The tosa inu and the pit bull may look very different, but they have a shared heritage. Sadly, it’s a gladiatorial heritage: Both dogs have been used in the past for fighting. This shared heritage often draws comparisons between the two breeds, but it’s essential for any potential owner to understand that, fighting history aside, these are two very distinct breeds.
Size, Weight and Strength
The tosa inu is the larger of the two breeds, measuring as much as 24 inches tall at the shoulders and weighing almost 200 pounds. Males and females are similar in size and weight. Pit bulls are shorter and typically less than half the weight of the Japanese tosas, weighing in around 77 pounds. However, size alone does not paint a full picture. Tosas are rather gangly and ungainly when compared with the shorter, more compact pit bulls. In terms of raw strength and power, the pit bull, with his low center of gravity and high muscle density, may prove to be stronger and more athletic than his larger Asian counterpart.
Intelligence and Trainability
Tosas are relatively easygoing; they respond to the tone of their owners' voices. They will look to their owner for guidance. They are by no means slow-witted, but they do not possess particularly high levels of curiosity or inquisitiveness. They are happy to be told what to do and will gladly focus on a single task for a long time, such as guarding a perimeter or watching out for intruders. By contrast, pit bulls are keen learners, with genuine desire to please their owners. They are eager to learn and do well with physical and mental challenges. They thrive when given activities that challenge their inquisitive nature and athleticism.
Temperament and Character
Despite their size and history as fighting dogs, both the tosa and the pit bull are remarkably gentle and kind-natured. The tosa has more of a docile, patient demeanor, while the pit bull is more "clownish" and playful. Both are great with kids, showing tolerance and patience. Despite this, one should never leave a dog and child unsupervised, especially if that dog is large enough to knock over a child accidentally.
Health and Life Span
For such large dogs, the tosas' 10- to 12-year life spans are relatively long. Pit bulls live for a similar amount of time. Tosas, like many large, deep-chested breeds, are prone to bloat. Pit bulls are less prone to this condition but do suffer from hip dysplasia -- as do the tosas -- as well as from cataracts and congenital heart disease.