Some days, your dog’s tail wags slow and low, and other days, it’s like the kraken, taking out everything in its path. And when it’s time to visit the vet, you may never see your dog’s tail at all, because it’s tucked tightly under their rear end. 

So what’s the story behind the crazy wags, slow wags, and no-wag days? Here’s the low-down on the highs and lows of why dogs wag their tails.

A lot of people think that dog tail wagging can only mean one thing: pure joy. It’s true that dogs wear their hearts on their tails. A wagging tail can be deciphered as happiness in many scenarios. 

But dog tail language might just be a little more complex than we think. A wagging tail can actually signify a few other states of mind as well. Here’s a secret decoder guide to your dog’s tail.

This is the easiest one to recognize: the happy tail. Your dog is probably around people they like, doing something they think is fun, whether it’s playing fetch or just licking your face. Their tail will be wagging free and loose at a good, steady speed. 

If their excitement level increases, their tail will wag faster and faster. It could even turn into a helicopter tail if your dog reaches maximum happiness. And then you’re in for a case of the body wiggles along with the out-of-control tail.

Just the idea of something that your dog sees as positive can get their tail wagging. This is a fun one that you can test out right now. Grab your dog’s favorite treat, making a bunch of noise that they’re sure to recognize, like the sound of the treat bag. Then let your dog see the treat, and have them sit and/or stay. You should already start to see their butt wiggling.

If your dog is not food motivated, you can grab something else, like their leash, if they get excited to go on a walk. But be sure to follow through and actually take them out if you reach for the leash!

If your dog is in a playful mood, they can communicate this with a wagging tail, too. They may bring you their favorite stuffie or ball to throw, whether they drop it at your feet or try to play keep away. 

This kind of wagging could happen when you first come home, or when you’re at the park, or just anytime your pup is ready to play. They may also have their butt high in the air, wagging their tail, with their front paws down low.

This probably seems like a weird reason for dogs to wag their tails. If it usually means that they are happy or playful, then why would they wag their tail when they are scared? 

You may see your dog doing this at the vet’s office–their tail will probably be tucked under their rear end, between their legs, and might be wagging slightly. It’s sort of like a gesture that’s meant to appease someone.

If a dog that you don’t know is doing this, it’s best not to try to calm them or interact with them, as fear can turn into aggression. 

Is your dog’s tail wagging low and slow? It could be a sign that they are being cautious about a new experience. Perhaps they are meeting a stranger or a new animal. 

They’re not sure whether they are in a safe situation where they can wag their tail happily or if they should be on the lookout for danger. So your pup will go for the low, slow wag just to be safe. You might notice that their body stance is a little stiff while they check everything out. 

Dogs can wag their tails if they are in an aggressive state. You may come across a dog you don’t know that has their tail straight up, or even arched over their back, that is also wagging their tail. Look for other clues, like a stiff body posture, flattened ears, staring, and/or growling. If you’re not sure, don’t approach, even if the dog’s tail is wagging.

If your own dog is doing this, you’ll probably have some idea as to what could be upsetting them. Be cautious and try to remove the stressor before things escalate.

Not only should you pay attention to how fast a dog’s tail wags, but also how high or low they hold it, and the direction they wag it in. All of these things help dogs communicate their intentions to people and other dogs–you just need to know how to read tail language! 

Tail Wagging Speed: Think of tail speed as intensity. The faster the wag, the more intense the emotion. So, if a happy dog is wagging their tail super fast, they are really, really happy. But if a dog is standing at attention, staring, and wagging their tail high over their back, it could be intense aggression. If a dog is wagging their tail and suddenly stops, it may mean that they are no longer happy with the situation, such as if they no longer want to be pet.

Tail Wagging Height: The higher the tail, the more confident a dog is feeling. A happy dog’s tail is held higher than usual, but beware when the tail is straight up, wagging or not. An uncertain dog’s tail will be held lower than usual, and if they’re frightened, they will even tuck it under their bottom and between their legs.

Tail Wagging Direction: Studies have shown that dogs wag their tails slightly to the right in response to something positive, and slightly to the left when they felt threatened. The research found that other dogs can pick up on these cues, too. When the dogs in the study saw a dog wagging their tail to the right, it made them more relaxed, but if they saw a dog wagging to the left, they tensed up and their heart rate increased.