Detection Dogs: How do they do it?

When walking through an airport you might have seen a dog walking along side a police officer or airport official. Or, if you’re like me, you’ve seen dogs sniff out drugs and weapons on true-crime TV shows. While these canines play an important role in ensuring public safety, it’s a bit of a mystery trying to figure out how they do it.

How can detection dogs smell so well?

Dogs noses have, on average, 100 million to 300 million olfactory receptors, whereas humans only have approximately 6 million. They also have a unique organ called Jacobson’s organ that allows dogs to sniff out chemical changes that humans cannot. Because of their superior smelling ability, dogs are able to sniff out many different things, including drugs, weapons, human remains, and explosives. These canines are called “detection dogs.”

How are detection dogs trained?

There are multiple ways to train a detection dog to sniff out narcotics or weapons. But because dogs naturally use their noses to navigate the world since birth, the most important aspect of detection training is exercising that sense. K9 trainers might use an unscented towel as a play toy repeatedly, so the dog becomes accustomed to seeking it out. Then, the handler will wrap narcotics or weapon residue of some sort inside the blanket to get the dog to associate the drugs with the toy that they seek. Once the dog finds the toy with the substance(s) inside, the handler will reward the dog with a treat and begin hiding the towel in harder-to-find places. The dog will begin to associate finding the smell of the substances with getting a reward, making them seek it out even more.

But what parts of each dangerous substance are dogs smelling anyways?


Dogs can smell chemical residues of gunpowder and oils on firearms after the weapon has been fired or handled. When a human touches a gun, they leave oils with their smell on them, which detection dogs can track. Even unused guns are able to smelled and tracked by trained detection dogs. These dogs can be commonly found at large event spaces such as stadiums, or in schools and Federal buildings. Though they may be cute, it’s important to never interfere with any working dog.


Trained detection dogs can sniff out up to thirteen different illicit substances such as meth, heroin, marijuana, MDMA, cocaine, and opioids. Their superior sniffers can smell chemical compounds found in drugs that humans can’t and, through thorough training, can learn to point these out to their handlers.


Cadaver dogs have the gory but necessary job of finding human remains. They are able to track via trailing (smelling scents along the ground) and air-scenting (tracking and leading their handlers to the smell of decomposing bodies via smells in the air). These dogs frequently work on missing persons cases alongside search and rescue dogs. The training process of cadaver dogs begins with training the dogs to find an artificially-made chemical scent that micks the smell of dead bodies. Then, trainers will use real human remains to complete their training. While this process is gruesome, it’s important to remember how important this work is for gathering evidence for legal proceedings or bringing closure to victims’ families in murder cases.

Risks and Results

While detection dogs have an important job in keeping communities safe, it’s not without risks to their own safety. Depending on what each detection dog is searching for, they run the risk of coming into contact with deadly narcotics and biohazards, as well as being exposed to the elements, potential weapon injuries, and infection-causing bacteria. Essentially, being a detection dog is no easy task. But because this lifestyle is so drastically different from an average dog’s, what happens when these dogs stop working?

Nowadays, retired detection dogs can be adopted by their handlers or another family and live out the rest of their days in a loving home. But this wasn’t always the case. Prior to the enactment of Robby’s Law in 2000, most detection dogs were euthanized after their service ended.


Detection dogs serve a huge role in public safety, sometimes even putting their own lives at risk. From birth, they are trained to pick up on the microscopic details humans can only dream of sensing. From there, they work hard to make their communities better places. So, if you see a detection dog at work, be sure to appreciate all their efforts to keep you and your family safe.

Abigail Kurten
Author: Abigail Kurten

Hi! My name's Abigail, and I intern as a Content Writer for I have one dog, a chocolate lab named Riley who's the best! My favorite breed of dog is a Bulldog or Saint Bernard, though.

Leave a Comment