Well take a look at it from a human aspect. You take someone that was born and raised in canada they would probably die if they stepped out of a building down here right now. Good head scratcher for sure.
Guess if anybody wants to prove it viable. The next litter of winter pups I have. I will throw them in the oven for some desert training. Lol

Dude, gotta disagree with that statement lol. My husband was born and raised in Saskatchewan till he was around 20, then moved down here. He handles the heat better than I do and I was raised in Texas heat.
I will not go for the smack. But I would say there are exceptions. But in general I would say where you are born rather than the time of year makes a bigger difference. Is is never cold down here except last winter.
But I think bidy build has more to do with heat tollerence than anything. Tall skinny handles heat better and shorter thicker handles cold better. Just look at the native people in any area before fast transportation and a/c. The population in Houston exploded with the a/c being put in houses. I know I have added a few punds and my heat tollerance has dropped. I used to work all day in the 100 degree heat with just water. I would die now. I think it is the extra lbs. I plan to lose it but just so I can hunt more

Skinny hunting dogs needed down here.