Why Do Dogs Wag Their Tails?

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You are out one day, visiting a dog park with your dear and beloved pet. They are wagging their tail and, by all appearances, having a wonderful time playing with another dog.

You are relaxing in the shade of a tree when seemingly out of the blue, you see your usually placid – or at least kind – dog snap at their new friend’s muzzle; not just playing, but actively trying to defend themselves in a move that is undeniably aggressive.

You jump up and move to separate the two dogs, but you have to wonder: your dog was wagging their tail. Doesn’t that mean she was having a good time? If so, how can you explain this unusual behavior?

why do dogs wag their tails

If not just to indicate happiness, then why do dogs wag their tails?

Television and movies have taught us that this action means they’re in a good mood. This is not always the case, however.

Wondering why dogs wag their tails is wondering just how dogs choose to communicate. It is more complicated than we imagine!

We will explore the different kinds of body language your dog displays in order for you to better understand how to respond and keep them from uncomfortable situations.

Why Do Dogs Wag Their Tails?


As we said, the most common understanding of a dog’s tail wagging is that it indicates happiness or relaxation.

When you are petting your dog on a warm, summer day, and you see their tail wagging, it is heartwarming; it means that you make them as happy as they make you.

Dogs that appear in film and on television frequently have had their tails CGI’d because the doggy actors were wagging their tails too much.

Since their training makes them comfortable on sets of all types, for them, acting as though they are growling at another actor is all a part of a game.


Sometimes, however, your dog will wag their tail when they are scared.

Think again to the example of the dog in the park; your pet may have been wagging their tail, but what were they doing with the rest of their body? Was their head down towards the ground?

Though their tail was wagging, were they bringing it between their legs? Were they bearing their neck?

If so, then they were submitting to the other dog present and indicating to you that they were uncomfortable, even scared, in the other dog’s presence.

Excited or Alert

When your dog catches sight of something interesting, their hunting instincts will likely kick in, despite hundreds of years of domestication.

This is another stimulus which may get their tail wagging; they will be alert, and their whole body will show it.

why does my dog wag their tail

When your dog’s tail is stuck straight up in the air and wagging, they are excited and ready to pounce or play with something that has caught their eye, or perhaps a friend who is standing nearby.

This tail wagging, upright stance can be happy or fierce, depending on circumstance.

If your dog is growling at the same time they are wagging their tail, the thing that has caught their eye is probably in for some trouble.

If instead, they lower the front of their body and stick the whole of their hindquarters in the air, they are looking to play.

How to Use the Warning Signs

Overall, a dog’s body language can be complicated, but it is easier to understand so long as you pay attention.

Dogs, just like people, display their stress, tension, fear, or relaxation in the way they hold themselves.


Short barks are the same as the shortness in tone you might display when you get frustrated.

While you might not shy away from someone who intimidates you, the tension you hold in your shoulders or in your neck is the same your dog may hold when confronted with an animal or situation that makes them uncomfortable.


So, let’s go back to the dog park. Your dog is playing with another dog, and you believe that all is well; their tail is wagging, so it must be.

why do dogs wag their tail

However, you notice out of the corner of your eye that they are crouching low to the ground.

Their ears, usually upright on their head, are pulled back, and whenever their new friend play-lunges towards them, they back away and try to make themselves small.

Your Response

You, having studied your dog’s body language, understand that they are afraid, and move in before they can snap at the other dog.

After you have taken them away from the stimulus that is scaring them and have calmed them down, you can feed them treats and offer as many pats as they require in order to feel comfortable in this environment once more.

Here’s a video going into a little more detail on why dogs wag their tail.

Overall Verdict

So, why do dogs wag their tails? To communicate.

What is important is that the humans around are paying attention to what is being said.

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