Get

In Your Inbox

Dogster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Why Are Police Dogs Called K9? History & Facts

Share

belgian malinois K9 dog

The history of using canines for police and military work goes back to the Romans using Neapolitan Mastiffs on the battlefield as “dogs of war.” However, police dogs are now an integral part of law enforcement, taking on the duties that they outperform humans in. Canines originally became our guardians and livestock herders through the ages. But when required, they acted as police dogs to ensure law and order while assisting in apprehending those lawbreakers.

The term “K-9” is a homophone for the word “canine.” Its first formal but unofficial use was during World War II. Its popularity undoubtedly rose from its ease of use instead of spelling out the word.

Dogster divider_v3_NEW_MAY_24_

The Beginnings of Canine Training Units

Using dogs in police work is a no-brainer. They can smell and detect things better than we can. They can run faster than any human, with Greyhounds clocked at a blistering 45 mph. Canines are also better equipped, with the word “canine” meaning “pointed tooth.” Our early history with these animals is chock full of stories of dogs fighting alongside humans, but they found their way into law enforcement in the late 19th century.

The Belgians recognized the potential for using dogs in this capacity, with the first training facility opening in 1899 in Ghent, Belgium. They didn’t recruit the typical canines we think of for these roles. Instead, wolfhounds and sheepdogs stepped up to the plate. Their size was undoubtedly a point in their favor. It didn’t take long for others, including the NYPD, to learn about their potential.

The trainers used a unique approach. They taught the pups to associate uniformed police officers as friendly and anyone else as hostile. These dogs were the ultimate multitaskers, detecting and bringing down their quarry. Unfortunately, the dogs’ training backfired after many complaints and an accidental shooting. The NYPD disbanded the country’s first canine unit. Several other cities also tried and failed.

solder and k9 dog in the airport
Image Credit: sandyman, Shutterstock

Dogster divider_v2_NEW_MAY_24_

The Quartermaster War Dog Program

Police dogs didn’t go away despite the charges of being overly aggressive. Private agencies still used them during the early 20th century. The military also had canines. Law enforcement in London kept dogs as companions when doing their rounds. Germany opened a training facility in Greenheide in 1920, making the German Shepherd Dog their star pupil. Scotland Yard got into the act in 1938.

Then, World War II started. The military saw the potential for the trained canines and secured them for the war effort. An organization called “Dogs for Defense” teamed up with the American Kennel Club to encourage citizens to donate capable canines to join the Quartermaster Corps K-9 Corps. That’s where the police dogs came into their own, and where the first unofficial use of the term “K-9” appears.

The animals adapted well to their new roles after training with the US Armed Forces War Dog Program. More than 10,000 canines went on to serve all branches of the military in 15 War Dog platoons. In London, law enforcement used dogs in recovery missions to locate victims of the Blitz. The K-9 units’ service during the two world wars cemented their use in law enforcement.

The dogs performed several vital tasks, including the following:
  • Mine detection
  • Messengers
  • Sentry duty
  • Scouts

They would find similar duties stateside after the war. March 13, 1942, is the official founding of the US Army K-9 Corps.

Dogster divider_v1_NEW_MAY_24_

Resurrecting Canine Use in Law Enforcement

The London Metropolitan Police recruited dogs for their regular duties after the end of World War II. Similarly, the United States resurrected canine use in various capacities, including security details in department stores. These efforts stalled in some areas for the same reasons they failed earlier. However, proponents recognized the need to refine the training methods and capitalize on the dogs’ strengths.

Several cities began training programs, including Dearborn, MI, Portland, OR, and Los Angeles, CA. The Baltimore City (MD) Police Department was the most successful, thanks to the efforts of a veteran of the US Marine’s K-9 Corps. Presumably, the use of the term “K-9” segued into law enforcement because of the widespread attention Baltimore received. Other nearby cities began their own K-9 units.

A German shepherd lies at the feet of a military man outdoors
Image Credit: MAKSYM CHUB, Shutterstock

Dogster divider_v3_NEW_MAY_24_

Modern-Day Police Work

Modern-day police work has led to specialization with K-9 units. Law enforcement had previously used Bloodhounds for search and detection. That usage goes back hundreds of years. However, their tasks have evolved with the times and technology. Police dogs are typically single or dual-purpose animals. Jobs include detection or patrol.

The former involves tracking or finding explosives or narcotics. The canines only train with one type of detection. The latter works with security, clearances, and officer protection. Interestingly, one task resembles the role of guardian dogs, which historically would capture intruders and keep them at bay until the landowner or groundskeeper arrived. Today, we call it suspect apprehension.

The term “K-9” has stuck with law enforcement and the various organizations working with these animals, including the National Police Dog Foundation and the United States Police Canine Association (USPCA). They use multiple breeds in these roles.

Even the unlikely Labrador Retriever has found a spot on the police K-9 units. The London Metropolitan Police used them in the mid-1940s to accompany bobbies on patrol for purse snatchers in Hyde Park. The military continues to use dogs for various duties based on the unique talents of the breed. They have a permanent place alongside soldiers on and off the battlefield.

Man in military uniform with German shepherd dog outdoors
Image Credit: New Africa, Shutterstock

Dogster divider_v2_NEW_MAY_24_

Final Thoughts

While the formal history of police dogs started rocky, canines have proved themselves to be valuable companions for law enforcement and the military. They are courageous and loyal companions. Many personnel can thank their K-9 units for protecting them during difficult and dangerous times. That day when a wild canid first approached a human was the beginning of a beautiful friendship.


Featured Image Credit: Sashulity, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything dog

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Dogster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Ask Dr. Paola- Help! My Dog’s Sleeping Habits Have Changed! (May 18, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

The Crate Setup Most Dog Owners Get Wrong (And How To Fix It!)

Most people assume that if their dog hates the crate, the crate is the problem. So they try a bigger one, a different...

1,500 Beagles Rescued from Wisconsin Lab Farm – Here’s Where They’re Going

You may remember that a few weeks ago, we reported on a tense situation at Ridglan Farms, Wisconsin, a facility infamous for housing...

Dogster’s Weekly Photo Contest Winners: Window Watchers (May 11, 2026)

Every week our team gets the privilege of sorting through our readers photos to choose what dogs will win this weeks contest! See...

More related

Does a Maltese Shed a Lot? Vet-Verified Care and Grooming Tips

It’s easy to fall in love with the Maltese, with those bright eyes and gorgeous white hair, but there are other factors to...

Why Does My Dog’s Leg Give Out? 8 Vet-Reviewed Causes & What to Do

As a dog parent, we want our fur babies to stay fit and healthy forever, and it is sad and sometimes scary when...

9 Best Dog-Proof Trash Cans in 2026 – Reviews & Top Picks

A common challenge that many dog owners face is keeping dogs out of the trash, especially when it comes to kitchen trash cans...

Why Is My Dog’s Head Shaking Like a Seizure? Vet-Verified Facts & FAQ

If you’ve seen your dog’s head shaking like they’re having a seizure, it probably scared you a bit and caused you to ask...

Keep reading

Thanksgiving Food for Dogs: Safe Options & What to Avoid (Vet Verified)

Thanksgiving is an important holiday for many families and friends in various countries. Since we count our dogs as members of our families, it’s only natural that we want to include them on this special day. For most families, Thanksgiving...

family-with-dog-celebrating-thanksgiving

How to Cook Salmon for Dogs: Vet-Approved Recipes & What to Know

Most pet parents know salmon is a nutritious treat for their canine friends. However, some owners don’t know the best way to cook salmon for dogs. Salmon should never be offered raw to a dog since salmon poisoning can occur...

raw salmon meat on wooden board

Can Dogs Eat Pine Nuts? Vet-Verified Nutrition Facts & Considerations

There are many pieces of misinformation floating around the web on what is and is not safe for your canine companions. One of these very topics might have to do with pine nuts. Are pine nuts toxic to dogs? No,...

Dogster-Can-Dogs-Eat-Pine Nuts

Are Slow Feeders Good for Dogs? Vet-Reviewed Purpose & How to Use Them

Does your dog practically inhale their food? If so, you may want to consider a slow-feeder dog bowl. Slow-feeder bowls are designed to make food harder to get so that your dog has to pick around, gathering a kibble or...

Retriever dog holding a slow bowl in it's mouth in the kitchen

Can Dogs Eat Quinoa? Canine Diet & Health (Vet-Approved)

Quinoa is a gluten-free seed that has been a staple in many human diets for centuries, but has been elevated to prominence in recent years as a natural alternative to grains for health-conscious humans. It is also considered a healthy...

Can Dogs Eat_quinoa

10 Best Dog Foods in the UK in 2026 – Reviews & Top Picks

Gone are the days of limited dog food choices. As owners have become more attuned to canine nutritional requirements and have access to a wealth of information on ingredients, both good and bad, the range of dog food has expanded...

shih tzu dog getting wet food from owner at kitchen

What Does Pumpkin Do for Dogs? 7 Vet-Verified Health Benefits & Serving Tips

Pumpkin (Cucurbita spp) is readily available, inexpensive, and easy to prepare for your dog. It is also packed full of vitamins and minerals and is considered a superfood for our canine companions. That said, you do need to be careful...

slices of pumpkin

Can Dog Food Go Bad? Vet-Approved Facts & Tips to Preserve It

< Every dog owner has been in a situation where they buy bulk dog food to save money, trips to the grocery store, or time. Maybe you couldn’t power through that one open bag of dog food quite yet, or...

wet and dry dog food

Love Dogs? So Do We! Join the Dogster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Dogster Email Newsletter