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Tosa inu dog

Breed overview

  • Breed group — Foundation Stock Service (American Kennel Club), Guardian Dog Group (United Kennel Club)
  • Height — 21.5-23.5 inches
  • Weight — 100-200 pounds
  • Coat length & texture — Short, smooth, and straight
  • Coat color — Red, fawn, black, or brindle
  • Exercise needs — High
  • Intelligence — High
  • Barking — When necessary
  • Life span — 10-12 years
  • Temperament — Calm, courageous, patient, and obedient
  • Hypoallergenic — No
  • Origin — Japan

Tosa inu fun facts 

👉 Coming up with a pet name can be fun but tricky. Search no further! According to PetScreening’s 2024 database, the majority of our users name their male Tosa Inus Yoda and Scrappy. Meanwhile, most of our users with female Tosa Inus love Bella, then Lucy.

  • The Tosa inu is sometimes called the “sumo wrestler of the dog world.” This nickname is attributed to their origins in Japan and their history as revered fighting dogs, much like sumo wrestlers in Japanese culture.
  • Tosa inus can vary significantly in size depending on their region. While the Japanese variety tends to be around 80-135 pounds, Western-bred Tosas can weigh anywhere from 130-200 lbs, due to selective breeding.
  • The breed is considered a national treasure in Japan. Despite its outdated dog fighting origins, the modern Tosa inu is celebrated for its loyalty and dignity, holding a special place in Japan’s cultural heritage.
Tosa inu dog being measured at a dog show

Tosa inu temperament and characteristics 

If you are an experienced owner looking for a giant dog breed, the Tosa inu may be the right dog for you. When properly trained and socialized as pets, this rare breed has a calm and reserved temperament, reflecting its noble lineage in Japan. While they exhibit patience and can be quite affectionate with their families, they’re not excessively playful. Their dignified demeanor often contrasts with their size, resulting in a gentle giant in many cases.

When it comes to children, the Tosa inu can be gentle and protective if raised alongside them. However, due to their size and strength, supervision is a must during interactions. Their relationship with cats or other animals can be variable. Some Tosas might get along peacefully with smaller animals, while others might exhibit a higher prey drive.

Tosa inu dogs are naturally wary of strangers, which can make them excellent watchdogs. They might be reserved or aloof with visitors initially but aren’t typically aggressive without reason. You can count on this dog breed to alert you of any intruders in your home.

Ideally, the breed thrives in homes with ample space and a securely fenced yard, though they can adjust to apartment living if given sufficient exercise. While Tosas do appreciate companionship, they aren’t overly demanding of attention.

Common Tosa inu health problems 

The Tosa inu is a large dog that generally has a good health outlook. However, like many bigger dog breeds, they can be susceptible to certain health conditions. Regular vet check-ups are vital for early detection and management.

  • Hip dysplasia. Hip dysplasia is a hereditary condition where the thigh bone doesn’t fit snugly enough into the hip joint. This leads to potential pain and arthritis.
  • Gastric dilatation and volvulus (GDV). GDV, also known as bloat, is a life-threatening condition where the stomach twists on itself, disrupting blood flow. Rapid intervention is essential, with emergency surgery required.
  • Entropion. Entropion is a canine eye condition where the eyelid rolls inward, causing irritation. Signs include frequent squinting and tearing excessively. It may require surgical correction.
  • Cardiac issues. Like many large breeds, Tosas can be prone to heart conditions which need monitoring and early treatment for the best prognosis. One of the more common heart failure diseases in dogs is dilated cardiomyopathy, which is when the heart muscle weakens and the heart then becomes enlarged.

Cost of caring for a Tosa inu

Caring for a Tosa inu, or any dog breed, involves significant financial responsibility. Aside from the basics like food and toys, pet parents also need to consider the costs of health problems.

Hip dysplasia treatments, for instance, might include surgery, physical therapy, and lifelong medications. Bloat, if it requires surgical intervention, can result in steep veterinary bills, and conditions like entropion or cardiac issues also carry their own set of treatment costs.

Given the potential for high veterinary expenses, many Tosa inu owners find peace of mind in investing in pet health insurance, especially when done early in the pet’s life. Insurance can significantly reduce out-of-pocket expenses, ensuring that the dog receives the best care experience without a heavy financial burden.

However, not all pet owners might find insurance appealing or feasible. In this case, creating a dedicated pet budget or opening a pet savings account can be beneficial. This proactive approach ensures that there’s a financial safety net in place, reducing stress when unplanned veterinary expenses arise.

History of the Tosa inu

The Tosa inu, often simply called the Tosa, and also known as the Tosa ken, Japanese mastiff, or Japanese fighting dog, is a breed of dog that originates from the Tosa province (now called Kochi) on the island of Shikoku in Japan. This Shikoku breed was developed in the late 19th century by crossing native Japanese dogs with several Western breeds like the mastiff, St. Bernard, Great Dane, and the bull terrier. The primary goal was to create a resilient and powerful dog breed for dog fighting, which was a popular sport in the region.

Although dog fighting is now illegal and controversial in many places, including the United States, the Tosa’s history is still honored by dog fighters in some Japanese jurisdictions where the practice is conducted under strict rules. In the U.S., Tosa breeders strive to keep these dogs out of the wrong hands and make sure pups go to proper prospective pet owners.

Tosa inu mother with her puppies

Caring for your Tosa inu

Looking after a new puppy, regardless of the breed, can be a daunting task. Your initial visit to the vet and organizing your Tosa inu’s vaccination schedule are the first two essential steps. Additionally, you need to get your home puppy-proofed and prepare for the teething phase.

While it’s unsettling to imagine your new pup getting lost, FidoAlert offers a complimentary Fido ID and tag to ensure you’re prepared for such scenarios. Below are some other fundamentals tailored for the Tosa inu.


The Tosa inu requires daily exercise to maintain its physical and mental well-being. On average, this breed needs about 45 minutes to an hour of daily exercise. This can include brisk walks, play sessions in a fenced yard, or even games that cater to its inherent strength and stamina.

It’s essential to modify exercise routines throughout the year for your Tosa, taking into account the breed’s sensitivity to extreme temperatures. Tosa inus have a short coat which doesn’t offer much protection against intense cold. In winter months, shorter outdoor sessions or indoor activities might be better to prevent your pup from getting too cold.

Similarly, during peak summer heat, it’s advisable to exercise your Tosa inu during the cooler early morning or late evening hours to prevent overheating.

Tosa inu running in a field


The Tosa inu has a short, dense, and sleek coat that’s relatively low-maintenance compared to longer-haired breeds.

When grooming your Tosa inu, occasional brushing, about once a week, is usually enough to remove loose hair and keep the coat healthy. Using a firm bristle brush or rubber grooming mitt can help in capturing the shed hair and distributing the skin’s natural oils, giving the coat a healthy sheen.

Additionally, like all breeds, a Tosa inu pup requires routine nail trimming. Their ears should be checked weekly and cleaned as needed to prevent wax build-up and potential infections. Lastly, regular teeth brushing or dental chews can help in maintaining oral health.

Diet and nutrition

Given its large size and muscular build, the Tosa inu has specific nutritional needs to ensure optimal health. While they don’t have breed-specific dietary requirements, they do benefit from high-quality dog food formulated for large breeds. Such formulations are designed to support joint health, muscle maintenance, and controlled growth, particularly during the puppy stage.

It’s crucial to monitor the Tosa inu’s calorie intake and weight since large breeds can be prone to obesity if overfed. The exact amount they should eat daily varies based on age, metabolism, activity level, and health. As a general guideline, adult Tosa inus may consume around three to five cups of quality dry dog food each day, divided into two meals.

However, this is a ballpark estimate, and intake may vary based on the dog . Pet parents are reminded always to refer to their veterinarian for precise food portioning tailored to their individual dog’s needs. Regular check-ins with the vet also ensure that the diet meets the dog’s changing requirements throughout its life.

Training your Tosa inu

The Tosa Inu is an intelligent breed with a strong-willed nature, making them trainable but requiring consistent firm leadership. Due to their history as fighting dogs, they can be dominant and stubborn, so training should commence at an early age to clearly instill proper puppy behaviors and obedience.

Positive reinforcement techniques, such as treats, praises, and play, work best for the Inu. Harsh training methods or negative feedback can be counterproductive and might hinder the training process. Consistency is key, as it’s essential for this Japanese breed to understand boundaries and expectations.

The modern Tosa is a patient dog breed overall. However, because of their strength and size, obedience training is especially crucial to ensure they are manageable and safe long term. Group training classes can also be beneficial, especially for inexperienced dog owners.

Professional help provides both instruction and socialization opportunities, which goes hand in hand with your dog’s loyalty. Engaging them in activities that challenge their intellect and body, like agility or obedience competitions, can further harness the capabilities of this breed.

Tosa inu puppy

Breeds similar to the Tosa inu

Not sure if the Tosa inu is the perfect fit? There are other breeds with similarities in size, appearance, or temperament that might appeal to you. Here’s a glimpse at a few:

  • Mastiff. An ancient breed known for its immense size and gentle nature. Despite their intimidating appearance, mastiff breeds are affectionate, loyal, and good with families. You might also look into Tibetan mastiffs if you want a slightly smaller (but still large) build.
  • Bullmastiff. A combination of agility and strength, bull mastiffs are natural protectors and guard dogs. They are reliable and have a calm demeanor, making them good family dogs when properly trained and socialized.
  • Great Dane. The Great Dane is a majestic and towering breed. It is often referred to as the “gentle giant”, just like the Tosa inu. Great Danes are large dogs with a gentle and affectionate nature that is great for families.

Frequently asked questions

Are Tosa inus good with young children?

With proper socialization and training, Tosas can be gentle with children, but due to their size and strength, supervision is always recommended.

Is the Tosa inu aggressive?

While they were originally bred as fighting dogs, with the right training and early socialization, most Tosa inus are completely calm and loyal. However, they can be wary of strangers.

Can I have a Tosa inu in an apartment?

Yes, many dog parents have large breeds in apartments. Given adequate exercise, they can adapt to apartment living, but they do appreciate having space to move around.