From LiveScience.com:

Dog owners are used to coming home to ecstatic, tail-wagging pooches. Tail wagging is common in our canine companions, but did they pick it up just for us, or do wolves, their wild ancestors and modern-day relatives, also get their waggle on?

The short answer is that yes, wolves wag their tails. “Most of the time, you see them wag their tails with so-called greeting behavior,” Sarah Marshall-Pescini, a senior researcher at the domestication lab in the Konrad Lorenz Institute of Ethology at the University of Veterinary Medicine, Vienna in Austria, told Live Science. “Greeting behaviors are effectively behavior shown mostly by subordinate individuals towards dominant individuals, and particularly during reunions after separation.”

Click here for the full story.