Why your cat’s tail gets puffy every now and then?

Have you ever noticed that when something startles your cat, his tail becomes big and puffy? Usually, it may stay like this for several minutes, especially if the cat is frightened by a noise, but is not able to tell what was the source of it.

A startled cat wit ha puffy tail.
Photo by Jon Ross, cc

In addition to the puffy tail, the hair may be standing on your cat’s lower back. So, what is going on? Why your cat has got a puffy tail?

The reason is similar to why we, humans, get goosebumps. Goosebumps are small bumps on your skin that usually appear when you are cold or scared or even emotional. They make your skin look like that of a plucked goose, hence the name.

Standing hair makes your cat’s tail appear larger

The function of goosebumps is to make the hair stand. In a horrid situation, your body produces adrenaline, which then makes tiny muscles in our skin to contract and create a little bump at the follicle of every hair.

Erected hair, also called piloerection, serves several functions. For us, piloerection is just a remnant of our ancestors, since we have very little hair on our skin. Well, most of us have. However, for cats and other animals, piloerection is a big deal.

  • Foremost, standing hair makes the animal look larger. This is why it’s so useful in horrific situations. It’s beneficial to be large and scary if something threatens you. If you appear big and scary, you are more likely to scare the intruder away.
  • An additional benefit is that puffy hair makes better heat insulation. So it’s why goosebumps show up when it’s cold. Standing hair traps air between the hairs which works well to preserve heat, just like mineral wool or a sweater does.

But why the tail? If appearing larges is so useful, why doesn’t the hair all over the body of the cat stand up? There isn’t a clear answer, but likely it’s because sometimes it may be needed to play it safe. Cats use their tails for communication a lot, and in certain situations, it is a useful “flag” to display.

Puffy tail quite often appears on cases when a cat has been startled by something but had not yet identified the source of it. It makes sense for a tail to puff, because, if held high, it may be the first thing the intruder notices. Large tail, by default, means large animal.

While the intruder investigates the tail, the rest of the cat’s body will adjust, depending on the size of the intruder. Too large intruder means it’s safer to appear small and invisible.

Note that nothing of this happens intentionally. Your cat is not able to control movements of hair, similarly like we can’t do anything when our goosebumps appear. When a cat is afraid, his puffy tail will appear. No way out of it. If you suspect your cat gets scared too often, learn to calm a fearful cat here.