Tosa Inu: Dog Breed Profile

Characteristics, History, Care Tips, and Helpful Information for Pet Owners

Tosa dog

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The Tosa, sometimes referred to as the Tosa Ken, Tosa Inu, or Japanese Mastiff, is a mastiff-type breed that was developed in Japan for dog fighting. Today, Tosas are still used in dog fighting in Japan, an activity which is legal. In most other parts of the world, where dog fighting is banned, the Tosa is a watchdog, guard dog, and companion. 

Though the Tosa Inu is a massive, powerful dog, it’s calm, quiet, and obedient. Tosas can be quietly affectionate with their own human families, but they are usually aloof with strangers. They are innately watchful and will alert you to anything deemed threatening or out of the ordinary. Tosas require extensive socialization to help them become accepting of welcome visitors. Although a Tosa might react aggressively toward a trespasser or a person threatening their home or family, they are not aggressive toward non-threatening humans. Tosas are gentle and tolerant with children who are part of the family and who are taught to interact with the dog respectfully.

Tosa dog

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Due to their dog-fighting history, Tosas can be aggressive toward other dogs, especially strange dogs. If raised together and socialized properly, Tosas might be able to live peacefully with other dogs that are members of the family. Keeping a pair of dogs of the opposite sex (one male and one female) is typically recommended, as they might be more likely to get along. Keeping Tosas with cats or other small pets is not generally advised.

Breed Overview

Group: Molossoid breeds, Mastiff type (FCI) 

Height: 21.5 to 23.5 inches tall at the shoulder

Weight: 100 to 200 pounds       

Coat: Short, hard, and dense

Color: Red, fawn, apricot, black, or brindle

Life Expectancy: 10 to 12 years

Characteristics of the Tosa Inu 

Affection Level Medium
Friendliness Low
Kid-Friendly Medium
Pet-Friendly Low
Exercise Needs Medium
Playfulness Low
Energy Level Medium
Trainability Medium
Intelligence Medium
Tendency to Bark Low
Amount of Shedding Low

History of the Tosa Inu

Dog fighting as a sport has a long history in Japan. The Tosa was purposefully created to be a bigger, stronger, more skilled fighting dog. Around the mid-19th century, Europeans introduced some of their prized fighting dogs to Japan. When Japanese dog fanciers saw the dogs’ prowess, they began introducing them into lines of fighting dogs in Japan. The breeds used to create the Tosa include another Japanese breed, the Shikoku, as well as Western breeds that had been newly introduced to Japan, including Bulldogs, Mastiffs, German Pointers, Great Danes, and possibly other breeds. 

The Tosa is not fully recognized by the American Kennel Club. However, it’s part of the AKC’s Foundation Stock Service, which is a stepping stone toward eventual full registration. In North America, the Tosa is recognized by the United Kennel Club. Internationally, the breed is recognized by the Fédération Cynologique Internationale (FCI). 

Tosa dog

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Tosa Inu Care

The Tosa’s short coat is simple to care for. The short, straight, dense coat lies tight to the body and needs no trimming. The coat sheds moderately. Brushing a few times a week can keep this under control. Trim the nails every two weeks and check inside the ears periodically. If the ears are dirty, clean them with a pet-safe ear cleaner and cotton balls or gauze squares. If you see redness or inflammation, have the dog examined by a veterinarian.

The Tosa is rather athletic for a giant breed. However, exercise requirements fall in the moderate range. The Tosa needs daily exercise and mental stimulation in the form of long walks, hikes, or chasing after a toy or ball in your safely enclosed yard. Due to the Tosa’s tendancy toward dog aggression, you should always keep your Tosa on a leash when out and about. 

Although the Tosa is intelligent and wants to please its owner, the breed is self-assured and can be willful. Use firm but fair training methods, including positive-reinforcement training and consistently enforcing the rules. Early, frequent socialization in puppyhood is absolutely vital to reduce overprotectiveness. 

Common Health Problems

Like all purebred dogs, the Tosa may be prone to developing certain genetically linked health conditions. Responsible breeders test their adult Tosa before to breeding them to ensure they don’t pass on undesirable health conditions, such as hip and elbow dysplasia. Like many large, deep-chested breeds, the Tosa may be at higher risk of developing gastric dilatation volvulus (often called bloat), a life-threatening condition where the stomach fills with air and twists on itself.  

Diet and Nutrition

Weighing in at 100 to 200 pounds, Tosa are massive. They eat a large volume of food, but it’s important to monitor just how much they are eating. This is especially important in puppyhood, as giant breeds need slow and steady growth to develop properly and avoid developing joint disorders like hip and elbow dysplasia. Excess weight, including obesity, can also lead to the development of other health conditions, like diabetes. More-active Tosas need more food; less-active Tosas need less. Feed measured meals twice a day to avoid weight gain. If you’re not sure what to feed or how much to feed your Tosa, ask your breeder or veterinarian for advice. 

Pros
  • Easy-care coat

  • Calm and docile with its owner


  • Excellent watch dog and guard dog

Cons
  • Dog- and animal-aggressive

  • Breed ownership is restricted in many countries

  • Requires abundant exercise, socialization, and training

Where to Adopt or Buy a Tosa Inu

Before embarking in Tosa ownership, check your country’s laws. Due to its dog-fighting background, owning a Tosa is banned outright or legally restricted in certain countries, including Australia, the United Kingdom, New Zealand, Norway, Denmark, and others. Some states, cities, local governments, landlords, and insurance companies also exclude the Tosa. In Japan, the breed is used for dog fighting, but in other parts of the world the Tosa is bred to be a show dog and companion. The breed is rare, so it might be hard to find a breeder. Be prepared to get on a waiting list for a puppy. One place to check for a Tosa breeder is the website of the American Kennel Club, which maintains a list of breeders for all breeds, including those like the Tosa that are not yet fully recognized, but are part of the AKC’s Foundation Stock Service.

More Dog Breeds and Further Research

If you like the Tosa, you might also like these breeds: 

Otherwise, check out all of our other dog breed articles to help you find the perfect dog for you and your family.