Difference between a bulldog and a catch dog...

ive had some good ones that were pound dogs or just showed up at co workers houses and ive bought some with papers that was scared of everything. i had a choclate bulldog one time that was the strangest bulldog ive ever been around he woudlnt wag his tail or lick you or any of that he had a glaze look in his eyes like he had been strung out for awhile lol . he wouldnt bark or any non sense, he was a good catch dog he was fast always on the ear and didnt pull and jerk after you got him off we caught alot of big hogs with him by himself and he serverd his purpose as good as any would have. i had another one that came from some dog fighters way up north of me my buddys give me after i lost my other one so id have a replacement, he didnt have any papers and was about like the other one i spoke of except he was a little more friendly and he never showed and signs of dog agression i would put him in the box with all my other dogs he was a good catch dog, the day he died he got gutted and had a string of guts dragging behind him stepping on them when i got there and caught the hog, i hand cuffed the hog and got him off but he never let go even walking on his own guts in a brair patch i dont think stuff like that comes from papers or any of that i think its just in some of them and some of them dont have the heart others do. its a difference in all bulldogs i think whethere they be from the pound or the rich man kennels but i think it depends on each individual dog.