Why Do Dogs Wag Their Tails?
It isn't always a sign that they are happy. They could be expressing something else.
Why do dogs wag their tails? Despite what you would think, it is not always to show happiness.
Dogs have tails to keep their balance when making sharp turns while running or swimming. However, they also use them in order to communicate. The way a tail moves could indicate whether a dog is happy or sad, excited or agitated.
Why do dogs wag their tails? There are more reasons than you would think. It isn’t always a sign that they are happy. They could be expressing something else.
A wagging tail can convey happiness.
Since dogs are not able to speak to us in our language, they use their body language in order to communicate. They will move their ears, eyes, and tail in certain ways to get certain points across.
It is impossible to tell whether a dog wags their tail voluntarily or if it happens on its own, without them consciously thinking about it. Some people believe it is both, the same way we can organically smile and force smiles, depending on the situation.
When a dog wags their tail to the right (if you are facing the same way they are), it is experiencing happy emotions. This is usually accompanied by a playful bowing gesture or a few licks to your hand.
Generally, the faster a dog wags their tail, the happier they are (unless the tail is also vibrating which means the dog is about to fight or run) and the higher the tail, the more excited they are (unless the tail is stiff which means they are feeling dominant and ready for a fight).
A wagging tail can convey fear.
A wagging tail is not always a good sign, so it does not necessarily mean you should approach a dog. It might be a warning that you should keep your distance, so be careful.
If the dog is wagging their tail to the left (if you are facing the same way they are), it is experiencing negative emotions like nervousness and anxiety. Likewise, when a dog is wagging their tail low, it could mean they are worried or afraid.
A low slow wag could mean that they are nervous and unsure of a person or a situation.
Basically, the lower the tail, the more submissive and insecure the dog is feeling and the higher the tail, the more dominant and alert the dog is feeling. The best spot for the tail is right in the middle, because that means the dog is feeling relaxed. What you want to see is a broad wag.
A wagging tail can convey so many different things.
A dog will wag their tail for a million different reasons. It is hard to tell why they are wagging if you are unfamiliar with the dog — but if it is your own dog, then it won’t be long until you associate its tail movements with what they want.
A dog might wag their tail to beg for food.
A dog might wag their tail to say sorry after getting in trouble.
A dog might wag their tail to call a truce when playing with another dog.
A dog might wag their tail in relief that you came home.
A dog might wag their tail as an invitation for you to play with them.
A dog might even wag their tail to spread their natural scent from their anal glands in order to mark their territory.
It’s hard to tell why your dog is wagging their tail at first, but once you get to know them well enough, reading their body language will become second nature. 
