YOU NEED TO KNOW THIS.WHY DOGS WAG THEIR TAILS

Some have suggested that tail wagging is simply a physiological means of getting rid of surplus energy. P. Dwight Tapp, who's conducted research at the University of Toronto in the cognitive functions and brain structures of dogs, points out that wagging also spreads pheromones by causing the muscles around the anus to contract, pressing on glands that release a scent. This scent communicates information about sex, age, and social status to other dogs.