What dog is tougher a pitbull or a American bull dog?

This is an ignorant question and leads me to believe that you plan on "using" this dog for less-than-scrupulous motives.

As with any animal, no dog is inherently "mean" or "nice" simply due to breeding. It's all about how the animal was trainedor raised. If they were abused or taught to fight, they will likely be mean and dangerous. This is a common misconception about pit bulls.

Just as with human children, dogs learn as they are taught, and behave according to their environment. A well-trained, loved, and well-handled puppy will become a good-natured, affectionate, well-behaved adult dog.