i have lost track of the amount of bull/grey xs that make it look hard work or wont do them unless they have back up-yet ive seen the 21/23 tts whippet/grey/sal swim the river and drop them for fun-infact smash anything with teeth-my mate had a coll/whip/grey dog 22 tts that would also smash anything that wanted a fight-some of the best dogs with the biggest heart are the little uns imo.atb my bitch is 23tt with a heart of a lion and my uncles 72 and said the best dog on teeth hes seen was a 19tts lurcher he didnt know the breeding but said she was a demon