A wagging tail means a happy dog, right? Not always…Since dogs haven’t found a way yet to talk to their owners, they use other means to convey what they’re thinking. Body language, especially tail wagging, is one.

The Science

A study completed by Italian researchers of dogs observing videos of other dogs wagging their tails to the right or left intended to determine whether dogs effectively utilize tail wags to communicate with each other. When watching dogs wagging their tails to the right, the observing dogs would relax and sometimes even try to approach the other dog. Dogs observed wagging their tails to the left, however, resulted in heightened heart rates and anxiousness in those dogs watching the videos.

The study concluded that dogs, like people, have asymmetrically oriented brains. The activation of one side of the brain based on an emotional response, would cause the tail to wag toward the opposite direction. According to the researchers, the directional wagging is not intended to be communication, it’s simply a byproduct of that mechanism of asymmetry, but it can still be a good indicator of a dog’s emotional state.

Dog wagging its tailWhile these studies of dog behavior may be valid, it can be hard for pet owners to put them to practical use. Dogs are much better at interpreting other dog behavior than humans. Plus, the tail wagging can be quite subtle and would require humans to see the wagging in slow motion to really observe differences.

The Practice

Dog trainer and educator Penny Layne has six dogs of her own and had this to say about the tail wagging study: “I don’t dispute the research, but what I have is the experience of the last 22 years of studying dogs and training them and as a speaker and I’m reading more than just the tail. You really have to look for a while to see if the tail is going left or right. You can’t waste that much time if your life is threatened,” she says.

The best way to tell if a dog’s tail wag is negative or positive, according to many pet experts, is to watch its overall body language. Happy dogs are relaxed, hold their tails at a natural height, and aren’t showing signs of anxiety or aggression in the rest of their body language. Pay attention to how they’re holding their ears, if their lips are tight or loose, if their hair or hackles are raised, and if they are vocalizing in any way.

You may also want to keep in mind the type of dog you’re observing. Dogs naturally hold their tails at different heights depending on their breed. In general, a broad wag to the side is typically a sign of a happy dog, especially if the hips are wiggling with the tail. This is often accompanied by relaxed ears and a soft or smiling mouth.

What to Watch For

According to VetDepot’s blog, there are three tail wagging behaviors that signal trouble:

  • A slow, low wag. This can be a sign of insecurity. If a dog is feeling fearful, it’s tail may continue to wag even if it’s tucked between the legs. If you think your dog is feeling uneasy for any reason, be cautious about introducing a new person or animal.


  • A slow, high wag. This is often a display of dominance. Be cautious if your dog is exhibiting this behavior.


  • A wagging tail accompanied by barking. This is often a warning sign of aggression or over-excitement.

Your dog has many ways to communicate with you, his or her tail is just one of them. Now that you know what signs to look for pay attention to what your pup’s tail is telling you and the dogs around them! This may help both of you stay safe and happy when interacting with other dogs.