Why Does A Cat’s Tail Puff Out?

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  • The cat’s tail is an amazing part of the anatomy. It has several functions including helping the cat to balance as well as communicating his mood. Different positions can tell you a lot about your cat’s current mood, including a puffy tail.

    Common causes

    • An upright quivering tail means he is happy.
    • Firmly tucked in between the legs means he’s submissive.
    • Upright means he’s friendly.
    • If the cat is sitting and his tail is flicking, he’s agitated.
    • If the cat’s tail is horizontal he’s relaxed.

    How does a cat’s tail puff up?

    When your cat’s tail puffs up, it’s experiencing a phenomenon called piloerection, a common response in many animals including humans.

    When your cat experiences stress or their fight or flight reaction is triggered, their nervous system releases specific hormone signals. These signals cause the muscles of your cat’s tail to contract, lifting the hair away from their skin. In some cases, this cascade of muscle contractions also reaches your cat’s back as well, lifting that hair as well.

    A similar reaction happens in humans when we experience goosebumps. Our hormone signals cause our muscles to contract and lift the hairs on our limbs. Because we have much less hair than our feline friends, the reaction looks more like bumps along our arms and legs.

    So, what does it mean when my cat puffs up his tail?

    You may have seen your cat get a fright and his tail gets puffy so that it resembled a bottle brush? He is feeling:

    • threatened,
    • defensive or
    • excited.

    The purpose of the tail actually puffing out like that is to give the impression that he is bigger than he really is. You may notice the hair running along the spine may also stand up at the same time. He wants to show that he is as big and as scary as possible.

    cat with puffy tail

    I don’t necessarily think that the puffy tail is always a sign of fear or defensiveness, however. I have also seen my own cats excitedly running around, stalking a killer piece of fluff or toy mouse, jumping, pouncing and the tail is all puffy.

    There is no fear, they do appear to be enacting stalking/hunting behavior, which leads me to assume that the puffed-up tail may also occur when a cat is hunting. Kittens are especially likely to puff up their tail during hunting/stalking games. I will have to get back to you on that one! I personally think it is a sign of excitement.

    Basically, any time your cat is feeling an extreme emotion, be it fear, anger, or excitement, he may puff up his tail.

    What to do when your cat puffs its tail

    What you should do for your cat will depend on why their tail is puffing in the first place.

    If your cat has just been startled by a sudden noise or movement, you can give your cat some time and space to calm down, and their tail will naturally deflate.

    If your cat is scared or stressed by something and you can identify the cause, look for ways that you can de-escalate the situation. This may mean closing the curtains if your cat has spotted a neighbor’s cat or removing your dog from the room if that’s causing their stress.

    If this is recurring behavior for your cat, consider adding more cat furniture to the room. Having more space to hide or climb can help your cat relieve stress, and it’s a great way to mitigate disagreements between multiple pets in your household.

    Frequently asked questions 

    Do long-haired cats puff up their tail?

    Just like short-haired cats, your long-haired cat can also experience piloerection, but it may be more difficult to tell. While the muscles in their tail may still contract because of their natural hormone response, long-haired cats have denser, often heavier fur.

    The weight of their fur can keep their fur from being fully pushed straight up. 

    Is there a way to determine why my cat’s tail puffed up?

    Your cat’s tail can puff up for many reasons, and you can determine the reason by using context clues. Look at your cat’s other body language and what situation they’re in.

    If your cat’s puffed tail is accompanied by pointed, alert ears, a flicking motion of their tail, and a crouched stance, your cat is probably feeling playful.

    However, if their tail is puffed, but tall and rigid and their pupils are dilated, your cat may be feeling scared or defensive towards something near them.

    From there, you can assess the situation to figure out what’s causing that specific emotion in your cat. 

    Are there any signs I should look for?

    In addition to a puffed tail, look to your cat’s tail for signs that they’re feeling threatened, aggressive, or scared. If your cat’s puffy tail is straight up and rigid, this can be a sign that they’re defensive and ready to attack.

    In contrast, a low, tucked tail can mean your cat is afraid of something nearby.

    Your cat’s ear direction can also give hints at your cat’s true feelings. If your cat’s ears are pushed back, that’s another sign that they’re feeling aggressive.


    • Julia Wilson, 'Cat World' Founder

      Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio