From a purely hypothetical viewpoint, to explore the limits of canine smell, is it possible to mask the smell of illicit goods with a strong smelling substance such as coffee?
Following this line of thought, a strong-smelling substance such as coffee beans or ground coffee would be a good starting point. After all, we humans can enjoy the smell of coffee, so the scent, to a dog's sophisticated nose, must be pretty overpowering. But is it overwhelming enough to hide another weaker scent?
The answer is no! Dogs can, indeed, smell through coffee because they build up a scent profile. Much like the top, middle, and bottom notes of a perfume, a dog can distinguish a range of smells, separating them from one, more dominant smell.
Signs a Dog Can Smell Through Coffee
Dogs are super-sensitive scenting machines. They are the full ticket when it comes to tracking and finding objects using their nose; Not only can they pick up a faint odor some distance away, but they can track and pinpoint it. To do this they have different ways of smelling.
When at a distance from the target, the dog moves rapidly in a sweeping, side-to-side motion. The dog takes lots of shallow sniffs, which sample the air and detect where the smell is strongest. They hone in on the scent by moving the head from side-to-side to stay on target.
Once they locate the likely origin of the smell, the dog slows right down. Now it's down for some fine detective work to read the signals. This requires a different pattern of sniffing, such that the dog takes slower deeper breaths to savor the air.
Reading the odor in this way, the dog picks up messages about how fresh the scent is, who left it, and other markers such as if a natural scent was left by a male or female. In the world of dogs and territory marking, this hugely detailed information is like the dog reading a poster about who just passed by.
- Tail up
- Zig-zagging from side to side
- Less frequent, deep sniffs
- Frequent shallow sniffs
- Head low to the ground
A History of Sniffer-Detection Dogs
One of the key skills dogs had to offer was the ability to follow a scent and track. From early man, who hunted to stay alive, through to the Middle Ages and aristocrats hunting for fun, a dog with a good nose was a valuable asset.
For centuries, the ability of dogs to follow a scent was accepted and used, but this was mainly for tracking prey. The seed of change came in the mid 20th century when in the 1940s, the American Armed Forces trained dogs to sniff out unexploded landmines in North Africa. These dogs saved many human lives. The hitherto untapped potential of the canine nose to detect other objects became apparent and was soon put to use.
The 1960s and 1970s saw the rise of the detection dog. These highly trained canines could detect illegal drugs, smuggled currency, and even illicit food substances.
From there, the role of the detection dog expanded still further. In the modern day, they are used to find people trapped under rubble, sniff out fire accelerants, detect explosives and much, much more.
The Science of a Dog's Sense of Smell
Following the analogy with sight, a dog reads a smell in a similar way to how we see things. Take a stew as an example. We can look at a stew and see lumps of steak, carrots, peas, potato, and gravy. A dog's sense of smell can 'see' the individual odors within a scent and pick each one out, in the same way, we see the ingredients in stew.
The dog achieves this tremendous feat by having a moist, wet nose (which traps scent molecules), billions of scent receptors in the nasal chamber, and a huge scent processing center in the brain. All of this adds up to an awesome scent processing capability that is able to distinguish other smells that lie beneath the dominant smell of coffee.
Training a Dog to Detect Odors Through Coffee
To successfully train a dog to pick up the scent of a specific substance, the dog needs to have a good sense of smell (some breeds are better than others) and a willingness to work for a reward, such as a game of tug.
Training starts with the handler engaging the dog in an energetic game of tug with a freshly laundered towel. This towel is free from odors and is the equivalent of a blank (scent) canvas. The dog is rewarded for playing tug and this is repeated on several occasions.
Next, the towel is impregnated with the scent of the substance you want to be detected. The dog engages again in games of tug and is rewarded.
Now, the dog is given a choice between the impregnated towel and a second, clean one. If the dog chooses the clean towel, their request to play tug is ignored. If they choose the scented towel, the handler reacts with enthusiasm, plays tug, and rewards the dog.
The next step is to introduce several towels, of which only one is scented. Again, the dog gets a reward for picking the correct one. When the dog is reliably doing this, then the handler places the towel out of sight. They encourage the dog to find the towel using their sense of smell.
Using this system of ignoring incorrect choice and rewarding the correct decision, the dog learns to seek out objects that smell of the substance they are trained to detect. It doesn't matter if the substance is hidden in coffee, as they will detect the smell over and above the coffee.
How to React to a Detection Dog:
A detection dog has a job to do and should never be interrupted whilst working. Always speak to the handler first, and check if it's OK to interupt the dog.