My dad was one that raised and hunted lots of foxhounds of various pedigrees. They never live long, they burn the candle at both ends, as they will pursue game for 48 hours nonstop and come home looking looking like death. A 7 year old hound is old beyond years, but they love the chase more than life. I have a feeling that the great sled dogs are similar.
Thanks for that perspective. I never thought of it that way.