He’s the world’s most advanced mobile detection system to defend an area from potential attack. Capable of sniffing out someone carrying a bomb in a crowd of people ten thousand strong.

In other words, he’s a Vapor Wake dog, the end result of pioneering research begun 16 years ago in the Canine Performance Sciences (CPS) program at the Auburn University College of Veterinary Medicine in Auburn, Alabama. Vapor Wake has a training process so scientifically rigorous and technically developed that Auburn was granted a patent for it in 2015.

The science behind the patent is based on the physics of fluid dynamics, which shows that people in motion leave a thermal plume in their trail, much like the wake of a boat: a heat signature that’s invisible to the naked eye. Odors and particles coming off those people are sucked into the aerodynamic plume created by forward motion.

What does this have to do with sniffing out explosives?

When bombs degrade, they release particulates denser than air. If someone is carrying that bomb, traces of those particulates are caught in their heat signature plume and broadcast behind them. A Vapor Wake dog is trained to catch that scent.

Dogs are born bomb sniffers. They have more than 300 million sensors in their snouts, compared to just 6 million in a human nose, and the portion of their brain dedicated to their sense of smell is almost 40 times greater than in the human brain. And because their nostrils operate independently of each other, they can determine the direction of odor, and are able to detect scents in parts per trillion.

One part per trillion is the equivalent of sniffing out a single drop of fruit juice in 10 Olympic-size swimming pools.

So how do Vapor Wake dogs differ from traditional bomb-sniffing dogs?

“Traditional explosive-detection dogs are trained such that they search objects and areas for target odors,” L. Paul Waggoner, PhD, codirector of Auburn’s CPS program told NEWStat. In other words, static objects, such as baggage and vehicles. “Vapor Wake dogs are trained . . . to sample the aerodynamic plume generated by the movement of persons through a space, and if they detect an explosive odor, track that odor to its source.”

Vapor Wake dogs are literally born at Auburn and receive environmental and socialization training for their first year. The dogs are then sent to a company called VWK9 in Anniston, Alabama, for further training until they’re about 18 months old. Then they’re paired up with a handler for a joint seven-week behavioral training course. VWK9 is the Auburn University licensee of Vapor Wake technology and provides Vapor Wake dog-handler security services on a contractual basis.

Waggoner says that Amtrak was an early adopter, fielding multiple Vapor Wake dogs for mass transit security. Other clients include the Chicago Police Department, Major League Baseball, and the Disney Corporation, which has deployed Vapor Wake teams to the streets of Disney World. Microsoft contracts Vapor Wake teams for corporate events.

They’re like the Men in Black of working dogs—the best of the best.

“Generally speaking, only a small portion of dogs capable of performing traditional detector-dog work are capable of being successfully trained for Vapor Work operations,” Waggoner says. “Keep in mind that Vapor Wake dogs are required to work in exceedingly busy, noisy, and dynamic situations such as mass transit and large event venues [such as those used for concerts and sporting events].” Most dogs would get too anxious or distracted in that kind of urban clutter and confusion.

That’s one reason that Labrador retrievers are the only breed of dog to be trained as Vapor Wake dogs.

Their friendly, unthreatening, and relatively unflappable disposition means they remain calm under pressure. Plus, the public views them as very approachable—people aren’t afraid to walk past them in a public place, which makes it easier for Vapor Wake dogs and their handlers to work a crowd.

As for how many bombs Vapor Wake dogs have successfully sniffed out, that’s hard to know—Vapor Wake dogs are anonymous heroes.

Waggoner says information on the detection of explosives or explosive devices usually isn’t publicized because it provides would-be terrorists with information they can use to avoid getting caught. But, he adds, “I can say [Vapor Wake dogs] have detected actual threat materials and devices in actual working circumstances.”

As they say at CPS: Man’s best friend. Man’s best defense.