I'm not talking about natural selection. How would a brachycephalic dog be a natural advantage? Try to make a brachycephalic bovine. So far, we have not found another organism with the fluid adaptability of the canid. I have been trying to relocate the article I read, but there is something to the genome of a canid which allows this rapid polymorphism, specifically a line of code. Also Belyaev's foxes were an interesting study.