my american staffy is very sweet and playful. I have three younger kids that he plays with. Besides them we also have 2 cats and a boston terrier. 99 percent of the time he is friendly with all but within the past year he has attacked the boston terrier a number of times which seems unprovoked and the ferocity of attacks has increased also to the point where i could only get him to let go by chocking him. He will just switch his attitude and kinda stalk before he attacks. Some of the times we have realized we caused it by play wrestling with my wife or kids or just start acting real excited, which makes him excited. so we cut that stuff out. He has been neutered years ago, we also dont really exercise him besides playing fetch in the back yard but nothing real active which we are going to change starting now. he is 3 and a half and i always wrestled with him to play, does that cause aggressive behavior to eventually come out? Is there any other ways to change the path he is on? how can we as owners change? i admit to yelling alot if my dogs or kids act up, could that be causing it too? Any suggestions? Also I have never seen an old pitbull, do they maintain their good attitudes all their life or do they get cranky like some other old dogs? any suggestions or critiques will be greatly appreciated, would like to change to keep the happy home.