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Dog mom with dog wagging his tail at Bond Vet

Why Do Dogs Wag Their Tails and What Does It Really Mean?

A wagging tail often means a dog is happy. But that’s not the only possibility—and incorrectly interpreting a tail wag could lead to a bite from an aggressive pup.

Dogs use their tails to communicate a variety of emotions and intentions. If you’re wondering why dogs' tails wag, read on to learn more about how dogs communicate and what your furkid’s tail could be trying to tell you…

What Does It Mean When Dogs Wag Their Tails?

Often, a wagging tail does in fact mean a dog is happy. However, there are exceptions. A wagging tail might convey another emotion or message, such as aggression, excitement, anxiety, or insecurity. 

Interpreting a tail wag incorrectly could mean the difference between a friendly, sloppy kiss versus receiving a bite from an aggressive or fearful dog.

Learning a dog’s “language” can take knowledge and practice. But many pet parents learn to interpret messages from dogs by observing a combination of the dog’s tail position and movement, other body language signals, and context or situational clues.

How to Interpret Your Dog’s Body Language

Unlike human beings who use a combination of words and body language to communicate, dogs can’t communicate via spoken words. Instead, they rely more heavily on body language. 

This includes facial expressions, eye movements, ear position, showing the teeth, body posture, tail position and movement, and other cues. Canines also rely on scent signaling and sounds/vocalizations. 

Tail Positions and What They Mean

Speaking of “tail language” specifically, dog owners can deduce a lot by watching their furkid’s tail. Signaling cues include tail height, movement, direction, and tension.

In general, a tail held very high is consistent with confidence, excitation, or strong emotions, whereas a tail held low or tucked under the body indicates fear or uncertainty. 

Tension or stiffness in the tail could indicate tension in your dog’s mood, whereas a loose tail wag is consistent with a relaxed or content dog.

The speed at which a pup’s tail wags can also give a lot of information. The wag we’re probably most familiar with—the “happy dog wiggle” you see when you get home from work—is most consistent with a happy, friendly dog. But faster or slower tail movements could indicate different emotions, especially when combined with other signals.

Holding the tail up high may also allow other dogs to get a better whif of that dog’s scent, since it exposes the anal glands. On the other hand, holding the tail low covers those scent glands, which may be a dog’s attempt to hide themselves when they feel scared or threatened.

Here are some examples of how all these tail factors work together with other body cues to communicate how a dog is feeling…

  • A friendly, happy wag typically involves the tail held in a natural position or somewhat elevated. The wag may range from medium-speed to strong and fast. Side-to-side hip movement, or a “butt wiggle,” may be involved. The dog’s tail tension and body posture are likely relaxed or neutral.

  • A dog who is aggressive, overly excited, or anticipating a fight may hold their tail directly upright. Their wag may be very fast and stiff, almost like a rattlesnake tail movement (it may look like the tail is vibrating) rather than a full-swing tail wag.

  • A fearful or submissive dog may display the characteristic tail lowered and tucked between the legs, with no tail wagging at all. Or, they may do a small, slow wag compared to their usual happy tail.

  • A curious dog is likely to hold their tail in a neutral or horizontal position, with or without small wags. If something catches their attention or puts them on alert, they may raise their tail a bit higher.

  • A dog who is insecure, or who would prefer to avoid an interaction with a human or another dog, may only do a slight tail wag or avoid wagging their tail altogether.

Keep in mind that all of these signals may vary by breed or other factors. 

Some breeds naturally hold their tail higher or lower than others. And some have tails that curl, docked (shortened) tails, or other physical factors that impact their tail communication. Tail signals should be interpreted compared to what is normal for them, not what is normal for a breed with different tail characteristics.

Interestingly, at least one study found that dogs are more likely to wag their tail to the right of their midline when they experience positive emotions, and more in a left direction for negative emotions. Scientists theorize that the left side of the brain (which controls the right side of the body) is associated with positive emotions like love, whereas the right side of the brain (which controls the left side of the body) may be associated with more fearful or unpleasant emotions. 

The Mechanics of Dog Tail Wagging

It’s thought that dogs’ tails were originally used for balance. The tail could help them turn suddenly while running or aid in control while jumping, swimming, etc. Then, tails evolved to serve a communication purpose as well.

How Do Dogs Wag Their Tails?

Dogs’ tails are a continuation of their spinal column. They are also made up of skeletal muscle and tendons/ligaments. Unlike the smooth muscle of intestines and blood vessels, skeletal muscle is under voluntary control. So, it stands to reason that dogs have conscious control over their tail movements just like they do over their leg movements.

When Do Puppies Start Wagging Their Tails?

Puppies don’t wag their tails until they are about one month of age. For this reason, it’s likely that tail wagging is a learned behavior

At first, tail wagging may be used to signal to a puppy’s mother that they are hungry or to tell their littermates playtime has gotten too rough or they don’t want to play anymore.

As puppies get older, tail communication becomes more varied and nuanced.

Is Tail Wagging Intentional Or Involuntary?

Since tail movements are controlled by skeletal muscle and tail wagging is a learned behavior, the action is likely intentional. However, it’s possible that tail movements may be a combination of voluntary and involuntary (or at least “autopilot”) control.

This may be similar to when human beings learn to walk, use a fork, drive, etc. In the learning phase, these movements require concentrated effort. But with practice, most of us do these things subconsciously, without voluntarily telling our legs or hands to move. Perhaps tail movements are similar for dogs.

How Do Dogs with Docked Tails Communicate?

It’s certainly true that tail docking can limit a dog’s natural ability to use their tail for communication. Some experts note that these dogs may rely more on other communication methods (vocalization, ear position, body posture, etc.) or that they may be more cautious in social situations.

For all these reasons, many veterinarians recommend dog owners avoid tail docking unless there is a medical reason for the procedure.

Learning Your Dog’s Tail Lingo

While everything discussed here holds true for many dogs, our furkids are unique individuals with their own personalities. So, your pup’s individual communication methods may differ. 

Use these guidelines as a starting point. But observe your pooch to see what they do in various social situations. This will help you better read your pet’s moods and pick up on anything they may be trying to communicate to you.

And when facing a dog you’re not familiar with, it’s best to be on the safe side and ask their owner before interacting with them, to ensure the pup is friendly.

Any questions or concerns about your dog’s tail or behaviors? A telehealth appointment can help you determine what’s normal and when further attention is needed. Learn more or schedule an appointment here.


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