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Why do dogs wag their tails?

Dogs wag their tails when they feel happy, excited, or sometimes nervous.

A dog's tail is like a language that shows how it feels. People talk to share their feelings, but dogs use their tails instead. Wagging does not always mean happiness, so we need to look closely.

If a dog wags its tail in big, easy movements, it is usually happy. It wags like this when it sees its owner or plays with someone it loves. But if the tail wags fast and stiff, the dog might be excited or nervous.

Scientists have also studied which way a dog's tail wags. If the tail wags more to the right, the dog is usually happy. If it wags more to the left, the dog might feel a little worried or unsure. So it is not just whether the tail wags, but how it wags that matters.

Wolves, the ancestors of dogs, also used their tails to talk to each other. After dogs became pets, they kept doing this with people too.

Quick facts

  • Dogs use their tails to show their feelings.
  • Big, easy tail wags usually show happiness.
  • Fast, stiff tail wags can show excitement or nervousness.
  • If the tail wags more to the right, the dog is happy.
  • If the tail wags more to the left, the dog might feel unsure.
  • Wolves, the ancestors of dogs, also used their tails to talk to each other.

Check what you remember

3 questions — all of them come from the quick facts above. There is no score and no wrong turn.

1. Why do dogs wag their tails?

2. What animal are dogs descended from?

3. If a dog's tail wags more to the right, how might it be feeling?

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