A dog’s nose is a thing of wonder.

Whether sniffing around inside your home, tracking down some outdoor scent at the park, or salivating at the aroma of a dish cooking in your kitchen, a dog’s nose is always working. No matter what they are doing or where they are, dogs can’t help but use their most developed sense to complement the way they see and interpret the world around them.

It is for this reason that the world’s police forces have incorporated thousands of dogs into their ranks and trained them to catch, control, and, thanks to their fabulously powerful ability to smell, track crime suspects and fugitives of the law.

These police dogs, or K-9s as they are also known, have become an important part of pop culture, and you will hear many myths and half-truths that have grown around them.

Today I am going to set the record straight and answer some of the most common questions I’ve heard people ask about police dogs and their magical sense of smell.

How Long Can A Police Dog Track A Scent?

Most police dogs can track a scent for up to 2 weeks. The exact amount of time will vary depending on the type of breed and how much training the dog has received.

If conditions are right, some well-trained breeds may be able to detect and track smells months after the fact, other breeds won’t be able to pick up a scent trail after 24 hours, especially if they have not received proper training.

How Far Will A Police Dog Be Able To Track A Scent?

Some police dog breeds such as bloodhounds will be able to track a scent for over 100 miles. This is because bloodhounds have one of the most complex olfactory organs in the animal kingdom.

Other breeds, such as the English Bulldog will fare far worse because their sense of smell is relatively undeveloped when compared to common police dog breeds such as German Shepherds, Labrador Retrievers, and Bloodhounds.

How Sensitive Is A Police Dog’s Sense Of Smell?

Dogs have some of the most powerful olfactory organs in the animal kingdom. This means that for the most part, they can detect trace scents that remain hidden from humans.

How Sensitive Is A Police Dog’s Sense Of Smell?

With the added tracking and scent detection training given to police dogs, these wonderful creatures can detect scents with an extreme sensitivity that is orders of magnitude more powerful than a human’s.

For example, a police dog can detect microscopic traces of illicit drugs from dozens of feet away. They are also able to detect the scent of illicit drugs days after a person has come into contact with them.

Can A Police Dog Track A Scent In The Rain?

This is one of the marked weaknesses in the scent tracking capacity of a police dog. While heavy rain will not outright destroy a scent trail, it can disperse or dilute to the point that most dogs will have a hard time tracking it over long distances.

You see, a dog’s capacity to track a scent hinges on the complex physics of airborne particles. Dogs possess hundreds of millions of smell receptors inside their noses, and these receptors can detect tiny traces of microscopic scent particles that float freely through the air.

Can A Police Dog Track A Scent In The Rain?

When it rains, these scent particles get washed out of the air and this limits the animal’s capacity to dictate odor.

Since police dogs are extensively trained they may be able to detect scent trails in rain, but they will definitely have a harder time than normal.

Can Police Dogs Track The Scent Of Things Other Than Drugs?

Yes, they can. Police dogs can be trained to detect the scent of things other than drugs. They have the ability to detect contraband, corpses, human blood, and even cell phones.

However, police dogs are most commonly trained to detect the smell of a long list of controlled substances and illicit drugs. For example, a well-trained police dog is able to recognize and track the scent of popular drugs such as marijuana, cocaine, heroin, methamphetamines, a plethora of opioids and opiates, and various hallucinogens.

Specially trained dogs are trained to detect even more substances. For example, some private security firms train their dogs to detect legal drugs that are commonly abused and taken recreationally. These include things like Xanax and alcoholic beverages.