My pit mix was animal-aggressive. We did our best to socialize her, taking her to obedience classes and walks around the neighborhood. Didn't help. She was very maternal and got on fine with puppies, and with our other dogs whom she met as pups. I think with more work she could have been better socialized, but we did what we could as two working people. I could add that she spent her first six months with less responsible owners, but I'm 100% positive they never trained her to be aggressive.

That said, she was the most gentle and sweet animal you could imagine, around humans of any age. Loved babies, children and adults, never so much as growled at a human.

A couple of times she did get into fights - either because she escaped, before we learned what an escape artist she was - or because she was approached by an unleashed dog that wouldn't back down from her growling. The best way to break up a fight, we learned, was to simply put your hand in her mouth and pull her off the other animal. We might (and did) get bitten by the other dog, but never by the pit mix. Human flesh = no bite, simple as that.

I've read that both traits - animal aggressivity and an extreme aversion to hurting humans - were bred into pits. From my limited experience, I think that's credible.