Patrick was a bomb-detection dog designed to work on a six-foot leash. Gunny Knight, then chief dog trainer at II MEF, worked hard on Patrick's off-leash skills. Patrick was one of the first PEDD dogs he trained this way. "The barrier had to be broken."

The dog was a typical Malinois. "He was all heart; he put everything into what he did, and he loved you to death," says one marine corporal, who had hoped to deploy with Patrick.

Nothing fazed this dog. During one firefight, Patrick lay beside his handler, Corporal Charles "Cody" Haliscak, in the tall gra.s.s as Haliscak and the rest of the squad engaged the Taliban. But Patrick wasn't lying there cowering. He was lying there eating gra.s.s as the bullets screamed by.

On May 9, 2011, Patrick and Haliscak were on a mission in the southern Helmand Province. With them were a minesweeper engineer and an explosive ordnance disposal (EOD) technician. The purpose was to check out a small IED-a toe-popper-that had gone off earlier that day. It didn't harm anyone, but they needed a dog's nose to clear the way back to the area. The dog went first, off leash, then the engineer with his metal-detecting device, followed closely by Haliscak and the EOD tech. leash, then the engineer with his metal-detecting device, followed closely by Haliscak and the EOD tech.

It's common knowledge among people who have dealt with IEDs in the last few years that where there's one, there are two. Where there are two, there are four. Knight says the situation has been dramatically worse in recent months. Before, you might find a small field with one IED. Now there could be ten in that same area. (The Yuma course has adjusted training methods to take this lethal factor into account.) Haliscak had a feeling that something else was out there along their path, and he stopped his team. He told the two men he would let Patrick work this one. Patrick, tail high and wagging, walked up the path, searched one corner of the poppy field that lay ahead, crossed the path, and searched the other end of the poppy field. He shimmied around and made his way to where two paths met-exactly where the team was going to be walking. There, about fifteen feet away from the men, he responded to an explosive scent as Haliscak had never seen him respond before. Patrick's usual style was to get excited, tail wagging hard, sniffing the area with great focus. Then he would sit or lie down in final response. This time, Patrick dispensed with the preliminaries and lay down immediately.

Haliscak figures his dog's last thought was "Oh, toy!!!" ("That toy was everything to him," he says.) The explosion knocked Haliscak and the two other men off their feet. They had no idea what had happened. They thought they were going to get ambushed, so they prepared to fire. When there was no ambush, Haliscak looked for Patrick. He was nowhere to be seen. The handler started searching in a circle around where the blast had gone off. As a hunter, he is used to looking for downed animals. He peered through his rifle's 4X scope. In the distance he saw that the gra.s.s in a field was bent over. Then he saw Patrick's body, or what remained of it. where the blast had gone off. As a hunter, he is used to looking for downed animals. He peered through his rifle's 4X scope. In the distance he saw that the gra.s.s in a field was bent over. Then he saw Patrick's body, or what remained of it.

"At that point I lost it." Haliscak, who had a high-grade concussion from the explosion, tried to run over to his dog, but the EOD tech stopped him. It was enough death for one day. The EOD tech and the engineer got close enough to see there was nothing to be done. They did their post-blast work on the IED and the other one from the morning. It was nearly nighttime when the two men put Patrick on a piece of canvas, covered him up, and carried him back to the patrol base. Haliscak had known the dog for three years, been his handler for one and a half years. "I lost my best friend. He was my hero. Without him and his great ability to work off leash, I'd be toast."

Once they'd brought him back, Haliscak looked at his dog. All four of Patrick's legs had been blown off. Only his head and rib cage were intact. "It's truly terrible to see your best friend like this."

Dual-purpose dogs are officially considered on-leash dogs. It's thought that the patrol part of them is too dangerous to let go off leash, so they don't receive off-leash detection training during boot camp, and often are not even at their home bases. Some handlers work on it on their own-particularly handlers with kennel masters who are wise to its benefits. But it's still far from standard procedure.

Gunny Knight has been working these dual-purpose dogs off leash for a few years-since before it was even a remotely accepted technique. "I knew this was right. When I know I'm right, a thousand people can think I'm wrong, but I stand alone and know I'm right. leash for a few years-since before it was even a remotely accepted technique. "I knew this was right. When I know I'm right, a thousand people can think I'm wrong, but I stand alone and know I'm right.

"I believe in a verbal leash. Your leash may be six feet and leather, but mine comes out of my mouth."

Single-purpose bomb dogs, like EDDs, IDDs, TEDDs, and SSDs (see chapter 10 chapter 10 if you have not retained every letter of every acronym of every MWD job) are trained to work off leash. But these are usually sporting breeds, like Labrador retrievers, and they are not trained to attack. They can be trusted not to maul anyone in their path as they trot around sniffing out IEDs. if you have not retained every letter of every acronym of every MWD job) are trained to work off leash. But these are usually sporting breeds, like Labrador retrievers, and they are not trained to attack. They can be trusted not to maul anyone in their path as they trot around sniffing out IEDs.

It's estimated that with our current situation in Afghanistan, about 95 percent of a dual-purpose bomb dog's job is sniffing out explosives-not going after bad guys. Having a bomb-sniffing dog with off-leash capabilities makes sense. The farther from the handler and other troops a dog is when alerting to an IED, the safer for everyone. Except the dog, of course. It's called stand-off distance. Some might argue that this isn't very kind or humane, that these dogs don't realize the dangers and we're sending them out as canaries in a coal mine-almost as sacrifices.

But with the dog out front, even on leash, he's always the most endangered. The idea behind using soldier dogs is that they save lives by detecting explosives before someone can get killed by one. If a dog ends up dying while the men and women behind him live, he will be greatly mourned and remembered as a hero.

n.o.body wants to see a dog die. "It just sucks. It's a s.h.i.tty situation," says Master Chief Thompson. "It hurts a lot. Just about as much as it does to lose a handler."

Gunny watches as Navy Master-at-Arms Second Cla.s.s Joshua Raymond tries working his dog Rex P233 off leash for the first time while looking for roadside explosives. The dog doesn't want to get more than ten feet away from Raymond. The handler explains that he's not allowed to have his dog off leash at his home base.

"We can get another Rex," Gunny tells him, "but we can't get another you. Parents who lose their son or daughter out there, it stays with them for the rest of their life. Children who lose a parent, it's tragic. But tough as it sounds, if your dog dies, sad as that is, you get to come back and take out Flea Biscuit Two and start all over again."

Raymond and Rex walk down the hot dirt road, no shade in sight, just rocks and sand and dried dirt, with the occasional bit of plucky scrub poking through. Rex goes on in front about twelve feet, but then turns around and waits for his handler. The dog is accustomed to feeling the end of the leash well before now.

"Put your toy away, show your dog your hands," shouts out Gunny as Raymond keeps walking. "Tell him 'I don't have it, but there's a way of earning it,' and you gotta send him back down there. Good boy, keep going, good boy, keep going! Don't let him think for himself! Find that command, maybe it's 'forward,' maybe it's 'go,' use your body and step into him. The dog doesn't know he's allowed to be that far away. There you go!

"Now back up! Now the dog takes a picture and, hey! I can be away! He can go twenty-five feet and you can back up twenty-five feet, and now you have fifty feet between you."

About twenty minutes into it, the dog looks like he's getting kind of used to the idea of being off leash. He's walking down the road and off to the sides with more confidence, not stopping so often to wait for his handler. "They all want to be free, with a little guidance, of course," says Gunny. "No one wants to have something tugging on their neck all the time." kind of used to the idea of being off leash. He's walking down the road and off to the sides with more confidence, not stopping so often to wait for his handler. "They all want to be free, with a little guidance, of course," says Gunny. "No one wants to have something tugging on their neck all the time."

Raymond is clearly impressed with what his dog has been able to do. But it goes so much against the navy protocol he has been trained to follow that he can't imagine being able to "get away with" using it.

Gunny explains that inside the wire (on an FOB), leashes are mandatory. "But I'm here to tell you for a fact that you are authorized to not only work your dog off leash here, but also when you go outside the wire in Afghanistan. If anything ever happens, call Master Chief Thompson. I guarantee he'll offer his career to back you up. So will I.

"If you find something out there, no one's going to be like 'Hey, leash up!' I guarantee, in fact, that you will get an extra scoop of mashed potatoes and a tent with AC for you and Rex."

Because of the off-leash capabilities being taught here, Gunny and his staff go a step further than the usual deferred response training. When a dog responds to an IED, the people who teach this course don't just want the dog to stay there staring at it until he gets paid. "In the real world, the handler's not going to walk way over to where the dog is responding," Porras says. "The dog has to be able to leave the odor and come back to you. It's safer all the way around."

It's not that hard to teach, as it turns out. The dog gets his million-dollar reward only when he comes back to the handler-and not when he responds to the explosive. Getting strong on the recall command ("Come!") can serve these dogs well for other reasons as well in Afghanistan. Feral and stray dogs are commonplace, and dogs have gone MIA chasing after them. As well, dirt roads can appear seemingly out of nowhere, with surprising traffic. million-dollar reward only when he comes back to the handler-and not when he responds to the explosive. Getting strong on the recall command ("Come!") can serve these dogs well for other reasons as well in Afghanistan. Feral and stray dogs are commonplace, and dogs have gone MIA chasing after them. As well, dirt roads can appear seemingly out of nowhere, with surprising traffic.

"You don't want to let your dog be done in by these dangers," Gunny Knight says. "There are enough of those as it is. A whole lotta s.h.i.t can go wrong out there."

28

HEAT

Air Force Technical Sergeant Adam Miller walks with his German shepherd, Tina M111, down a dirt road toward a small village, rifle poised. On the right, a white mosque topped with blue and gold. A billboard asking for help for Afghan schoolchildren. To the left, a service station with one nonworking gas pump. A crashed, abandoned pickup truck. Up ahead, several mud-walled buildings, some small, a few two-story. A heap of concrete walls from what looks like a bombed-out building. Several stalls making up a tiny marketplace. In the background, intermittent gunfire.

Miller and his dog walk on-Miller wearing full kit, Tina in harness and leash, which attaches somewhere on Miller's beltline so his hands can be free to use his rifle. It's 11 A.M. A.M., 114 degrees. Suddenly more gunfire. "The dog's down!" shouts someone on his team, and without hesitating, Miller reaches down to Tina, hoists her over his left shoulder, and with rifle still ready to take out anyone intent on harming him or his dog, moves a little faster now, toward shelter, anything that will protect them while he tries to save her. toward shelter, anything that will protect them while he tries to save her.

Within two minutes, they make it to a cube-shaped mud-and-concrete building-more of a hut, really. They disappear inside.

This was not in the script. What just happened? I jog over to look in through a window opening, and there's Miller crouched over his dog, working furiously to fix her. This was supposed to be a simulation. We're at the Canine Village just a couple hundred meters away from the dog kennels where we started the day at YPG. But there on the ground, incongruously-sickeningly-is Tina's severed leg. It seems to have been blown completely off her body, and there's an IV flowing into it. How in G.o.d's name did this happen?

And why would you put an IV in a severed leg, anyway? I try to look at Tina. She is lying down, and the earth beneath her is wet. Miller is wrapping bandages around her and talking to her. I can only see her front end, but her face does not look like the face of a dog whose leg is two feet away from her. Miller moves, and I see that all four limbs are firmly attached to Tina. Then in the corner of the room, I see someone looking on. She offers Miller advice about the wrap. In a moment, she suggests he do something with the IV on what's called a Jerry leg around here.

(A Jerry leg is a realistic, large, furry, fake dog leg that handlers can use for practicing placing IVs, bandaging, splinting, and giving injections. Complete Jerry dogs are also used for training. They have an artificial pulse and expandable lungs for mouth-to-snout resuscitation. There are also dogs that can be intubated, but the program doesn't currently have any of those.) Predeployment training does not get much more realistic than this. Miller would later tell me that he was exhausted when he got Tina to the building, and his adrenaline was pumping almost as it would have in a real-life war emergency with Tina. "It's the best canine training I've ever had. The hardest, too," he says. "If this doesn't prepare you for Afghanistan, nothing will." this. Miller would later tell me that he was exhausted when he got Tina to the building, and his adrenaline was pumping almost as it would have in a real-life war emergency with Tina. "It's the best canine training I've ever had. The hardest, too," he says. "If this doesn't prepare you for Afghanistan, nothing will."

The woman who is helping Miller patch up his dog is Army Captain Emily Pieracci. She is a veterinarian, and one of her main jobs is to prepare handlers here in every aspect of emergency care possible, as well as in the prevention of problems to begin with. She also makes sure all dogs who come through here are ready for deployment-medically fit and not suffering from heat casualties.

Pieracci grew up with dogs. Her mother was a police dog handler for the Washington State Patrol. Pieracci graduated Washington State University's veterinary school in 2009 and spent several months working in the private sector in the field of emergency medicine in order to pay back her student loans.

She joined the army in 2010. She has found her calling. "The army offered something different from regular civilian practice. I got to jump out of airplanes, shoot weapons, and get lost doing land navigation. I could be a vet and also do a lot of active stuff that didn't involve veterinary medicine." (The army also repaid her vet school loans, which in this economy was a huge blessing.) Within her first month at Yuma, she knew this was the place for her. She loves working with the handlers and their dogs. "I could not imagine being anywhere else other than the military. To me, this job carries so much meaning. I have such a strong sense of purpose when I care for these dogs. Keeping them healthy saves our troops' lives. It's both powerful and humbling all at the same time."

Pieracci enjoys the heat here, too. But it's this very heat that can also do in the best dogs. Heat injuries among working dogs are not uncommon here or at Lackland or in Afghanistan. On warm days, handlers take their dogs' temperatures (rectally, with digital thermometers; a dog's normal body temperature is between about 101 and 102.5) every two hours, sometimes more. But temperature tolerance can vary greatly. It's not necessarily how hot the dogs get, but how well they can compensate. One MWD went down out here at only 104. Some dogs. .h.i.t 109 and do fine after they get cooled off quickly. It all depends on the individual dog. Just as important an indicator as temperature, or more so, is how a dog acts. also do in the best dogs. Heat injuries among working dogs are not uncommon here or at Lackland or in Afghanistan. On warm days, handlers take their dogs' temperatures (rectally, with digital thermometers; a dog's normal body temperature is between about 101 and 102.5) every two hours, sometimes more. But temperature tolerance can vary greatly. It's not necessarily how hot the dogs get, but how well they can compensate. One MWD went down out here at only 104. Some dogs. .h.i.t 109 and do fine after they get cooled off quickly. It all depends on the individual dog. Just as important an indicator as temperature, or more so, is how a dog acts.

As Pieracci explains it, heat injury has three categories: heat stress, heat exhaustion, and heat stroke. The signs progress very rapidly, and heat stress and heat exhaustion can be missed by handlers if they are not looking for these. Heat stroke is the most severe form. Signs include rectal temps above 108, unwillingness to work, lethargy, vomiting, diarrhea, uncontrolled panting, and seizures.

Reaching a level defined as heat stroke is different for every dog. But most military working dogs have very high drive, which works against those looking out for them; these dogs would rather work than not. That means handlers have to be extremely vigilant for early warning signs.

Dogs here always have patches shaved on their front legs. That's for easier access to the cephalic vein if a dog goes down during training. It's a precautionary measure Pieracci takes to save time in the field during an emergency, and she encourages handlers to shave this area every two weeks while deployed. She uses the vein to administer IV fluids, which help cool the dog quickly, support stable blood pressure, and help avoid shock. On deployment, if no medics or vets are around, the handler will have to do this. That's why they insert all IVs during veterinary procedures. It helps keep them ready just in case they need to act quickly on their own. why they insert all IVs during veterinary procedures. It helps keep them ready just in case they need to act quickly on their own.

Pieracci says that dogs who go through Yuma tend to fare better with heat injuries downrange than other MWDs. That's mostly due to handler knowledge. Part of the reason the dogs train out here is to show handlers what their dogs look like when they're getting hot: Does the dog seek shade? Does she quit working, or will she keep working no matter how hot it gets? Having the handlers see how their dogs react in Yuma helps them identify when their dog might be overheating in Afghanistan.

Coming to Yuma also makes handlers hyperaware of the need to check dog trailers every ten minutes to ensure the air-conditioning is working when dogs are inside. (It's not very cold air, but just enough to make it somewhat comfortable-or at least tolerable.) "There's a side of me no one wants to see if you kill your dog in one of these," Gunny says as he knocks on an empty trailer.

In late September 2011, two marine IDDs were being transported to Yuma from Fort Bragg, North Carolina. The contractors (the dogs were not with their handlers) responsible for the dogs' care during transport stopped overnight in Phoenix and allegedly left the dogs in the travel trailer unattended. They found IDD Ace dead the next morning, and IDD Max was in critical condition.

According to Pieracci, Max was taken to a Phoenix emergency veterinary hospital, where he received three blood transfusions and ma.s.sive amounts of fluid and medication. He was in kidney failure and bleeding internally from the heat stroke. He was severely dehydrated, and the vets were worried about his brain swelling from the high levels of sodium in his blood. He remained in critical condition for ten days, but he pulled through.

"He was a real fighter. He was discharged just three days ago and is on his way to Lackland, where he will most likely be adopted out. I don't think he'll ever be able to deploy to a hot environment again after the severity of his case. He may have some long-term kidney and brain damage, and quite frankly, he's been through enough," says Pieracci. "He deployed in 2009 and 2010, and I know he served his country honorably. He deserves a nice comfy couch for as long as he's got left, if you ask me." She has never met Max, but she was on the phone with the Phoenix vets every two to four hours while he fought back from the brink of death. "I feel quite attached to him even though I've never met him. I would love to meet him before he retires, but I'm not sure that will happen."

Those contractors may want to stay out of Gunny Knight's way.

29

THE END OF THE ROAD?

More parachutists drop in front of us as we round a bend later toward the kennels. "Hollywood, that's what they are," Gunny spits.

"I don't know how many frickin' millions of dollars they spend every year to let these guys jump out of planes. Dogs save so many lives out there, this course has saved untold numbers, and as of now, we have no funding after October 2012."

Finally, perhaps, we've come to the reason he feels disdain for the jumpers.

It costs the DOD about $750,000 a year to run the IASK Course. Some 225 handlers go through the course annually. Despite the tremendous (if unquantifiable) success of the course, it's on the chopping block because of the same major budget cuts causing pain everywhere in the military. The program is currently considered a Tier III course, which means it's looked at as "extra" in times of budget crises.

But what is $750,000 when it comes to saving lives? If you have to put a life in terms of dollars, it costs the government $400,000 to $500,000 in death benefits for every soldier, sailor, airman, or marine killed in action. The Defense Department would have been sh.e.l.ling out more money for the lives Patrick saved that day than it costs to run the IASK Course for an entire year. $500,000 in death benefits for every soldier, sailor, airman, or marine killed in action. The Defense Department would have been sh.e.l.ling out more money for the lives Patrick saved that day than it costs to run the IASK Course for an entire year.

"It's astronomical the number of lives that are being saved because of this Yuma program," says Bowe. "And I will panhandle to get this if I have to."

The idea is for the course-which began in late 2005 as an "urgent need" program-to become a formal, required course. This would guarantee funding for awhile. Bowe had exhausted two of three options by the time this book went to press. "The program absolutely must not, cannot go away," Bowe says. "Too many people and dogs will die."

I would not be surprised if dogs around here smell a little extra fear these days.

30

THE SCIENTISTS WEIGH IN

ON NOSE POWER

The mind of a soldier, the nose of a trained dog: a perfect partnership," dog behaviorist and anthrozoologist John Bradshaw wrote me one day during a round of e-mails about a dog's sense of smell. It was a refreshing change from the mound of complex scientific journal articles that had acc.u.mulated on my desk about the subject of a dog's sense of smell, including one I was trying to get through at the moment: "The Fluid Dynamics of Canine Olfaction: Unique Nasal Airflow Patterns as an Explanation of Macrosmia."

If dogs had noses like yours or mine, they would have an utterly different and diminished role in today's military. The Department of Defense would still likely use some dogs for patrol purposes (although there are currently no "patrol only" dogs), but as it is now, those skills are rarely called upon. And say what you will about companionship or the value of a unit having another set of eyes, we are involved in a war where IEDs are the number one killer. If soldier dogs didn't have such excellent noses, they would be a rare breed.

Dog owners are all too aware that there's something different about the way dogs sense the world. For instance, there's the old "Nice to meet you! Now I'll sniff your crotch and learn more about you!" business that embarra.s.ses many of us when we have company over. And it's a dog's sense of smell that's at least partly responsible for why walks that would take ten minutes without a dog take at least twice as long (especially with a male dog) if you let the dog set the tempo. On walks, I find myself asking Jake things like "How could you possibly smell that tuft of gra.s.s for an entire minute? Can't you see it's just gra.s.s?"

In a way, dogs are wonderful travel companions because they do force you to slow down from the madcap pace many of us maintain on vacation. We try to fit in too many activities, too many sites, and then we return feeling more exhausted than when we left.

With a dog, though, you have to stop the car more frequently than you might normally, so the dog can have a bathroom break and stay comfortable. And you can't just race around from one attraction to another when you're hoofing it with a dog. A dog will, by his very nature, force you to slow down a bit. In other words, to use a cliche I have used too many times in my talks: Dogs help you stop and smell the roses.

I never really thought too much about the literal meaning of a dog smelling a rose until I came across this description by Alexandra Horowitz in her wonderful book Inside of a Dog: What Dogs, See, Smell, and Know Inside of a Dog: What Dogs, See, Smell, and Know: Imagine if each detail of our visual world were matched by a corresponding smell. Each petal on a rose may be distinct, having been visited by insects leaving pollen footprints from faraway flowers. What is to us just a single stem actually holds a record of who held it, and when. A burst of chemicals marks where a leaf was torn. The flesh of the petals, plump with moisture compared to that of the leaf, holds a different odor besides. The fold of a leaf has a smell; so does a dew drop on a thorn. And time is in those details: while we can see one of the petals drying and browning, the dog can smell this process of decay and aging.

Since reading that pa.s.sage, and learning a great deal about dogs' sense of smell, I have been more understanding when Jake stops and spends a full minute inspecting a neighbor's hedge. I am so awed by what a dog's nose is capable of, in fact, that I try to add a little time to our walks so I don't have to rush him from his rich world of fascinating odors. That hedge is imbued with odors representing many things, including all the dogs who have preceded Jake. "Dogs read about the world through their noses, and they write their messages, at least to other dogs, in their urine," psychologist and prolific dog-book author Stanley Coren told me. Who am I to tear Jake away from his favorite news and gossip blog?

I'm now also slightly less discomfited when Jake and another dog greet each other by heading right for each other's nether regions. Chances are the dogs are learning far more about each other than the other dog's owner and I are learning about each other; we make idle chitchat and try very hard not to notice our dogs' utter fascination with each other's a.n.a.l area and s.e.xual organs; exactly what the dogs are learning about each other, and what they do with that information, has yet to be figured out by science. But it's very likely far beyond "Nice weather we're having, eh?" "Yup, how 'bout them Giants?" It's probably more along the lines of "How old are you, and what's your personality like, and what did you have for dinner, and are you gonna be nice or a jerk?" Giants?" It's probably more along the lines of "How old are you, and what's your personality like, and what did you have for dinner, and are you gonna be nice or a jerk?"

The canine proclivity for sniffing out what we might consider the more intimate olfactory signals may have helped the Allies in World War II: n.a.z.is stationed along the Maginot Line were using dogs as messengers. French soldiers attempted to shoot the dogs, but the dogs were quick and stealthy.

Enter a French femme fatale. She was a little thing, a messenger dog who had just gone into heat. She went on her mission, and when she returned to her post that evening, about a dozen German military dogs were close behind. It was a small victory played out in the battlefields. Toujours l'amour.

Figures abound about how much better a dog's sense of smell is than ours. There are so many variables that it's almost impossible to quantify. I've seen figures indicating that it's from 10 to 100 to 1,000 to 1,000,000 times better. Bradshaw explains that dogs can detect some, if not most, odors at concentrations of parts per trillion. The human nose, by contrast, is lucky to get into the parts-per-billion range and is often relegated to parts per million. That makes a dog's nose between 10,000 to 100,000 times more sensitive than ours. The range is obviously very wide, and the sensitivity depends on variables like the dog and the odor. Research continues.

Coren gives an example of what this extra sensitivity looks like. Let's say you have a gram of a component of human sweat known as butyric acid. Humans are quite adept at smelling this, and if you let it evaporate in the s.p.a.ce of a ten-story building, many of us would still be able to detect a faint scent upon entering the building. Not bad, for a human nose. But consider this: If you put the 135-square-mile city of Philadelphia under a three-hundred-foot-high enclosure, evaporated the gram of butyric acid, and let a dog in, the average dog would still be able to detect the odor. let it evaporate in the s.p.a.ce of a ten-story building, many of us would still be able to detect a faint scent upon entering the building. Not bad, for a human nose. But consider this: If you put the 135-square-mile city of Philadelphia under a three-hundred-foot-high enclosure, evaporated the gram of butyric acid, and let a dog in, the average dog would still be able to detect the odor.

If a dog can detect BO in such tiny amounts, imagine what it's like for a dog to be immersed in a world of sweaty humans in a far smaller s.p.a.ce. Coren was recently able to observe one of his dogs in just such a situation, when he was out picking up a friend at the gym. He brought along Ripley, his young Cavalier King Charles spaniel, whom he held in his arms. When they entered the gym, Ripley's nose flew up in the air and he went stiff-a clear-cut case of olfactory overload.

This same dog would go on to nearly blind Coren in one eye the week before we spoke in October 2011. Coren had fallen asleep in his favorite chair. The nine-month-old Ripley, being both a lap dog and a face-licker, took advantage of the moment and, in the process of enthusiastically slathering Coren's face, got one of his nails lodged in the inner margin of Coren's left eye. The dog, unable to extract it, used his other paw to press against Coren to dislodge it. When I interviewed him, Coren's eye had ruptured, the iris and the lens were gone. He'd had two surgeries, with two or three more to go "before they give up," he said. He takes it in stride. He would have started to go blind in that eye from a progressive eye disorder within a couple of years anyway, so he says the dog just speeded up the process. I wondered if maybe the dog had some sense of his eye problem and was trying to help him, like dogs I have read about who try to chew away cancerous moles. Coren, perhaps not surprisingly, does not give Ripley any accolades as a diagnostician or surgeon. perhaps not surprisingly, does not give Ripley any accolades as a diagnostician or surgeon.

A handy way a dog's olfactory sensitivity manifests itself is with something called odor layering. This enables a dog to separate a chosen scent from the "background noise" of all the other scents, much as humans could visually sort a bunch of miscellaneous items spread out on the ground. Dog handlers have variations of a.n.a.logies for odor layering, and they're all based on food. Probably the most common: We humans can smell the pizza. A dog can smell the dough, the sauce, the cheese, and all the spices and toppings. A dog might even be able to smell the components of each of those. Not just dough, but flour and yeast. Not just sauce, but tomatoes and basil and oregano. Some handlers and dog trainers use chocolate cake as an example, others use stew. But it all boils down to the fact that dogs have very sensitive noses that are capable of teasing apart scents as you and I could never dream of doing.

As Navy Lieutenant Commander John Gay was driving me to the submarine in Norfolk to see little Lars do his detection work, he told me that even his late boxer, Boris, was adept at odor layering in his heyday. (Boxers are generally not renowned sniffers.) Gay's wife used to bake all kinds of m.u.f.fins and cookies, and Boris would show no interest. But when she made a particular kind of cookie that Boris was allowed to eat, he waited eagerly by the oven door, even though she gave no indication the cookies were for him. Oh, and the dog could also smell flies. Flies.

We humans have, not surprisingly, found plenty of ways to put this exquisitely sensitive olfactory apparatus to work in detecting odors of importance to us. Some of them seem nothing but miraculous. odors of importance to us. Some of them seem nothing but miraculous.

Dogs are proving very adept at sniffing out a variety of cancers, including lung, ovarian, skin, and colon malignancies. Specially trained dogs can predict seizures in those p.r.o.ne to them, or sense dangerous changes in blood sugar levels in diabetics. Dogs can detect pests, including bedbugs and termites. They've been used to sniff out cell phones in prisons, oil and gas pipeline leaks, flammable liquid traces in arson investigations, toxic molds, diseases in beehives, and contraband foodstuffs. They can tell when a cow is going into heat. They can even use their noses to find cash. Jake has shown no talent for this I'm afraid.