optimism or pessimism about the world. To watch the rats in the predictable environments jump with alacrity at every new sound is to see optimism in action. Small changes in the environment were enough to prompt a large change in outlook. Rat lab workers' intuitions about the mood of their charges may be spot-on.
We can subject our intuitions about dogs to the same kind of analysis. For any anthropomorphism we use to describe our dogs, we can ask two questions: One, is there a natural behavior this action might have evolved from? And two, what would that anthropomorphic claim amount to if we deconstructed it?
DOG KISSES
Licks are Pump's way of making contact, her hand outstretched for me. She greets me home with licks at my face as I bend to pet her; I get waking licks on my hand as I nap in a chair; she licks my legs thoroughly clean of salt after a run; sitting beside me, she pins my hand with her front leg and pushes open my fist to lick the soft warm flesh of my palm. I adore her licks.

I frequently hear dog owners verify their dogs' love of them through the kisses delivered upon them when they return home. These "kisses" are licks: slobbery licks to the face; focused, exhaustive licking of the hand; solemn tongue-polishing of a limb. I confess that I treat Pump's licks as a sign of affection. "Affection" and "love" are not just the recent constructs of a society that treats pets as little people, to be shod in shoes in bad weather, dressed up for Halloween, and indulged with spa days. Before there was any such thing as a doggy day care, Charles Darwin (who I feel confident never dressed up his pup as a witch or goblin) wrote of receiving lick-kisses from his dogs. He was certain of their meaning: dogs have, he wrote, a "striking way of exhibiting their affection, namely, by licking the hands or faces of their masters." Was Darwin right? The kisses feel affectionate
to me,
but are they gestures of affection
to the dog?

First, the bad news: researchers of wild canids—wolves, coyotes, foxes, and other wild dogs—report that puppies lick the face and muzzle of their mother when she returns from a hunt to her den—in order to get her to regurgitate for them. Licking around the mouth seems to be the cue that stimulates her to vomit up some nicely partially digested meat. How disappointed Pump must be that not a single time have I regurgitated half-eaten rabbit flesh for her.
Furthermore, our mouths taste great to dogs. Like wolves and humans, dogs have taste receptors for salty, sweet, bitter, sour, and even umami, the earthy, mushroomy-seaweedy flavor captured in the flavor-heightening monosodium glutamate. Their perception of sweetness is processed slightly differently than ours, in that salt enhances the experience of sweet tastes. The sweet receptors are particularly abundant in dogs, although some sweeteners—sucrose and fructose—activate the receptors more than others, such as glucose. This could be adaptive in an omnivore like the dog, for whom it pays to distinguish between ripe and non-ripe plants and fruit. Interestingly, even pure salt doesn't kick-start the so-called salt receptors on the tongue and the roof of the mouth in dogs the way it does in humans. (There's some disagreement whether dogs have salt-specific receptors at all.) But it didn't take long reflecting on her behavior for me to realize that Pump's licks to my face often correlated with my face having just overseen the ingestion of a good amount of food.
Now the good news: as a result of this functional use of mouth licking—"kisses" to you and me—the behavior has become a ritualized greeting. In other words, it no longer serves only the function of asking for food; now it is used to say hello. Dogs and wolves muzzle-lick simply to welcome another dog back home, and to get an olfactory report of where the homecomer has been or what he has done. Mothers not only clean their pups by licking, they often give a few darting licks when reuniting after even a brief time apart. A younger or timid dog may lick the muzzle, or muzzle vicinity, of a bigger, threatening dog to appease him. Familiar dogs may exchange licks when meeting at their ends of their respective leashes on the street. It may serve as a way to confirm, through smell, that this dog storming toward them is who they think he is. Since these "greeting licks" are often accompanied by wagging tails, mouths opened playfully, and general excitement, it is not a stretch to say that the licks are a way to express happiness that you have returned.
DOGOLOGIST

I still talk about Pump's looking "knowingly," or feeling
content
or
capricious.
These are words that capture something to me. But I have no illusion that they map to her experience. And I still adore her licks; but I also adore knowing what they mean to her rather than just what they mean to me.

By imagining the umwelt of dogs, we'll be able to deconstruct other anthropomorphisms—of our dog's guilt at chewing a shoe; of a pup's revenge wrought on your new Hermès scarf—and reconstruct them with the dog's understanding in mind. Trying to understand a dog's perspective is like being an anthropologist in a foreign land—one peopled entirely by dogs. A perfect translation of every wag and woof may elude us, but simply looking closely will reveal a surprising amount. So let's look closely at what the natives do.
In the following chapters we will consider the many dimensions contributing to a dog's umwelt. The first dimension is historical: how dogs came from wolves, and how they are and are not wolflike. The choices we've made in breeding dogs led to some intentional designs and some unintended consequences. The next dimension comes from anatomy: the dog's sensory capacity. We need to appreciate what the dog smells, sees, and hears … and if there are other means by which to sense the world. We must imagine the view from two feet off the ground, and from behind such a snout. Finally, the body of the dog leads us to the brain of the dog. We'll look at the dog's cognitive abilities, the knowledge of which can help us to translate their behavior. Together, these dimensions combine to provide answers to the questions of what dogs think, know, and understand. Ultimately they will serve as scientific building blocks for an informed imaginative leap inside of a dog: halfway to being honorary dogs ourselves.
Belonging to the House
She's waiting at the threshold of the kitchen, just beyond underfoot. Somehow Pump knows precisely where "out of the kitchen" is. Here she sprawls, and when I bring food to the table, she ducks in to retrieve the kitchen fallings. At the table, she gets a little of everything—and she'll at least entertain even the most unlikely offering, if only to loll it around in her mouth before unceremoniously depositing it on the ground. She does not like raisins. Nor tomatoes. She'll suffer a grape, if she manages to split it into juicy halves with her side teeth—then deliberating, as though managing a very big or tough object, and masticating it. All carrot ends are for her. She takes the stems of broccoli and asparagus and holds them gently, gazing at me for a moment as if determining if anything else is coming before walking to the rug to settle down for a gnaw.
Dog training books often insist that "a dog is an animal": this is true but is not the whole truth. The dog is an animal
domesticated,
a word that grew from a root form meaning "belonging to the house." Dogs are animals who belong around houses. Domestication is a variation of the process of evolution, where the selector has been not just natural forces but human ones, eventually intent on bringing dogs inside their homes.
To understand what the dog is about we have to understand from where he came. As a member of the
Canidae
family—all of whose members are called
canids
—the domestic dog is distantly related to coyotes and jackals, dingoes and dholes, foxes and wild dogs.*
But he arose from just one ancient
Canidae
line, animals most likely resembling the contemporary gray wolf. When I see Pumpernickel delicately spit out a raisin, though, I am not reminded of the stark images of wolves in Wyoming downing a moose and yanking it apart.† The existence of an animal who will patiently wait at the kitchen door, and then ponderously consider a carrot stick, seems at first glance irreconcilable with that of an animal whose primary allegiance is to himself, whose affiliations are fraught with tension and maintained by force.
Carrot-considerers arose out of moose killers through the second source: us. Where nature blindly, uncaringly "selects" traits that lead to the survival of their bearers, ancestral humans have also selected traits—physical features and behaviors—that have led not just to the survival, but to the omnipresence of the modern dog,
Canis
familiaris,
among us. The animal's appearance, behavior, preferences; his interest in us and attention to our attention: these are largely the result of domestication. Present-day dog is a well-designed creature. Only much of this design was utterly unintentional.

HOW TO MAKE A DOG: STEP-BY-STEP INSTRUCTIONS

So you want to make a dog? There are just a few ingredients. You'll need wolves, humans, a little interaction, mutual tolerance. Mix thoroughly and wait, oh, a few thousand years.
Or, if you're the Russian geneticist Dmitry Belyaev, you simply find a group of captive foxes and start selectively breeding them. In 1959, Belyaev began a project that has greatly informed our best guesses as to what we believe the earliest steps of domestication were. Instead of observing dogs and extrapolating backward, he examined another social canid species and propagated them forward. The silver fox in Siberia in the mid-twentieth century was a small, wild animal that had become popular with the fur trade. Kept in pens, bred for their choice fur coats, particularly long and soft, the fox was not tamed but was captive. What Belyaev made of them, with a much reduced recipe, were not "dogs," but were surprisingly close to dogs.
Though
Vulpes vulpes,
the silver fox, is distantly related to wolves and dogs, it had never before been domesticated. Despite their evolutionary relatedness, no canids are fully domesticated other than the dog: domestication doesn't happen spontaneously. What Belyaev showed was that it can happen quickly. Beginning with 130 foxes, he selectively chose and bred those that were the most "tame," as he described it. What he really chose were those foxes that were the least fearful of or aggressive toward people. The foxes were caged, so aggression was minimal. Belyaev approached each cage and invited the fox to eat some food out of his hand.
Some bit at him; some hid. Some took the food, reluctantly. Others took the food and also let themselves be touched and patted without fleeing or snarling. Still others accepted the food and even wagged and whimpered at the experimenter, inviting rather than discouraging interaction. These were the foxes Belyaev selected. By some normal variation in their genetic code, these animals were naturally calmer around people, even interested in people. None of them had been trained; all had the same, minimal exposure to human caretakers, who fed them and cleaned their bedding for their short lives.
These "tame" foxes were allowed to mate, and their young were tested the same way. The tamest of those were mated, when they were old enough; and their young; and their young. Belyaev continued the work until his death, and the program has continued since. After forty years, three-quarters of the population of foxes were of a class the researchers called "domesticated elite": not just accepting contact with people, but drawn to it, "whimpering to attract attention and sniffing and licking"… as dogs do. He had created a domesticated fox.
Later genomic mapping has revealed that forty genes now differ between Belyaev's tame foxes and the wild silver fox. Incredibly, by selecting for one behavioral trait, the genome of the animal was changed in a half century. And with that genetic change came a number of surprisingly familiar physical changes: some of the later-generation foxes have multicolored, piebald coats, recognizable in dog mutts everywhere. They have floppy ears and tails that curl up and over their backs. Their heads are wider and their snouts are shorter. They are improbably cute.
BOOK: Inside of a Dog: What Dogs See, Smell, and Know
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