If your dog has a stiff tail with only the tip moving, it can signal aggressiveness or unrest. If your dog puts their whole body into wagging their tails, they're probably happy or excited.

and tail tip. This animal's long slender body, like that of a weasel, enables it to crawl in and out of the holes and dwellings of its primary prey—the prairie dog. Though black-footed ferrets ...

Dr. Warner advises looking out for blood spatters on walls or furniture, raw or split skin on the tip of your dog’s tail, or a slight reluctance to wag. Early intervention can stop the condition ...