Why Do Cats Puff Up Their Tails?

Why Do Cats Puff Up Their Tails?

Have you noticed how your cat’s tail gets all puffy when she is caught by surprise or when she sees an unfamiliar dog? Cats tend to display their emotions using their tails. Read on for some interesting facts about why cats puff up their tails.

Why Do Cats Puff Up Their Tails?

Your cat is feeling playful. 

Cats’ tails fluff up and double in size due to piloerection. This is a phenomenon that causes the hairs to raise on the shoulders, back and tail. This is also seen in dogs, birds, rats and other animals. It is involuntary and due to the nervous system. 

Piloerection causes the hair to straighten away from the body, while adrenaline causes the muscles to contract. This is comparable to the goosebumps experienced by humans. 

When felines play, their tails become puffy and curl like a question mark. Some cats may shake their tail like a rattle, which may well be the equivalent of giggling.  

Aside from puffy tails, your cat may also exhibit erect ears, which means she is interested, but not threatened by what is going on.  Their whiskers will also point forward and they may wiggle their tails and pounce like predators when playing with other cats.

Your cat is angry and ready to attack. 

When cats are angry they make themselves bigger by puffing up their tails to make themselves look bigger. Along with an ear-splitting screech, this display of aggression could startle their enemies and give cats time to escape. Some owners could also see a ridge of fur standing up like a razor along their cat’s spine. 

Your cat is scared. 

Startled cats will also puff out their tails, arch their backs and flatten their ears. They may also growl or spit. Such spooked cats are sometimes referred to as Halloween cats. Less fearful cats go straight into attack mode, puffing their tails as a direct warning. Most cats, however, will settle for an aggressive bluff rather than a full-on attack. If their methods of intimidation don’t work, they won’t hesitate to use their claws. 

Other causes of piloerection among cats and other animals include insecurity, arousal, aggression, cold temperatures, defensiveness, to retain body heat, and when meeting new people or animals. 

What does it mean when a cat’s tail stands straight up?

When a cat’s tail stands straight up it means they are feeling confident and ready to approach in a friendly manner. This is an indication of a friendly greeting and is also how kittens greet their mothers. According to Cameron-Beaumont’s research in 1997, cats were willing to approach a cat-shaped shadow if they saw that it had a raised tail, but were reluctant to approach if the silhouette had a lowered tail.

If your cat approaches you with its tail straight up, it is a good time to pet them or play with them. 

What does it mean if your cat’s tail is held low to the ground?

Cats may lower their tails to the ground if they are frightened or anxious. If your cat’s tail is tucked between its legs, this means its is scared or may be feeling pain.

Why do cats wag their tails?

Cats wag their tails for the following reasons:

  • They are feeling confident. 
  • They feel scared. 
  • They are annoyed. 
  • They are excited. 
  • They are hunting. 
  • They feel secure. 

Why does my cat’s tail go up when I pet her?

Your cat’s tail goes up when you pet her because she approves of what you are doing. It may also mean she is happy to see you. But, be wary if the tail has a straight-up posture with a hook at the tip, as this could mean she is undecided about how she feels about your gesture. 


Cats express their emotions mostly through vocalization and body language, the latter including their tails. They puff up their tails when they are in the mood to play, but also when they are angry and ready to attack, or if they are startled or fearful. The phenomenon of puffing or fluffing the tail is called piloerection, an involuntary action whereby cats experience raised hairs on their shoulders, backs and tails.

Image: istockphoto.com / fotodrobik