It would be tough to conceive of a better smelling machine than a dog. Its nose extends from the nostrils to the back of its throat, giving a dog an olfactory area 40 times greater than a human’s. Dogs have some 300 million olfactory receptor cells; humans have six million. More to the point, 35 percent of a dog’s brain is assigned to smell-related operations. A human brain assigns only 5 percent of its cellular resources to smelling, and given the low esteem in which we hold our noses, even that sounds like an overinvestment.
It’s not just a matter of quantity, either. A dog’s nasal mechanism doesn’t work the way a person’s does. For one thing, the functions of breathing and smelling aren’t all jumbled up together, the way they are for us. When air enters a dog’s nose, it splits into two separate paths—one for breathing and one for smelling. And when a dog exhales, the air going out exits through a series of slits on the sides of a dog’s nose. This means that exhaled air doesn’t perturb the dog’s ability to analyze incoming odors; in fact, the outgoing air is even thought to help new odors enter. Even better, it allows dogs to smell continuously over many breathing cycles—one Norwegian study found a hunting dog that could smell in an unbroken airstream for 40 seconds over 30 respiratory cycles.
Remember the kid in school who could wiggle his nose without touching it? Well, dogs can wiggle each nostril independently. This is not just a party trick. It helps dogs locate precisely where a particular odor is coming from, which is not a bad thing if you’re trying to find a well-hidden bomb.
In a contest for best all-around nose in the animal kingdom, however, dogs might not take top prize, says Paul Waggoner, associate director of the Canine Detection Research Institute at Auburn University. The elephant is a walking dictionary of odors. Rats and mice smell at least as well as dogs, and jackals are simply uncanny. For obvious reasons, none of these animals are serious candidates for a bomb-detection job. Where dogs ace the competition is attitude. “No other animal comes so well prepared for us to do what we need them to do,” says Waggoner. “They want to please us.”
Among dogs, the best breeds for finding bombs may be German shepherds, Belgian Malinoises (also known as Belgian shepherds) and Labrador retrievers, more for their tireless work ethic than any special olfactory prowess. Shepherds are so-called “play reward” dogs. There’s a shepherd named June training alongside Merry at MSA’s hangar. “She will work all day for her tennis ball,” says Mike Wynn, MSA’s director of canine training. Labs, perpetually hungry, are “food reward” dogs. Shepherds will accept criticism; Labs won’t—the stress of not measuring up takes the starch right out of them.
What about bloodhounds, you say? True, a bloodhound will follow a straight-line scent—an escaping convict, say —as if it’s being pulled by a string. “But they’re way down on the intelligence scale,” says Wynn, who worked with bloodhounds as a patrol dog handler with the Connecticut State Police. “Also, they stink like livestock.” Golden retrievers can outsmell everybody, but it’s tough to get them to buy into the system. “They’re so intelligent that if they don’t want to do something, they just don’t do it,” says Wynn. Some breeders are looking into Glabs—a mix of golden retriever with Labrador—to get the best of both breeds.
Bomb dogs may be the most overlooked troops in the hazy, undeclared war on terror. Until 9/11, they were mostly ignored because there were very few of them. MSA started in 1987 with a handful of dogs. By 2000, it still had only 15 teams. Then the towers fell, and from their dust rose an instant national bomb consciousness, even though it wasn’t a bomb that brought the towers down.
“After 9/11 there was just this explosion of interest in understanding the gaps in bomb detection and detection technology,” says Kenneth Furton, a research chemist who also serves as chairman of a group called SWGDOG—the Scientific Working Group on Dog and Orthogonal Detector Guidelines. “To some extent, people got interested just to show they were doing everything in their power to counter any imaginable threat. There was even a private school here in Miami that had its own private bomb dog.”
Bomb dogs are everywhere now—banks, airports, trains, post offices, sports stadiums. If bomb dogs are overlooked today, it’s because they have blended so seamlessly into the post-9/11 landscape. An explosive detection canine in an airport today doesn’t stand out anymore than a collie chasing a stick on a suburban lawn. Part of the reason people don’t notice bomb dogs is they tend to like them.
Several years ago, one Midtown Manhattan bank started using two dogs to check every package that went into and came out of the building. “People love having the dogs around—I don’t know anyone who hates dogs,” a security official at the bank says. “On the other hand, a police officer with a bulletproof vest and an M16 makes them nervous. It’s a no-brainer.”