Coren likens our shedding skin cells to the
Where a dog begins on a track is naturally where the scent is weakest, because it’s been there longest. As the track progresses in the right direction, the scent should get stronger. The increasing strength of a track is something dogs rely on. “They start at the farthest point in the past and work their way up, we hope, to the present moment, where they find who they’re tracking,” says Marine Corporal Wesley Gerwin, course chief/instructor supervisor for the combat tracker course. “It’s sort of like a dog’s version of time travel.”
Dry heat and ultraviolet light can cause a track to disintegrate quickly. Moisture and lack of sun help preserve tracks. Even if someone tries to throw a dog off the scent by going through a stream or river, there’s still likely to be a track. In most cases, if the dog is not too far behind, the water will not erase the scent. In fact, breezes can waft a person’s scent to a moist riverbank, where it can remain for a long time. (If a river is flowing very quickly and is relatively shallow, though, the scent dissipates far more swiftly.)
There aren’t many combat tracking dogs in the military. The numbers are in the low dozens, but security concerns preclude a more precise count. CTD handlers have to have been military working dog handlers for a minimum of a year; they then spend six additional weeks in a CTD course—four weeks at Lackland, two weeks at Yuma. The dogs are trained as combat trackers from the start. They begin tracking at distances of a foot or two (a second or two old) and work their way up. The oldest recorded track since the CTD program started in its most recent incarnation a few years ago is seventy-two hours, in Al Anbar Province, Iraq. Gerwin says he’s heard talk of a track up to five days old, but it’s not official.
33
DOG SENSE
In addition to their stellar noses, combat tracking dogs, like all military dogs, rely on other senses to do their jobs. Phenomenal as their noses are, soldier dogs can’t go purely by scent. A combat tracker, for instance, will use his eyes and ears to pinpoint his target as he approaches it. Patrol dogs depend a great deal on hearing and eyesight as well, especially when it comes to detecting the subtle movements or sounds of a suspect.
Like their noses, dogs’ ears are significantly more sensitive than ours, especially at high frequencies. “Dogs would describe us as having high-frequency deafness,” writes Bradshaw in his book
Canine ears have a reputation of being able to hear sounds up to four times farther than ours can. The mobility of their ears plays a role in helping locate and focus on sounds. As anyone who has ever watched a dog listen to something of great interest will tell you, a dog’s ears almost seem to have minds of their own. It’s no wonder: Dogs have about eighteen muscles helping them swivel and tilt their ears in response to sound. It’s pretty endearing to watch. Jake is adept at this ear maneuver whenever he begs for food or sits in the backyard listening for the cat.
Dogs have poor color vision compared to ours, decent night vision, and generally see a wider picture than we do because of the placement of their eyes. But how a dog sees the world is highly dependent on what a dog looks like. Dogs with longer noses, like most military working dogs, tend to have more photoreceptors crowded together in a horizontal streak across the eye. This “visual streak,” as it’s called, makes for better panoramic vision, with a field of vision that extends up to about 240 degrees (as opposed to our full frontal 180). Dogs with this kind of vision can even have some awareness of what’s going on behind them. But don’t ask them to focus on anything closer than ten to fifteen inches in front of their noses. Their eyes aren’t set up for that kind of vision. Dogs with shorter noses likely do better with closer vision. Their vision cells are packed in more of a circular shape, making for a narrower field of vision and more visual acuity up front.
This may explain why retrievers retrieve and lapdogs, with their big forward-looking eyes and their small snouts, like to sit on your lap and look at you.
Scientists are continuing to investigate the eyes, ears, and noses of dogs. And beyond the realm of these senses, they’re reaching out to get to know more about dog psychology, including how dogs think, feel, solve problems, and why they behave the way they do. Canine cognition is a relatively new field that’s burgeoning with enthusiastic scientists eager to plumb dogs’ minds for things we’ve wondered about but never explored before.
34
PLUMBING A DOG’S MIND
The heart of the Duke Canine Cognition Center is the dog lab. Unlike many laboratories that use dogs as guinea pigs for research, there is no pain in this lab. There aren’t even cages. In fact, the lab looks like a small dance studio. The white floor is striped with an assortment of tape colors; red, green, yellow, and blue. The dogs who come here enter with their owners, stay within feet of their owners, leave with their owners, and inevitably get treats and lots of attention during the studies. It’s Center Director Brian Hare’s idea of “an awesome place to learn about dogs.”
It’s late morning, and Hare, assistant professor of evolutionary anthropology and cognitive neuroscience, warns me that he just had cake from Costco and a coffee. “I’m totally ADD, I warn you. I’m really excited about a lot of things,” he tells me, blue eyes glittering. For the next hour, Hare talks fast and nonstop about the dog lab as he careens about his office. There’s something about his energy, his look, and demeanor that keeps reminding me of Brendan Fraser’s George of the Jungle—only Hare’s rendition holds advanced degrees, has earned great respect in the world of academia, and has the tremendous responsibility that goes along with founding and running a major research facility at one of the nation’s top universities.
This lab is one of a few dog cognition labs that have opened at universities in the United States in the last several years, including one run by Alexandra Horowitz at Barnard College. Until the late 1990s, little attention was paid to the topic of canine cognition. Primates were the primary animals being studied for cognition. But “now it’s like out-of-control exciting, trying to unlock the secrets of a dog’s mind. Now everybody is so super-excited by this research on dogs, from psychologists to anthropologists to the average American dog lover,” Hare says as he swipes his hands through his shock of thick, wavy hair.
Hare and his staff had just written a grant to the Department of Defense when I visited. He admits he’s never worked with military dogs before, but he has many ideas about how his center can help advance the understanding of dogs in a way he thinks would benefit the military dog program. He’d like to develop a cognitive test for dogs who have been involved in stressful situations, like deployments. He also wants to be able to put together a system so handlers can check their dogs for stress in the field by methods other than simply looking at behavior. This involves testing cortisol levels in conjunction with core body temperatures, as taken by a thermal imaging temperature gun.
In addition, he’d eventually like to be able to use the results of an ongoing study on something called “laterality bias” to help improve accuracy of detector dogs. “Dogs tend to go to the right. A lot tend to stay to the right of what they’re searching,” Hare explains. “It’s something you should know about your dog before you send him to find explosives, if he favors one side over the other. Don’t you think that’s important information?”
I’m not sure what the Department of Defense thinks of Hare’s ideas, but even if he doesn’t get the grant the first time, the DOD should be prepared for more grant proposals in the future. “We want to help save money and dogs and save lives, and we’ll keep trying,” Hare says.
He and his graduate students are running several studies concurrently. This helps explain the colorful stripes
