Dogs in a Good Mood Wag Their Tails to the Right

A wagging tail does not always mean the same thing. Researchers studying canine behavior found that dogs tend to wag with a bias toward one side depending on their emotional state.

When dogs experience positive emotions, their tails tend to move more toward their right side. When they feel anxious, threatened or otherwise distressed, the wag tends to favor their left side. These directions are described from the dog’s perspective.

How other dogs respond

In experiments, dogs were shown images of other dogs wagging predominantly to the left or right while researchers monitored their behavior and heart rate.

• Left-biased wagging produced more anxious behavior and an increased heart rate.
• Right-biased wagging prompted a calmer response.

The findings indicate that dogs can perceive this asymmetry and react to the emotional information it conveys.

An automatic signal

The difference may arise from the way the brain’s two hemispheres process positive and negative experiences. Researchers believe the resulting tail movements are probably automatic rather than a deliberate form of sign language.

Tail direction should not be interpreted in isolation. A dog’s posture, facial expression, movement and surroundings all provide important context for understanding its mood.