A dogs posture, facial expression and tail movements can communicate a number of different messages to other dogs and to humans.
Friendly Dogs --- Relaxed ears in down position, flat tail with plenty of wagging and make eye contact without staring.
Submissive Dogs --- ears down, eyes averted and their tail between their legs. they may roll over on their backs or urinate while lying down.
Dominating Dogs --- Erect ears and tail, staring eyes and tend to put their paws on other dogs backs and may be pushy with their owner.
Truly Aggressive Dogs --- Stare and hold their tails motionless, growl and put their ears forward. (STAY SAFE)