What do dogs primarily use their tails for besides communication?

The story behind the answer

Balance is the key nonverbal job of a dog’s tail. Like a tightrope walker’s pole, it acts as a counterweight when a dog sprints, makes sharp turns, brakes suddenly, or lands from a jump. This “living rudder” stabilizes the spine and helps keep the center of mass over the feet—especially useful for agile breeds, herders, and canines navigating uneven ground.

Other options play smaller roles: