I don't know if this will help but this weekend I was watching "Dogs with jobs". They featured a beautiful pit bull who was an amazing search and rescue dog. The lady who owned and worked with this dog said that pit bulls were exceptional for this kind of work because they don't tire, like the commonly thought of hound dogs. They showed a mock rescuse that took place over 8 or 9 hours and this dog kept going. Checking everything from abandoned houses to water canels, through the forest and through the city. They made quite a point out of really laughing at the "pit bull sterotype". They showed this unbeielvable caring and intelligent dog, doing an amazing job and people dramatically running away when they saw him, off leash.
Well if this didn't help your research it is an interesting story anyway I think!!!!!