Why Do Cats Curl Into Balls When Sleeping? A Veterinarian Explains

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Cat curled up into a ball while sleeping.

Cats are well known for their ability to look comfortable wherever they sleep, and they can have some strange sleeping positions! Often though, most cats will simply curl up into a ball to snooze the hours away. But is there more to this common cat napping position, other than it’s just comfortable? Let’s take a closer look at why cats curl into balls when sleeping.

Quick Overview


Curling up into a ball is a common cat sleeping position.


Cats curl into tight balls when they sleep feel safer, stay warm, and feel comfortable.


Changes in your cat’s sleeping habits, such as different positions, or sleeping more or less than previously, could indicate an illness.

1. It’s Warm

Curling into a ball before a cat takes a nap is a way of ensuring they stay warm while they’re asleep. Cats are well known for seeking out warm spots to snooze the day away, such as a patch of sunlight, a comfy lap, or even on your computer!

The reason for this is that they have a higher core body temperature than we humans do, meaning that they need to work a bit harder to keep themselves warm.

Curling up into a ball while they sleep is a way for cats to conserve body heat and keep warm. In the wild, this is a necessity for survival and is a way to protect themselves from the elements.

For our domesticated cats, who often have the luxury of sleeping in a centrally heated home, it’s more of a way to keep themselves cozy while they nap. A cat’s soft thick fur provides an additional layer of insulation when they curl themselves up into a ball.

You might notice that when a cat lies out by the fire, or in a patch of sunlight, they’re often stretched out while they snooze. This is because there’s no need to conserve their body heat when there’s an alternative heat source available.

2. It’s Safe

Sleep is an essential part of life, but cats are at their most vulnerable when they’re asleep. In the wild, they would be vulnerable to attack by predators because they are not at the ready to defend themselves. Curling up into a ball while asleep protects a cat’s vulnerable areas such as the face and the vital organs in the chest and abdomen.

A cat’s tummy is a very sensitive area, which is why cats usually don’t enjoy having their stomach touched or stroked. When a cat is curled up into a ball, the stomach area is completely surrounded by the rest of the body, protecting it from harm.

Although a cat’s back and tail are exposed in this position, they are not as vulnerable as the other parts of a cat’s body that are protected within the curled-up ball.

3. It’s Comfortable

Lactulose use for cats.

Sleeping in a curled up ball is a comfortable position for cats.

Have you ever looked at your cat curled up in a ball of fluff and wished you could be that comfy when you sleep? One of the main reasons that your cat sleeps curled up in a ball is simply that it’s a very comfortable and comforting position to fall asleep in.

On average, cats spend between 15 to 20 hours out of each 24-hour period asleep! If you spent that much time sleeping, you’d want to be as comfortable as possible, too! Just like humans, cats have preferred sleeping positions and some cats will sleep curled up much more than others will.

4. It’s Practical

When cats curl up into a ball, their body is smaller and more compact, which allows them to fit into spaces that they otherwise wouldn’t be able to fit into. We all know how cats can find comfort and sleep in the strangest of places. Curling up into a ball to sleep is just one way that they can achieve this. Cat beds are often round, which will encourage your cat to sleep curled up.

What if My Cat No Longer Curls up Into a Ball When Sleeping?

If you have noticed that your cat doesn’t curl up into a ball when they are sleeping but they used to, then it might be a sign that this position is no longer comfortable. One of the most common reasons for this is arthritis, particularly in older cats.

You might also notice that your cat is less inclined to jump up onto surfaces, or is walking more stiffly than they used to. They might have an altered posture or have other more subtle symptoms such as increased lethargy or a lack of appetite.

There are lots of things that can be done to alleviate pain from arthritis, including giving anti-inflammatory medication, so take your cat to the veterinarian if you suspect they might be arthritic.

Do Other Animals Sleep Curled Up?

Various cat sleeping positions.

Sleeping in a ball is a warm and cozy position for cats.

Felines are not alone in curling up into a ball while they sleep. Many other animals in the animal kingdom use this way of sleeping to keep themselves warm, comfortable, and safe— even if they are not quite as flexible as the cat.

Dogs will also curl up to sleep, particularly in their beds, they just don’t manage to sleep quite as tightly curled-up as cats do. Most wild mammals of all sizes from mice to bears will sleep curled up to protect themselves and keep warm.

Other Cat Sleeping Positions

1. On Their Back

When cats are truly relaxed and feel completely safe, they sometimes sleep belly-up on their backs. This is a very vulnerable position to sleep in so it tends to just be domestic house cats that sleep like this, rather than wild cats.

2. On Their Side

Cats will often sleep stretched out on their side when they are warm enough and feel safe enough to do so. Some cats might just prefer this position as they feel more comfortable. Pets are more likely to sleep on their side than feral cats as it’s a more vulnerable sleeping position than curling up into a ball.

3. Sat Upright With Paws Tucked Under

Cats will sometimes catnap sitting in an upright position with their front paws tucked underneath them, rather than fall into a deep sleep. This is because it’s a good way to nap while still retaining the ability to move quickly if necessary.

This position is sometimes referred to as the loaf position because it resembles the shape of a loaf of bread.

4. Underneath Something

Your cat might choose to sleep under the bed or under a pile of logs outside. This is likely to make the cat feel safe while they sleep, as well as being their way of demonstrating that they do not want to be disturbed.

5. Eyes Half Open

Cat with heartworm

Cats napping with one or both eyes slightly open are not usually in a deep sleep.

Sometimes cats will nap with their eyelids half open, or with one eye open and one eye closed. This is usually when they feel they need to be on the lookout and remain alert, either because they feel threatened, or because they are waiting for something to happen, such as that tin of food to be opened!


Cats curl into tight little balls when they sleep for the simple reasons that they feel safer, it keeps them warm, and it’s comfortable! Although sleeping curled in a ball is one of the most common ways for your kitty to sleep, cats are well-known contortionists and can sometimes sleep in the strangest of positions.

Look out for your cat’s sleeping positions and learn what’s normal for her. Changes in your cat’s sleeping habits, such as different positions, or sleeping more or less than previously, could indicate an illness. Take your cat to the veterinarian if you suspect that there might be something wrong.

Also Read: Why Does My Cat Sleep On Me?

Frequently Asked Questions

Is it normal for cats to sleep in a ball?

Yes, it is completely normal for cats to sleep in a ball. They curl up while they sleep to keep warm and comfy, as well as for protection from predators. If your cat doesn’t ever sleep curled up in a ball, it might indicate various medical issues, including arthritis, so take them to the veterinarian to get them checked out.

Does a cat trust you if it sleeps next to you?

A cat is at their most vulnerable while they are sleeping so if your cat chooses to sleep next to you, this is a sign that they trust you and feel safe in your company.

Why does my cat curl up in a ball next to me?

If your cat curls up into a ball when sleeping next to you, it doesn’t mean that they don't feel safe with you, in fact, it can mean the opposite! Cats are vulnerable when they’re asleep, no matter what position they’re in, so the fact that your cat chooses to sleep near you means that they trust you.

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About Dr. Joanna Woodnutt, MRCVS

Dr. Woodnutt is a small animal veterinarian and cat behavior and nutrition writer. She's passionate about helping owners to learn more about their pets in order to improve animal welfare. In her spare time, Dr. Woodnutt takes consultations on the small island of Guernsey.

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