training your puppy

Why does my dog wag its tail?

Many people associate a dog wagging their tail with a sign that they are happy, but this isn’t completely true – it’s much more complex than this!

A dog’s tail can be thought of as a signpost that they use to display a range of emotions, not just to other dogs but to us humans too. It’s therefore important for us to be able to better understand the emotions that our beloved companion is trying to express to us, as this will help us understand their wants and needs better.

A dog wagging their tail can portray many emotions such as happiness, anxiety, excitement, submission and even that they feel threatened. Not only that but different breeds of dog will have different resting positions of their tail.

It’s thought that a dog wagging their tail is a subconscious activity, i.e., they don’t think about doing it, much like when we blink our eyes. It is an outward expression of the emotions that they are feeling inside.

Puppies aren’t born wagging their tails, however. It takes some time for them to learn what different wags mean and will take cues from other dogs as they grow.

So, what emotions correspond to which tail positions in dogs?

Happiness or excitement

A happy or excited dog will usually hold their tail up high in the air and wag it enthusiastically – often the faster they wag it, the happier they are. The rest of your dog’s body language will often give clues that point towards excitement; they will have a smile on their face, ears perked up and be in a playful stance.


An aggressive dog will often have a very stiff, straight tail that is held upwards. A lack of wagging or very slow deliberate wag is likely seen.

Anxiety or submission

An anxious, scared, or submissive dog will usually hold their tail down between their legs and wag it slowly here. They may cower or shiver and appear generally hunched over.

Research has also shown that a tail wagging to the right represents positive emotions and a tail wagging to the left represents negative emotions – and what’s even more fascinating is that other dogs can distinguish between the two.

A dog’s tail isn’t just for communication however, in fact this is more of a secondary function. The tail, in evolutionary terms, is mainly there for balance. A dog running at high speed or on an unsteady surface will use their tail as a sort of counterbalance, helping to prevent them from falling over. It’s also useful as a rudder when your dog goes swimming!

So, as you can see there are many reasons why a dog may wag their tail, and very subtle differences between them. It’s therefore important not assume that every dog wagging its tail is happy, as it could in fact mean the opposite.

Dr Alex Crow

Dr Alexander Crow is a RCVS licensed Veterinary Surgeon currently practicing at Buttercross Veterinary centre, a small animal accredited veterinary practice in Nottingham, United Kingdom. He earned his Bachelor of veterinary medicine degree at the Royal Veterinary College London. His special interests include neurology and soft tissue surgery and hopes to start his surgical certificate in the next year. When not working, he enjoys travelling to Europe, painting and staying fit.

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