How do they do that?
To say that dogs have strong olfactory abilities is like saying the Pacific Ocean is kinda big. The inside of noses- both human and dog- are covered in millions of tiny receptor sites that capture scent molecules. On the inside of the human schnoz there are approximately 6 million of these receptor sites. Impressive, right? Well consider that sheepdogs have over 200 million of those receptor sites in their noses. Beagles have over 300 million of these receptor sites. Alexandra Horowitz’s book Inside of a Dog gives a great comparison to put a dog’s scent ability in perspective: “We might notice if our coffee’s been sweetened with a teaspoon of sugar; a dog can detect a teaspoon of sugar diluted in a million gallons of water: two Olympic-sized pools full.”
So how do dogs sniff out bed bugs? Bed bugs give off a combination of pheromones, which in large quantities can even be picked up by our mere 6 million nasal receptors. I’ve heard the smell described as everything from “sweet” or “like raspberries” to the very descriptive yet oddly correct “buggy smell”. While we can typically only notice the smell when they are in large quantities or recently disturbed and therefore giving off their alarm pheromone, a dog’s acute sense of smell allow them to detect much smaller numbers of bugs, sometimes even a single bug.
Bed bug scent detection dogs are trained in the same manner, and sometimes the same places, where drug, bomb and arson dogs are trained. They are given a target odor (in this case live bed bugs instead of narcotics or accelerants) and trained to react to that odor. Pestec’s, and most other bed bug dogs, will sit and then use their nose to point to the source of the smell.
What to look for when hiring a Bed Bug Sniffing Dog
One of the biggest questions people ask when trying to learn more about canine scent detection is, “How accurate are the dogs at finding bed bugs?” The problem is, I can’t give an exact percent. Only a few studies have been done on accuracy, and they generally don’t match up. I’ve heard numbers range from 47% to 98% accuracy. Scent detection ability and accuracy is affected based upon where and how the dog was trained, how often and intensive daily training occurs, the timing of the handler, if the handler verifies alerts, the mood and level of distractions for the dog, the mood and focus of the handler, and the movement of air in the room. So there’s really no way to give a direct number, but there are things you can ask that will ensure you’re getting the best team possible.
The National Pest Management Association has a set of training standards that outline levels of performance. These standards test the dog against distractions as well as live vs. dead evidence. Ideally, teams should be tested and certified through an outside, third party. When looking for a K9 scent detection team, always ask about their certifications.
Handlers should always verify any alerts that dogs have. At a bare minimum, a K9 handler should try to physically find the live bed bug if the dog alerts, even better if they’re doing a hand and/or visual inspection as well as a K9 inspection. Dogs are living creatures, and therefore capable of making mistakes. A false alert can be from anything from mistaking a smell, an unintended cue from a trainer, or an attempt for food, among other possibilities. By verifying the alert, the handler not only insures that the customer isn’t falsely diagnosed with a problem, but they are able to correct the dog’s training for the future. Hand and visual inspection of the bed area also allows the trainer to find any evidence, in the less common case of false-negatives, or look for evidence of other causes if bed bugs aren’t found.
I was speaking with a woman yesterday who was concerned about hiring a bed bug detection service from a pest management company because she believed they have a vested interest in finding bed bugs. This is not the first time I’ve heard this from a potential customer, and I don’t necessarily believe that it’s true. Integrated Pest Management companies practice least toxic solutions, and therefore aren’t spraying large amounts of chemicals that may kill anything that’s biting you. IPM techniques are a combination of identification, removal and prevention of pests. If a person is getting bites, the actual source of the problem needs to identified in order to treat it. Treating the wrong pest with targeted methods is a waste of time and money. Handlers that work for pest management companies often come with the benefit of being licensed pest control technicians, like being licensed Field Representatives by the California Structural Pest Control Board, which allows them to identify what could be the potential bite source if bed bugs aren’t found.
Another very common concern that I get, especially when doing K9 inspections in multi-unit buildings, is how can you be sure that the dog and handler aren’t actually spreading bed bugs. ACK! This is one of my least favorites because it’s very, very unlikely but the idea can still sometimes spread like 7th grade gossip. A big part of why this one isn’t true has less to do with the inspection and more to do with the bugs themselves. Bed bugs are nocturnal and don’t fly or jump. Generally, bed bugs are nocturnal and stay hidden until the ideal time when they can sense that their prey (us) are asleep. By waiting for optimum levels of CO2 and heat emissions, they are less likely to get smashed and killed while trying to feed. Typically a K9 handler is going to be coming through during the day when the bed bugs are more likely to be hiding. Even when disturbed, they’re going to try to go further into hiding, rather than heading towards food sources. Generally K9 handlers are also good about making sure they don’t brush up against anything in a possibly infected unit and inspecting themselves before they leave if they do. Just because they work with bed bugs doesn’t mean they want to bring them back to their homes.
Dogs are great tools for finding bed bugs, they’re powerful, accurate when properly trained, a lot more efficient than human inspections alone and really stinking cute. Now if you excuse me, I’m going to go give my favorite co-workers some belly rubs.
Brittany is a licensed pest management professional.