Detection work goes to the dogs
Dogs have helped men search for prey for thousands of years. Today their marvelously sensitive noses help us search for an astonishingly wide variety of things. In traditional search and detection methods dogs sniff the environment directly to search for prey, escaped felons, lost persons, explosives, contraband and rare plant and animal species. But now filter-search odor detection methods, also referred to as Remote Explosive Scent Tracing or REST, bring minefields to dogs instead of taking dogs to minefields.
In REST air samples are collected from minefields using vacuum pumps equipped with special filters. After the air samples pass through them the filters are protected so that they retain odorant molecules while they’re transported to a secure location for testing. Samples are collected under strict quality assurance and quality control protocols similar to those used in environmental investigation and monitoring programs.
While sample collection can be tedious and time-consuming, REST methods provide a relatively fast way to identify areas that are free of mines and they allow dogs and handlers to work away from the danger of mines. Detailed mine location methods then only need to be used in areas where evidence of mines has been detected.
… there are times when it is not practical to use dogs on the ground, as the tarmac at border posts gets too hot for them during the day, or if there could be a danger to the animal.
Now researchers at the South African company Mechem are adapting their Explosive and Drug Detection System to the fight against poachers.
Inspector T.C.Oosthuizen, of the South African Police Service, said: “When we work at Komatipoort for instance, the tarmac is so hot, it starts melting so you can’t get a dog to work from 12 o’clock in the afternoon.
“And the smugglers, they know about it, so then they know you can’t bring a dog to the border posts because the dog of course will burn.
“With this machine you take the samples, and give it to the dog in a controlled environment, an air-conditioned facility. It’s cool for the dog so the dog can work longer and more.”
Hot pavement may not be as dangerous as a minefield but if authorities can provide dogs and handlers with a safe and comfortable work environment they can work more hours and, we hope, identify more contraband.
Detailed information on REST and other mine detection methods was published in the Geneva International Centre for Humanitarian Demining’s (GICHD) Mine Detection Dogs: Training, Operations and Odour Detection in June of 2003. GICHD states that REST isn’t used to locate mines directly. It’s used to identify areas that don’t contain traces of explosives or other target scents so that detailed searches for mines don’t need to be conducted there. They’re sometimes referred to as “reduction methods” because they reduce the size of the area where dangerous and time-consuming mine locating work must be done.
Composite air samples are systematically collected across the minefield. Each sample contains the molecules that remain in a filter after the air passed through it when the sample was collected. The area over which each sample was collected is carefully recorded and this allows the perimeter of areas where scent was and was not detected to be identified.
REST methods allow a relatively small number of searchers and dogs to screen large areas quickly. GHCID reports that in mine work as much as 95% of target areas can be declared safe (or mine free) after REST screening. If similar results are obtained when searching for rhino horn, this means that detailed searches for horn only need to be conducted in a small percentage of vehicles and cargo passing through checkpoint areas.
REST methods are most efficient when the target is a rare and unusual odorant because if it is common or widespread all the sample filters would contain odorant and no areas can be eliminated. Rhino horn is rare and unusual, so the method applies well to these searches.
Because dogs don’t perform scent work perfectly, when clearing mine fields two or more dogs are used to check each composite sample. The samples are transported to a central location where they’re attached to stands that make it easy for the dogs to sniff them. The dogs are trained to sniff each filter and indicate a positive find by sitting or lying down next to filters where they smell traces of the target odorant. Once a dog has sniffed all of the filters individually, they’re moved to different locations in the stands and the same dog sniffs each one again. After each sample has been sniffed twice by the same dog, one or more additional dogs repeat the process with the same filters (or duplicate filters). If a filter is examined by each dog twice without any positive indications the area it was collected from is identified as being clear of the target odorant.
This kind of detailed duplicate analysis is probably not as important when searching for contraband instead of explosives. Even if each sample is checked twice by a single dog, authorities should be able to clear traffic through checkpoints much more quickly than they can with direct detection methods. And, as CNN notes, dogs can also search traffic at times and in places where it would not otherwise be safe for them to do so.
Rhinos are critically endangered and poaching is dramatically on the rise because of demand from Asian markets where horn goes for as much as $30,000 a pound. Just this week LiveScience reported that:
“Within South Africa’s national parks — not counting private land there, where poaching was rare — there were 10 rhinos poached in 2007,” said Matthew Lewis, senior program officer for African species conservation for the World Wildlife Fund. “Thus far in 2010 alone, more than 200 rhinos were poached within South Africa, with a lot of those poached outside national parks, so that’s a more than 2,000 percent increase in just three years’ time.”
Because the market has become so lucrative, organized groups of poachers now use high-tech equipment like helicopters, night-vision scopes, silencers and chemical immobilization to avoid detection and arrest.
I hope that REST helps authorities arrest more poachers in this deadly, and rapidly escalating, cat and mouse game before it’s too late…