The science of sniffer dogs Rescuers from all around the world are converging on Haiti in the wake of this week's earthquake - and not all of them are human. Finding survivors amid the rubble of Port-au-Prince is a job tailor-made for dogs and devices. The search-and-rescue operation "appears to be unprecedented in scale," Discovery.com reports. Many of those teams, such as Virginia Task Force 1 and California Task Force 2, have been in this kind of situation before - for example, after the catastrophic Iranian earthquake of 2003 or the collapse of a Haitian school in 2008. But the magnitude of this week's disaster is so great that rescue teams who have never before gone into an international operation are being pulled into action. "This is an unusual situation," said Debra Tosch, executive director of the National Disaster Search Dog Foundation. Tosch has been doing search-dog training for 12 years, and was in the midst of a training session when I called her today. Despite all the technological advances in search and rescue, she says dogs are still "man's best friend" in the wake of a disaster. "They can cover a large area much more quickly than we can," she said. Robots and listening devices may come into play during a rescue operation, "but a dog is much quicker." The making of a sniffer dog The best breeds for this job are working dogs: Labrador retrievers, golden retrievers, border collies, German shepherds and the like. "We will test 100 dogs before one one goes into our program," Tosch said. "What we're asking them to do is not natural for a dog. How many dogs on their own would go up a fire ladder to the second story?" The dogs that make the grade are trained to recognize a specific smell: the scent of a live, not a dead, human. "We all have a common scent that says, 'Yes, I am a live human being,'" Tosch said. "We also have an individualized scent, but these dogs are trained to look for that common scent." Sniffer dogs are adept at matching up that scent with the people surrounding them - in effect, saying to themselves, "This is it ... oops, that's you ... then, this is it ... ah, there's nobody there," Tosch said. At that point, the dog barks until it receives its reward. During training, the dog is given a tug toy by the supposed victim. "That's why the dog always wants to find the victim," Tosch explained. "That's where the fun is. It's a hide-and-seek game." In the field, the dog's handler has to find a way to give the dog its toy as if it had come from the disaster victim, to reinforce the hide-and-seek behavior. And if the dog doesn't find anything, a rescue team member might have to hide amid the rubble to give the dog a chance for positive reinforcement. "We've done that," said Lt. Gery Morrison of Fairfax County Fire and Rescue in Virginia, a veteran of Virginia Task Force 1. "We've put rescuers behind a building, just a mock rescue, so that dogs will find a live person and get rewarded. Otherwise, they get discouraged." Once the dog finds a survivor, other methods come into play for the actual recovery. "It's not that dog's job to tell us exactly where the victim is," Tosch said. "His job is to tell us where the strongest human scent is." Pinpointing the victim's location The victim might well be caught under tons of rubble, and the scent could waft up through nooks and crannies to a spot on the surface yards away. Or the dog might have caught a whiff of a false positive. Nobody's perfect, not even an expert canine. "If the dog gets a 'hit,' then we'll go with some other device to get a secondary confirmation, either using a SearchCam or a listening device," Morrison told me. "If we don't get any information from those devices, then we'll send a second dog in." Search-and-rescue cameras are typically mounted on wands that can be extended to 8 feet or so, with 360-degree view control. Listening devices can pick up the faint sounds of human voices or movements within the rubble. But how do you actually retrieve the victim? That's where human hands and specialized tools come into play. Getting the victims out This time around, Virginia Task Force 1 is using a few new twists, including a heavy-duty rebar cutter that can handle the reinforced concrete found at Haitian disaster sites. "We stole that from the construction trade," Morrison said. The task force's upgraded toolbox also heavy-duty saw that can cut through 2-inch-thick steel. "Believe it or not, it looks like a Skilsaw but it cuts steel," Morrison said. As horrible as the Haitian earthquake was, there are some factors that make this search-and-rescue job easier than the typical urban situation, Morrison said: "The biggest thing that we have is the height of the buildings. We don't have the six- or eight-story buildings. They're all one-, two-, three-story buildings, so that helps us." But search-and-rescue robots aren't on the scene as much as they were in the aftermath of the 9/11 terror attacks and Hurricane Katrina. The main reason for that has to do with the characteristics of the collapsed buildings in Port-au-Prince. Morrison explained that collapses generally follow one of three models: a pancake collapse, a "V" shape or a lean-to collapse. "In Haiti, we're dealing with a pancake collapse. ... When you have the lean-to or the V collapse, you have more voided areas. The pancake doesn't have so many of those empty spaces for operating a remote device," he said. "On the other hand, the structures are more stable when they pancake. You feel more confident about putting a rescuer or a technician in there." Robin Murphy, a Texas A&M professor who heads the Center for Robot-Assisted Search and Rescue, said she didn't know of any robots currently being used on the ground in Haiti. "Ground robots are helpful for large buildings, but in general, dogs are the biggest help in finding victims in residential areas - dogs smell faster, much faster than the most agile robot can get in the rubble," she wrote in a blog posting. She said robots in the air, such as the U.S. military's Global Hawk drones, can contribute to post-disaster reconnaissance. "I'm not sure if the air traffic control problems have been resolved to permit larger aerial assets to fly," she told me in an e-mail. (In fact, a Global Hawk has been flying over Haiti for the past couple of days ... here's a video report.) Considering that the quake occurred on Tuesday afternoon, is it getting too late to find survivors amid Port-au-Prince's rubble? Not on your life, Morrison said. "We have found individuals [alive] 72 hours after the fact," he recalled. "In Turkey, we found one after seven days. The only guideline is that you go multiple days after the latest find. Also, it's the amount of devastation. Are we fruitlessly putting people in a dangerous situation?" At some point, the live-scent dogs will have to be replaced by cadaver dogs. The search teams will head home, and Haiti's rescue effort will become a recovery effort. But that point hasn't been reached yet. The dogs are still barking. Update for 10:30 p.m. ET: The National Disaster Search Dog Foundation sent along some good news at the end of this bad-news week. Here's today's news release from Janet Reineck, the foundation's development director: At 1:15 p.m. local time, an SDF Search Team in Port-au-Prince located three girls, trapped alive since Tuesday in the rubble of Haiti’s devastating earthquake. Bill Monahan and his border collie, Hunter, were searching a neighborhood near the Presidential Palace, concentrating on a large bowl-shaped area of rubble which was all that remained of a four-story building. After criss-crossing the area, Hunter pinpointed the survivors’ scent under 4 feet of broken concrete and did his “bark alert” to let Bill know where the victims were. Bill spoke with the survivors, then passed them bottles of water tied to the end of a stick. As they reached for the water, one of the girls said, “Thank you.” Highly trained rescue crews from California Task Force 2 are now working to extricate the girls from the wreckage and provide first aid. Bill and Hunter continue to search, as do the six other SDF teams on the ground in Haiti: California Task Force 2 – Los Angeles County Gary Durian & Baxter – L.A. County Fire Ron Horetski & Pearl – L.A. County Fire Bill Monahan & Hunter – L.A. County Fire Jasmine Segura & Cadillac – L.A. County Fire Jason Vasquez & Maverick – L.A. County Fire Ron Weckbacher & Dawson – Civilian Florida Task Force 1 Julie Padelford-Jansen & Dakota At Search Dog Foundation headquarters in Ojai, CA, SDF Founder Wilma Melville received the news with silent gratitude. “This moment is what SDF Search Teams train for — week in and week out — throughout their careers together. When one SDF team succeeds, all of our teams succeed. Our thoughts are with our teams in Haiti, who continue to comb the rubble into the night. Their perseverance, skill and strength in the face of extreme challenges make us all proud, and give us hope.” Captain Jayd Swendseid of CA-TF2 confirmed earlier today that the 72-member team Task Force with 70,000 pounds of rescue equipment is actively looking for victims around-the-clock. “The teams are working in 12-hour shifts so they have time to rest and recuperate. Yesterday the team put in a long and exhausting day. Roads are closed and there is a lot of debris that is making transportation difficult, but the team is managing to get to buildings and make rescues. Morale is good and supplies are sufficient so far.” The teams of CA-TF 2 are now assigned to one of two squads to enable round-the-clock searching. The Red Squad (Dawson, Pearl, and Maverick) is in rotation with the Blue Squad (Hunter, Baxter and Cadillac). The squads connected briefly with SDF Team Julie Padelford-Jansen and Dakota — deployed as part of Florida Task Force 2 — before Julie and Dakota were assigned to search a different neighborhood. SDF Executive Director Debra Tosch: “All SDF handlers are experts in reading their canines, pacing them throughout their shift to ensure the dogs are kept safe, healthy, happy and motivated. The canines are literally the Task Force’s most precious tool in the hunt for survivors: Their well-being is mission-critical.” SDF is grateful to all of our supporters around the country who are truly part of the search, having made this rescue possible.