Think a dog’s tail wag is always an indication of happiness? Think again! Recent research suggests that tail wagging is a complex form of canine communication and can mean many different things.

A tail’s height and style of movement can be good indicators of a dog’s mood. Did you know that a tail held vertically indicates dominance, and a tail held in a lower position indicates submissiveness?

The movement of a tail wag can say a lot. Here’s a quick rundown:

• A slight wag is a shy, tentative greeting.
• A broad, wide wag is friendly and happy.
• A slow wag with a lowered tail can mean insecurity.
• A small, fast wag means that the dog may be about to run or fight.

New research adds a third level of meaning to the tail wag. An Italian study shows that a tail wagging towards the right is positive, while a tail wagging towards the left can be an indicator of negative feelings.

When dogs were shown their owners, their tails wagged strongly to the right. They wagged less vigorously to the right when they saw unfamiliar humans and cats. Tail wags towards the left were most common when dogs saw aggressive, unfamiliar dogs.

Experts theorize that this illustrates left brain/right brain differences. In humans and other animals, the left brain is associated with positive feelings and the right brain controls feelings associated with fear and sadness. Because each side of the brain controls opposite sides of the body, the tail wagging differences become clear.

Next time you say hello to your favorite dog, check out that tail!  An understanding of canine body language can improve human/dog interactions.

For more information, see Dr. Stanley Coren’s excellent article in Psychology Today.