A little over 50 years ago, an anonymous caller to Trans World Airlines (TWA) threatened to blow up several of its jets unless he received USD2 million. The authorities at New York’s JFK airport immediately grounded flights. Others were turned back, including Flight 7 which had been en route to Los Angeles. Then it was noted that Brandy was on the scene.
The German shepherd was at the airport that day to do a demonstration as part of an Army-funded research project. Now she was called on to go to work. She was led from one TWA aircraft to the next, and when she was taken on board the recently returned Flight 7 she went straight to a briefcase labelled ‘crew’. It was filled with C4 explosive.
That was a particularly spectacular save. Bombers, it seems, are disinclined to work where they know sniffer dogs—or detection dogs, as they’re more properly known—will be in operation. And, since 9/11 in particular, that can seem to be everywhere. Many will be familiar with the sight of dogs at gigs and festivals, on the hunt for illegal drugs. Before COVID-19 scuppered public gatherings, even Ascot—one of the most upscale events in the international sporting calendar—was due to deploy sniffer dogs for the first time this year.
But detection dogs are now being trained to sniff out the more unexpected too. If there are ‘bomb dogs’ there are also so-called ‘digital dogs’—aka ‘porn-sniffing dogs’—used to find hard drives and SIM cards used to share child pornography. There are the dogs trained to track tiger parts for the wildlife crime prevention organisation Traffic India, where, according to its head Dr Saket Badola, “the use of dogs is making a real dent in the problem because they’re taking the fight to areas where humans won’t readily venture [and] because they’re making it so difficult to trade animal parts [that] the poachers are giving up”.
Less arrestingly, but no less impressively, there are dogs now used to sniff out water leaks. Thames Water, which manages mains supply to London, recently trialled the use of dogs to find cracked or burst pipes, walking a 40km pipeline buried two metres below the countryside from which a trained dog can nonetheless detect the minute traces of chlorine released with any leak.
Since the company spends around GBP1 million a day trying to fix 200 leaks, any assistance in finding these faster will save a lot of money. It’s niche—there are perhaps fewer than a dozen dogs in the world trained for this—but even the detection of dry rot in the construction industry has become canine- enabled. A dog can smell what a surveyor cannot see.
“You can train a dog to find anything that has an odour and just because we don’t think something has an odour, doesn’t mean it doesn’t,” says Brent Hardy, one-time close protection officer turned managing director of detection dog training company Scentpro, who’s supplied dogs and their handlers to war zones and the police forces of Hong Kong and Singapore.
“Providing we can get hold of a sample, we can train a dog to trace it. It’s the well-established problems that cost a lot to solve, and that haven’t been easy to solve, that are shaping dog training now. Blown electric cables—they’re another one seeing detector dogs being used. But a blown cable is akin to explosives in terms of scent.”
A dog’s world is olfactory before it’s anything else. But how extremely well-calibrated a dog’s nose is for scent is nonetheless amazing. They don’t even have the most sensitive of noses in the animal kingdom; elephants, rats, jackals, all would leave most dogs standing in some scent Olympics.
But dogs are amenable, companionable, even portable and can still detect the equivalent of a teaspoon of sugar dissolved in two Olympic-sized swimming pools of water. If humans have six million scent receptors, dogs have 300 million. If five percent of human brain resources are assigned to smelling, 35 percent of a dog’s brain is.
Nature has done a fine design on that canine nose too: when air enters a dog’s nose, it’s split into two channels: one for breathing and one for smelling; when a dog exhales, the air exits through slits to the side of its nose, thus not interfering with analysis of incoming odours.
Dogs can move each nostril independently, like scent direction finders. What dogs also do that humans can’t is known as particulation.
“If you walked into a house where there was some baking going on, you’d detect the aroma of baking. If you had a really good sense of smell you might be able to specify, say, ‘lemon cake’,” explains Hardy. “A dog would walk in and identify lemons, caster sugar, butter, flour and so on.”
This means dogs can be trained to zero in on one particular ingredient, not anything cased in plastic, for example, but specifically TPPO, the chemical used in the plastic that encases SIM cards. It also means it’s next to impossible to mask a scent to a dog in the way that it is to a human. “You get drug dealers hiding cocaine in coffee shipments,” explains Hardy.
“That might confuse you or me. That won’t confuse a detection dog. In fact, the smugglers know it won’t work too. What they’re hoping is that it’s the handler who’s not on form, not the dog. That’s why training the trainer, particularly to trust the dog, is as important as training the dog itself.” But this doesn’t mean any dog is good for detection work. The considerations are many.
Bloodhounds, notoriously, will follow a scent to the end of the Earth; it’s why they’re used to track escapees. But they also tend to smell pretty bad, which is a factor when working in a more public setting. Likewise, although German shepherds are among the leaders of the pack when it comes to scent detection, their association with aggression—it’s why they’re used for guard and patrol duties, after all—also makes them unsuitable for all situations.
“You tend to need a dog that looks friendly if you’re working around people all day,” notes Hardy. So it’s sporting dogs you’ll see on duty most often: labradors, German shorthair pointers, vizslas, golden retrievers. Such dogs express the ideal balance of qualities: intelligence (but not too much), tractability, endurance and, perhaps most importantly of all, a certain obsessiveness.
“You know those dogs that you don’t want in the house all the time because they just never stop?” asks Hardy. “Those are the dogs we want, the ones that don’t understand there’s any such thing as rest. They’re naturally driven without having to be geed up. But they can also be given deep motivation to hunt for an object: food, their ball.”
It’s with this object that a certain odour—be that of explosives or heroin—is, to use the terminology of the trainers, imprinted through repetition. It’s proper Pavlov’s dog territory. The ‘hide’—the target object—is hidden among distractions and other deliberate miscues of ever greater complexity and, over time, the dog comes to associate the odour or odours with the positive reinforcement that is the reward of its favourite thing.
The dogs are given five or so generalised versions of the target odour—and, yes, detection dog trainers have to be licensed so as to be supplied with sufficient quantities of Semtex, or cocaine, or whatever illegal stuff they need to do their work—until it learns to hone in on its target odour.
You need a dog that’s really determined to find that odour too—they ‘commit to the odour’. Typically dogs are trained to then give not an active indication—a bark, for example, or mouthing or scrabbling at the target, which might be a very bad idea if it’s a bomb—but a passive indication. That means simply sitting next to the target. Or giving it a long, hard stare.
Some dogs need to really be on their toes. The International Search and Rescue Dog Organisation (IRO), a non-profit established after the 1988 Armenian earthquake to co-ordinate the use of dogs in search missions, has to be particularly picky. Not only do its dogs have to have the scent obsession, they also have to be able to work with the agility and obedience that allows them to take off on their own through a forest in search of their target or scrabble over rubble fields where their handlers can’t easily move.
But so-called ‘man-trailing’ is next level: that’s when a dog, without the many years of training typically required to learn focus on a specific odour, is given one individual’s scent cold and told to find him or her right off the bat. Walkers lost in the hills, children lost in the neighbourhood—dogs get a quick sniff and seek them out.
“We all have a generic human scent that these dogs can be trained to pursue. We all shed a scent over the ground, in the grass, when we pass over terrain,” says the IRO’s general secretary Andrea Thuma. “That works well in a disaster situation, when you’re trying to find anybody. But in some situations, dogs also have to be trained to ignore all of those cues in favour of one specific individual’s scent and perhaps to hone in on that through crowds of people. And that’s impressive.”
Remarkably, dogs are now even being used to scent targets within people—to find cancers, diabetes and other illnesses, or, as one Vancouver hospital has trialled, those pesky C. difficile antibiotic-resistant microbes.
If the training of detection dogs has, to date, been something akin to a craft, now it’s necessarily becoming a science, entailing blind and double-blind trials. One such ongoing study has shown that dogs can scent malaria in samples of socks worn by children infested with the malaria parasite. The result could be both a test in which diagnosis is considerably faster than blood sampling and lab work, and detection in people who are still asymptomatic, which can be crucial to curtailing transmission of infectious diseases.
“The amazing difference with this kind of work is that we can’t teach the dog the solution. We can teach a dog what marijuana smells like, but not what, say, cancer smells like,” explains Mark Doggett (“yes, that’s my surname, ironically,” he says), a dog trainer with Medical Detection Dogs, the leading organisation working with MIT and various medical bodies on a development programme backed by the Bill & Melinda Gates Foundation.
“We can give a dog urine samples and what follows is teamwork to assess whether there’s something suspicious in what is revealed or whether that should be ignored,” Doggett adds. “Yet it’s the dog that, over time, has to work out the common factor between those samples that indicate the illness. It’s incredible, really. Yet there are still sceptics regarding this kind of work, even within the medical world. Tell someone you have a machine that detects malaria and they accept that. Tell them that machine has a wet nose and a fluffy coat and you might see one running around the park and attitudes can change very quickly.”
But that does raise an important question. Surely by now technology has offered some kind of replacement for the nose of man’s best friend? Sniffer dogs are not cheap, after all. One might typically cost a few thousand dollars to buy and train, which can take up to three years, all for a working career of around seven years; that’s not counting the expense of training their handlers, who usually work in a dedicated team, one trainer to one dog.
Certainly there have been efforts to replace dogs with a machine but none, yet, can match the canine. Billions have so far been spent on trying to devise an electronic nose with the same sensitivity as that of a dog. Some have even come close: over the last decade one US Defense Department project developed a fluorescent polymer-based scent-detecting technology dubbed Fido X3, designed to be used alongside dogs rather than to replace them; Pacific Northwest National Laboratory now has a technology capable of indicating vapour levels at a dog- like few parts per trillion.
But a dog can learn to adapt. A dog can generalise regardless of the cancer type or the size of the tumour, and even detect cancers before they form a tumour. A machine is stuck in its programming. “And then you find that you can’t walk a machine around a stadium,” Doggett laughs. This said, detection dogs are not without practical problems themselves. A shift in the law—that sees most drugs remain illegal but perhaps one, like cannabis, legalised—can create all sorts of confusion.
In Canada and certain states in the US, for example, some have claimed that dogs have become redundant because if they sniff out heroin or meth, a case will likely be thrown out if cannabis is also present, thus leading courts to deem the arrest illegitimate. There have been arguments made too that the presence of sniffer dogs encourages casual drug users to take ever more drastic steps to hide their supply, to binge them or merely to use them ahead of going out—all of which might be moot if your stance is that such drugs are illegal and shouldn’t be used anyway.
Then there is the argument that the number of false positive hits—anywhere between 20 and 70 percent, depending on the target, the scenario and the sample—is too high to make sniffer dogs dependable, though dog trainers typically counter by saying this isn’t the dogs’ fault, so much as their handlers’.
“Sometimes it’s the dogs who are inexperienced. They learn over time from other detection dogs and actually get better the longer they’ve been on the job. But it’s always a challenge when a dog is paired with an inexperienced handler,” explains Joe Chopko, a training specialist with the National Dog Detection Training Center, which trains dogs for the US Department of Agriculture to prevent the illegal importation of certain virus- carrying pests, fruits and meats; yes, dogs are even able to set aside their own evolutionary-embedded love of a juicy piece of meat to single out those meat products that are not allowed.
“There’s a difference of course between a handler reading their dog and leading their dog, keeping in mind that dogs have been domesticated to pick up on incredibly subtle cues from humans. Dogs see everything and want to please. We have to work with that in mind.” But these seem minor stumbling blocks in what looks set to be the new beginnings of an already beautiful relationship, with better dog/human understanding likely to lead to only more snuffling and sniffing in the corners.
Certainly demand for detection dogs shows no limits. A couple of years ago, the American Kennel Club established a detection dog task force, charged with developing a stable source of trainee dogs for the US government’s ever-expanding needs; more recently, it launched its Patriotic Puppy Program to encourage breeders to set aside a dog from each litter, one that might be suitable for training.
“The need for detection dogs is enormous now,” reckons Sheila Goffe, the task force’s staff lead. “But we do need to have the right dogs. People say ‘why can’t you just get them from shelters?’. But you have to go through 100 dogs to find one you’d even consider right for training. And even then the wash- out rate is so high. The bottom line is that exceptional work requires an exceptional animal.”
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