Unlike people, in healthy dogs and puppies, the bones of the spine extend way beyond the pelvis to form a long straight tail. (thehappypuppysite.com)
We have dogs with straight tails, dogs with curled tails, and some dogs with tightly coiled tails (found in some Bulldogs for example) that have a tendency to grow into the dog (ouch). (thehappypuppysite.com)
However, their grey coats, non-blue eyes, and straight tails together create a strong wolflike appearance. (pethelpful.com)