What the Dog Knows (5 page)

At least those polytheistic religions allowed dogs to play a variety of roles—they might devour bodies, but they were guardians and guides, too. Homer may have opened the
Iliad
with ravening dogs, but in the
Odyssey
, he used his hero's dying dog as a symbol of faithfulness: Argos was the only being to recognize Odysseus when he returned from his
travels after a twenty-year absence. Those diverse dog roles didn't carry over to monotheism. Historian Sophia Menache of the University of Haifa posits that Jewish, Christian, and Muslim religions were threatened by dogs and the “warm ties” people had to them. Dogs had a central role in agrarian life; they reminded monotheists of the ever-present competition of animal-worshipping cults. So when we ask questions about organized religion and we ask, “Yes, but was it good for the dogs?” the answer is no. The New Testament's thirty-two mentions of dogs are mostly negative. Though the antipathies and insecurities of the three religions have softened and shifted somewhat in intervening centuries, dogs get short shrift in many Muslim countries, and some Christians want dominion over the natural world.

Even today, in a secular Western world, we remain oddly fascinated by the role that dogs play in death. Scamp, a schnauzer at an Ohio nursing home, got wide news coverage in 2007 for his habit of barking and pacing near patients' rooms when they were about to die. He had “eerily” raised the alarm for forty deaths in three years, the director of nursing told
Inside Edition
. Far from shunning him, the patients adored him. “It's not like he's a grim reaper,” director of nursing Adeline Baker told the reporter. “It's kind of comforting to know that maybe at the end of our lives, if we don't have family members, there will be somebody there to be with us.”

Perhaps Scamp was a comfort because he wasn't large and black but small and gray with quizzical eyebrows. The darker side of our superstitions has also survived: More big black dogs are reportedly euthanized in U.S. shelters than any other size or shade.

In modern times, we have updated and sanitized the Homeric language of “devouring dogs.” Forensic scientists now call it “canine predation.” Despite having a name for the phenomenon, we tend to keep an uneasy distance. Yet, a few years ago, children streamed into our local science museum for one of its most popular shows ever, on bugs and death. Shows like
CSI
and
Bones
have made us surprisingly comfortable with maggots, and what they tell us about the stages of
death, and have contributed to the popularity of an entire discipline: forensic entomology. Scientists know a fair amount about bear activity; they know less about dog activity. Yet the handful of available studies show that dogs and their coyote cousins account for much of the scavenging on human remains.

The media appear to know a lot about dogs finding the dead. The problem is that stories are scattered everywhere, hundreds and thousands that all have the same innocuous story line: A person walking a dog finds a body. I am convinced that an analysis would show that untrained dogs out for walks or roaming neighborhoods find more bodies than trained dogs do. It's a simple question of acknowledging the millions of dog noses out there working unpaid overtime.

Depending on your perspective, it's either good or bad to let your dog roam off-lead, but let's face it: Dogs on leads don't find bodies nearly as often. Generally, finding a body is a good thing, although the dogs' owners and walkers are never thrilled when it happens.

Ollie, a golden retriever, was in Hollywood Hills on an unleashed walk in January 2012. A professional dog walker and her mother had eight other dogs with them. Ollie dashed into the underbrush and started playing enthusiastically with a plastic bag: “He was digging, digging, digging, barking,” the dog walker, Lauren Kornberg, told the local radio station. Ollie shredded the bag and came away with something big and round in his mouth. He dropped it, and it rolled into a ravine. Kornberg admitted that it was her mother, “a responsible adult,” who went to investigate—and found the head that Ollie had dropped.

A four-year-old black Labrador named Fish brought a decaying human arm into the front yard of his Mission, Texas, home in August 2011. Police were able to get the hand and arm bone before they disappeared down Fish's throat. The dog's adult owner was traumatized. Not so his eight-year-old daughter, who chatted with the television reporter. Their dog, she said, likes to visit the neighbors' chicken coop as well: “Fish gets everything. He brought eggs on Easter.”

I understand her father's repulsion. I wouldn't accept Fish's gift of eggs.

When dogs become, in Paul Shepard's term, “the spoiler of human graves,” it's a reminder of how we tend to deal with human bodies. We Westerners tuck them away fairly quickly. Dogs like Fish remind us of the disorder and chaos inherent when there's an arm or hand lying around where a dog can find it. We prefer hands either made into sterile ash or nicely preserved with formaldehyde and gently crossed over the body in a coffin. On the flip side, turnabout should be fair play. Both historically and in current practice across the world, people eat dogs without much compunction. There's good evidence that dogs were and are raised for meat; they were the first agricultural animal in a number of societies, and they remain so in some today.

None of my early research on cadaver dogs grossed me out. I realized there was a difference between reading about it and coming face-to-face with it, but abstractly, the idea of cadaver-dog work didn't offend my sensibilities. It made me happy. Perhaps my childhood in the woods and fields, growing up with fishing and hunting and gutting and plucking and skinning, was a factor in my sanguinity. Or the fact that I had taken care of my paralyzed mother and worked in nursing homes for years. Perhaps it was because my father was a biologist who taught me to look at dead organisms with a disinterested but not uninterested gaze.

Cadaver-dog work seemed straightforward to me. As one medical examiner and early cadaver-dog trainer, Edward David, noted with great cheer, “love of the putrid” is inherent in canines. So why not take that love and channel it toward something more socially useful than rolling in dead squirrel?

Why not take that love and see whether it might be used not to increase the chaos but to restore, even if only slightly, a sense of order?

There are seventy-five perfumes, which it is very necessary that a criminal expert should be able to distinguish from each other, and cases have more than once within my own experience depended upon their prompt recognition.

—Sherlock Holmes,
The Hound of the Baskervilles
, 1902

These days, when I watch a good dog work scent, I can see him trace its passage in the air until he's drawn a clear picture with his nose. An experienced dog can illustrate the difference between scent that has
lifted in the heat of the day, settled down in the ridges of rough grass, or been pulled hard toward the rushing water of a creek.

I work scent also, though I don't run as fast or as hard. I can recognize urine in the muggy concrete stairwell of a parking garage, mildew liberated from under sheaves of rotted leaves, and the fishy musk of a German shepherd after a swim in the Eno River in August.

I knew, even before I started researching dogs' noses in a sustained manner, that they were much better than humans'. Solo's was much better than mine. David could use a pair of scissors on a package of vacuum-sealed meat in the kitchen, and the silent exhalation of bloody air would wake Solo and bring him running from across the room. Conversely, it seemed lazy to concede that dogs are the masters of the domain of olfaction before I'd done any scientific fact-checking. Sure, Solo has a bigger nose than I do, but size isn't everything.

So what's the truth about dogs' sense of smell? I don't want to keep the reader in suspense: The truth is, we don't know that much about it. As I began researching, I noticed wildly fluctuating figures in both the sentimental and scientific dog literature: The dog's nose was either ten times or a hundred times or a thousand times or tens of thousands of times better than the human nose. Those figures raised doubts. If scientists, or people who play them on YouTube, or your basic dog lover had stuck with one false figure—say, that dogs' noses are a thousand times better than ours—or if they had stated the figures with less certainty and more modesty, I might not have become suspicious. Given the variation, I wondered, how much better are dogs' noses, really? And if they are better, what are they better
for
, exactly? Sniffing dog pee?

In tracking rumors, as with tracking most things, it's good to start at their genesis. There's a growing body of scientific evidence suggesting that not only have the nose and its receptors been important to the survival of creatures for at least hundreds of millions of years; they may also have been a key evolutionary force driving the growing intelligence of mammals.

In 2011, Texas paleontologists published their analysis of the skulls
of pre-mammals living 190 million years ago. Their research shows that one of our pre-mammalian ancestors, the
Hadrocodium wui
—a shrewish beast with a skull smaller than a paper clip—didn't have the option of rejecting smells. It tremulously ventured forth to sniff for grubs and insects, probably at night so the diurnal dinosaurs didn't accidentally squash it. Its fur was important, its twitchy ears important, its vision important. But, the paleontologists argued in
Science
, it was the critter's olfaction system that was the most impressive thing in that bitty skull: “[It] differed from even its closest extinct relatives specifically in its degree of high-resolution olfaction, as it exploited a world of information dominated to an unprecedented degree by odors and scents.” They theorized that these skulls showed the olfactory system played a major role in helping the mammalian brain evolve, apparently to the point that we humans—the most advanced of mammals—could turn our collective nose up at thinking too much about smells.

We should feel grateful to the tiny
Hadrocodium wui
, fossilized and preserved in China, for helping us understand the importance of a sense of smell. Yet there's still much about this sense that scientists don't know. It was only recently that researchers started to decode how our olfactory system actually works. Thanks to Linda Buck and Richard Axel, who won the Nobel Prize in 2004, we've learned that when a volatile aroma latches on to an odorant receptor, it fires an olfactory neuron. Bam. That is not the only theory out there, but it's the reigning one. You would think that researchers would be further along in understanding this particular sense, but amid the general devaluing of the sense of smell in the Western world, the chemical complexity of odors, and the complexity of the neural circuitry that underlies even the act of sniffing, they have a ways to go.

As for comparing one nose with another? Neurobiologists aren't that interested in setting up olfaction competitions between species. They don't care which species' nose is “the best.” What does that mean, in any case? This kind of speculation is better left to Animal Planet's
Creature Countdowns
, featuring the “Top 10 Animal Troublemakers”
and “Top 10 Animal Skills.” The bloodhound made number nine on that last list, with a sense of smell so fine, according to the producers, that it is “up to a million times more sensitive than that of humans.” I am not making this up. Animal Planet is.

Some species' noses do rise above the rest, literally and figuratively. I bet if we could train bears to track, their noses would confer real bragging rights. Biologists believe that grizzly bears generally have a much better sense of smell than any dog. Bears' noses get less press than dogs' for all the obvious reasons. If you ever get the chance to stare at a grizzly's nose close up, you can see what a stunning instrument it is—tilted up at the end, with huge flaring nostrils. If you are at exactly the right angle, you can see through that nostril space to the blue sky beyond. The grizzly bear can manipulate her nose like a flautist can flex her fingers. If you could peer inside her
horribilis
skull at the nasal cavity, you would see delicate structures that look like two huge morel mushrooms or rounded honeycombs planted side by side. Their job is to process scent. How well? Pretty darn well. For miles, it's estimated.

But maybe not for miles and miles and miles. Nonetheless, Animal Planet, some books, and a number of bear websites use the following phrase: “Some scientists say bears can smell carrion from up to 18 miles (29 kilometers) away.” It's rather odd, I thought, that “some scientists” would all agree on such a specific bear mileage. The figure's genesis, I discovered, was one 1976 bear-conference paper noting that one radio-tracked bear traveled twenty-nine kilometers with some speed and ended up at a carcass. The ecologist, Frank Craighead, stipulated, “It was not determined just when and how the carcass was detected.”