Published: Jul 17, 2013 6:30 PM EDT

LEE COUNTY, Fla.- When you go through security at Southwest Florida International Airport, you may notice some new security agents- on four legs!

Passenger screening canines go through extensive training to learn how to sniff out an explosive scent.

The three dogs have been working at RSW for the past six months. They live with their handlers so they can learn each other's every move. The handler looks for a change in the dog's behavior if they detect a suspicious scent.

Bob Cohen, Federal Security Director for the TSA at RSW says, "these dogs have the capability to pick up an explosive scent on a person if they are carrying any type of explosive. It's given us another layer of security for TSA, to ensure no bad guy or girl gets through with any kind of explosive to an airplane."

He says the dogs go through 12 weeks of extensive training, but it doesn't end there. "They are training almost every single day as well as working every day at the checkpoints, in the cues and here in the sterile area."

He says RSW is one of only 24 airports with these explosive detection dogs. "It gives us an added security posture that makes it not difficult, but nearly impossible to get through this airport with explosives."

Eric Bonner is Gina's handler, a labrador retriever. He's a former U.S. Air Force K9 handler and says the job takes the phrase 'man's best friend' to a whole new level.

He says, "you have to have a good working relationship between the dog and the handler. It's a bond that has to be worked through, treasured. The dog has to want to work for you, you have to want to work with that dog."

Bonner says he looks for a change in Gina's behavior when she smells something wrong. "Anything the dog does that deviates from a normal search pattern. The dog walks back and forth, kind of bebops around, then you'll see the dog throw his head up in the air, throw his head down, sniff-those are things we consider a change in behavior."

He says the dog does have some down time at home. "A dog has to be a dog so when they come home they get to run around the yard, sleep on the coach, play with anything besides a tennis ball." The tennis ball is the dog's reward while on the job. But he adds, "we like to say they can turn it off, but these dogs are searching every minute of the day. The first day I brought my dog home, she searched my entire house."

These dogs focus on the secuirty lines at the airport, while airport police K9s search other public areas at RSW. Airport officials say the dogs have never had an incident at RSW.