Build me a heat tolerant dog

I agree to a point Scott....I do think phenotype is a good place to start tho,Chris if you are speaking of the two black dogs...conditioning is a big part but them two gyps are not only deep chested but long chested as well IMO I think that has alot to do with it. If you look historically at say some of the world champion beagles,they generally have a loner body than a typical AKC beagle...to me a better opotunity for oxenen exchange,same w/ big hounds,look at the lenghth of there chest as well as the depth. I have been watching my two pups I have been hunting,deep chest but short deep chests to me less lung capacity and I am sure some lack of conditioning on my part but if you noticed they do ware out a bit sooner than I would like.