Dog tail wagging is only one of the many ways that dogs communicate with humans. While it may seem like a natural behavior for a dog to wag his tail, the action itself definitely has some meaning and merit. The more difficult aspect of the equation can be trying to figure out what a dog means by wagging his tail.
Dog tail wagging originates from a dog's ancestors, when they used their tails and ears to communicate with each other. Now that most dogs are domesticated and only have cause to communicate with humans, the innate behavior still lives on and humans have to try to decode the habit.
Dog Tail Wagging and Social Communication
Most owners are somewhat awed when they notice that a new litter of puppies does not come out with wagging tails. The reason for this is that there is very little social interaction at such a young age. Because tail wagging is mostly a means of social communication between other animals and humans, puppies have very little use for this behavior until they become old enough to communicate.
Dog Tail Wagging and Posture
The posture, stance and position of a dog's tail can speak volumes about what he is trying to communicate. Posture and stance in combination with tail position is one of the better ways to try to determine what the wag of the tail means. When a dog is in a playful mood and ready to pounce, he will crouch down and his tail will wag erratically back and forth. This is his command that he is ready to play.
When a dog's posture is resolute and alert and the tail stays in a middle and stationary position, it indicates that a dog is aware or alert of something. This type of behavior usually signals that a dog will need to inspect whatever has piqued his curiosity, to determine if the situation is friendly or dangerous.
Dog Tail Wagging and Aggression
Tail wagging may almost always seem as though it is a sign of friendliness, but this is simply not the case. The position in which a dog holds his tail is equally as important as the movement of his tail.
When a dog holds his tail high in the air and the movement of the tail is not quick, but rather slow and deliberate, it can indicate that a dog is in an aggressive stance and feels the need to fight or defend.
If a dog is holding his tail high, but it is wagging his tail erratically back and forth, it indicates that he is in a jolly and friendly mood and welcomes human companionship. Most of the time, this type of behavior will be seen by an owner when he has come home after being away for awhile and his dog is happy to see him.
Submissive Dog Tail Wagging
When a dog is feeling submissive or afraid, whether from another animal or after being reprimanded, he will tuck his tail low between his legs and the movement of the tail will be very slight. This display of communication by a dog is simply meant as a means of submission to something greater than himself. It can also signal his desire to hide and back down from his fear.