Narcotics detection dogs are a type of police dog trained specifically to search for and indicate the presence of illicit drugs. Other types of detection dogs include explosive detection dogs who can detect both explosives and firearms, and cadaver dogs who sniff out the presence of blood and human remains. While it is possible to train a dog to detect both narcotics and explosives, it is often more effective to have a dog specialize in one specific category. Even within the specific realm of narcotics detection, there is variation in the ways that certain dogs can be trained. For example, the difference between a dog trained to indicate passively versus a dog trained to indicate aggressively is very important. Often, a dog that indicates aggressively will be able to pinpoint the precise location of narcotics more accurately. However, a passive indicator is ideal for situations where collateral damage, such as scratched paint or damaged seat-cushions, must be avoided.

Many myths exist concerning the ability to trick or fool detection dogs, all of which have been proven false. A dog’s sense of smell is estimated to be about 100,000 times as powerful as that of humans. The olfactory lobes in a dog’s brain are four times the size of that in humans, and with the size of a dog’s brain averaging at about one tenth the size of a human brain, the percentage of grey matter being devoted to the sense of smell is about forty times greater in canines than in humans. All manner of strongly-scented substances from coffee and spices to urine have been used to attempt to mask the smell of illicit drugs, and all have failed. A dog’s nose simply can’t be tricked. However, this does not mean that detection dogs are perfect. Training with a narcotics detection dog is an ongoing process, not because the dog forgets a scent, but to ensure that the dog does not begin to indicate on the wrong scents.

In the United States, all narcotics detection dogs are trained using real narcotics, obtained by the trainer through rigorous licensing and criminal record checks. However, some countries will not permit anyone to be in possession of illegal narcotics, even for the purposes of training detection dogs. In these places, the use of “pseudo drugs” to train detection dogs is common. A pseudo drug is a complex chemical substance that mimics the scent of real narcotics to a canine. How the dog interprets the scent to be the same as that of real narcotics is a mystery, as these substances often smell nothing like real narcotics to a human. However, they do seem to do the trick in places where real narcotics cannot be used for training.

The breeds of dog used for narcotics detection take into account both the olfactory precision of the breed, as well as loyalty and ability to be trained. While bloodhounds have a reputation as having the most precise noses, narcotics detection dogs tend to be German Shepherds, Belgian Malinois‘ and Labrador Retrievers for both their accurate noses and their intelligence and determination in training.