Every muscle tense, every nerve on alert, the wiry yellow labrador shot from her leash Saturday and bounded nimbly up a tortuous vertical maze of concrete slabs, rusted beams and chunks of rubble. Every few feet she stopped and sniffed the wind, then darted through another opening.

Within three minutes, Pryse, a member of the Fairfax County urban search and rescue team, had homed in on her target: a woman trapped inside a section of cement pipe. After a few extra sniffs to confirm the scent, the 6-year-old lab began barking furiously, her tail wagging with excitement.

“Whoo-whoo! Good girl!” came the muffled voice of the “victim” from inside the pipe, its entrance camouflaged with a wooden pallet. Then a hand pushed a colorful cloth tube out through the pallet, and Pryse began shaking it in a frenzy of delight. It was her favorite tugging toy, hidden with the victim to reward the dog for her success.

“To her, it’s all a game of hide and seek,” said Ron Sanders, 54, Pryse’s handler and best friend, who was waiting nearby with pats and praise. “That toy means more to her than anything in the world, even food. We use the toys to create loyalty to the victim, and we train the dogs to navigate the rubble. So when they go in there, it’s like Disneyworld with a prize at the end.”

Pryse and Sanders, a retired firefighter who lives in Lynchburg, Va, returned last week from Nepal, where the Fairfax rescue team was deployed by the U.S. government to search for survivors trapped in the massive, 7.8 level earthquake April 25 that killed more than 8,000 people.

Both were on the scene during the dramatic rescue of a teenaged Nepali boy who had been trapped under a collapsed hotel in Katmandu for five days. After he was safely extracted, Sanders sent Pryse racing straight up and into the precarious ruins to search for any other survivors, but she detected no live human scent.

Back home, they took a few days to get over jet lag, while Pryse was reunited with her canine housemates – Tomo, a 12-year-old German shepherd who retired after deploying with Sanders to half a dozen disasters, and Roxy, a 6-year-old Belgian Malinois who was too high-strung to become a reliable sniffer dog but became so attached to Sanders that he never had the heart to part with her.

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Then, on Saturday, it was back to “the pile,” as Sanders and his teammates call their permanent training site, a tower of rubble built on the grounds of an abandoned prison complex in Lorton, Va. The team trains two weekends each month, to keep the dogs ready for both disaster deployment and periodic re-certification by the Federal Emergency Management Agency.

All morning. Sanders took turns with 9 other handlers sending their dogs to sniff out volunteers hidden in pockets under the debris. Several got distracted by the scent of a woodchuck or fox, but others went straight to the human scent and were rewarded with extra-effusive whoops. Pryse was one of the quickest, and Sanders beamed with pride each time she located the scent source and began barking.

“She’s fast, she’s agile, and she’s doing what she was made to do,” he said. “We want them to rely solely on their noses, but it takes lot of training and discipline too. You have to set boundaries, get rid of distractions and develop a strong personal bond so the dog is always focused on you and the job.”

Pryse’s responsiveness to Sanders was especially evident when he took her through an obstacle course at the Lorton site, designed to help dogs handle daunting and unstable terrain. On his commands, Pryse dove into plastic tunnels, scrambled up a ladder, stepped carefully across a series of posts, inched up a see-saw until it tilted and then inched down the other side. That feat earned her an extra pat and a snack from his pocket.

Sanders, a gentle, soft-voiced man, uses simple one-word commands like Find, Through, and Drop. When Pryse or another dog disobeys or makes a mistake, he uses an escalating scale of disapproving words and tones: Uh-huh, No, Phooey, and Nein!! “If it still happens, I might give them a swat on the nose, but that is very rare,” he said. “The key is to repeat and reward, repeat and reward.”

Like all rescue dog handlers, Sanders knows that the “fun” training is also intended to send an animal he loves, and who would do anything for him, into harm’s way. Injuries on the job are uncommon but not unheard of; dogs inside a collapsed or burning building can fall into crevices or get caught on sharp metal. Accidents also occur in training; two of the Fairfax team’s dogs are currently recovering from broken legs.

“Some people object to what we do with these dogs and say it’s inhumane. But they are doing what they love, and they are doing it better than we can,” Sanders said during a visit to his home last week. “They are taking huge risks for the potential of saving a life. I have to go into a dangerous situation and make a decision whether to send them in or not. And no one loves them more.”

Pryse is the third rescue dog Sanders has trained and deployed with over the past two decades. He stumbled into the field by chance, when a friend asked him to take care of a police sniffer dog, but it soon became an a vocation and then a passion.

He and his dogs have been sent to help find survivors after hurricanes Katrina and Sandy, an earthquake in Haiti and another quake and tsunami in Japan.

Sanders is clearly close to all three dogs who share his home. Roxy, too nervous and aggressive for other people to handle, finally calmed down under his quiet command. Tomo shared the worst experience of his career, the devastating 2010 earthquake in Haiti that killed at least 100,000 people. The Fairfax rescue team, working around the clock, managed to find and save only 16.

Sanders has never had a dog seriously injured or killed in the line of duty, but last winter he lost Ondo, a handsome older shepherd who was his first rescue partner. After retiring from years of service, Ondo accidentally swallowed a sock and died. As Sanders told that story last week, he had to choke back tears. Ondo’s stained-glass portrait hangs in the family kitchen, and his collar has been passed on to Pryse.

Now that Sanders too has retired, and his son Eric and daughter June are grown, he spends much of his free time with his canine companions, doing informal home training between the regular sessions in Lorton and the occasional emergency deployments.

They, in turn, are clearly devoted to him.

“You really have to enjoy doing this because it takes so much time and patience,” Sanders said, sitting in the kitchen as Pryse kept trying to climb into his lap for an ear rub and Tomo kept dropping a rubber ball at his feet, hoping for a game of catch. “It becomes a way of life, and they become part of your family.”

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