A wagging tail is often read as universal happiness — but the direction, height, and speed of the wag all carry different meanings.

Research has found that dogs wag more to the right when they feel positive emotions, and more to the left when feeling anxious or negative — a asymmetry linked to brain hemisphere activation.

A tail held high and stiff, wagging quickly, can actually signal alertness or agitation rather than joy — worth watching for around unfamiliar dogs.

A relaxed, loose wag at a neutral height is the clearest sign of genuine calm happiness.