Perhaps pack dogs don’t need curly tails because they have each other to keep warm, whereas the solitary dogs (pets) need them. Give me a gold star for trying? LOL
Dogs, all dogs, are essentially wolves. They have done DNA studies and found that wolf DNA is indistinguishable form that of a Chihuahua. Dogs and wolves can mate and produce viable offspring that is not sterile like a mule or other hybridized type of animal.
My Chihuahua still thinks she is a wolf..............