Cats seem to possess the unique ability to sleep in a countless number of positions and the most unexpected places. Even so, the sleeping posture cats appear to prefer is curled into a tight ball.
They look so peaceful in the curled-up shape and, as it happens, there is a perfectly simple reason why cats curl up in a ball as they sleep.
Do cats curl up into a ball to sleep for a reason?
More often than not, cats choose to curl up into a ball for comfort. Sleeping in a tight ball is an ideal way for cats to retain heat, especially with their tail curled over their face. However, your cat’s ancestors would have slept curled like a ball to protect themselves.
Why our cats’ ancestors curled up into a ball
Early cats were wild creatures and had to develop methods of survival, especially as they slept. An animal is at its most vulnerable when it rests to conserve energy.
Each time our cat’s ancestors went to sleep they would choose a tight space where they felt protected and would make themselves as small and unnoticeable as possible. Curling up into a tight ball was simply the ideal way to achieve this.
The act of curling up covered a wild cat’s underside, or ventral area, so protecting its vital organs from a predatory attack.
Before lying down curled up, a cat would circle several times, a habit still displayed by our pet cats today.

Why today’s cats still sleep curled up
Today, our pet cats often choose to sleep curled up like a ball and there are several reasons why:
Natural instincts
Even though they are safe in our warm houses, cats are still driven by their natural instincts to curl up as they sleep, as their wild ancestors would have. It’s simply a subconscious act on their part.
For comfort
Though cats often sprawl and contort as they rest, curling up into a ball is the most comfortable sleeping position they know.
Though a curled-up cat looks totally relaxed, from this position, a cat is ready to spring into action if the need arises.
When ill
If a cat is not feeling 100%, it may curl up somewhere private where it hopes it will go unnoticed until it feels better.
If your cat is hidden away curled up, keep a close eye on it as it may need a trip to the vet if this goes on for more than a day.
To fit into a small space
Cats have a penchant for squeezing into small spaces which also harks back to their ancestor’s behavior. Adopting the curled into a ball position is the best way to fit into a tiny area.
This is why cats love boxes, especially small ones, and have the ability to fit into impossibly small ones.

To combat the cold
Cats are sensitive to chilly weather and even indoors they can still feel the cold. Just like their predecessors, they know that curling up into a tight ball will conserve their body heat for as long as possible.
If your cat spends a lot of time curled up tightly, especially with its tail over its face, try to warm your house up. You could provide it with a Thermo Kitty Heated Bed (link to more details on Amazon), especially if it’s a senior cat.
Places where cats curl up
Cats can be seen curled up in many places – they aren’t too fussy where they sleep at times.
Your cat might curl up into a ball:
- Next to you
- On your lap
- In a private spot
- On a flower bed
- On your bed at night
- In a box
- on an armchair
- On a hard surface
End of life
Cats, like many animals, sense when they are nearing the end of their life and will hide themselves away, curled up, to do so.
This is because they feel unwell and do not want to be fussed. Again, by curling up, they hope to go unnoticed.

The alternatives to the cat curled up asleep position
Apart from curled up like a ball, cats can adopt many sleeping positions. Here are the main ones and what they say about your cat’s mood.
Sleeping on one side
When a cat sleeps on its side, it is very relaxed and often in the deepest sleep it ever takes.
In this position, a cat is stretched out and exposing its belly meaning it feels safe and unthreatened. It is not as alert as it might be in other sleeping positions.
Snoozing on their back
When a cat chooses to sleep in its back you can be sure it is feeling secure and completely trusts you. It is deliberately placing its most vulnerable area on display.
Resting like a loaf
The loaf position is upright with all four legs tucked under. Cats often sit like this with their eyes open or closed. They are resting but are ready to spring off if necessary.
Slumbering like a contortionist
Of all the sleeping positions a cat can adopt, this is the most amusing.
There are numerous contorted positions that cats adopt and we can only assume they sleep like this because its comfortable.
A cat must feel safe to sleep like a contortionist as, again, its vulnerable belly is exposed to the world.

Why do cats curl up in a ball when they sleep – Conclusion
Cats curl up like a ball to sleep for many totally natural reasons. The majority of the time a curled up cat is not a cause for concern.
Bear in mind that if your cat hides away curled up for any length of time, it might be ill and need to see a vet. Keep a check on it and don’t allow it to stay like this for more than a day.
If your cat is senior and you can’t find it anywhere, you may eventually find it hidden away, curled up like a ball. Be gentle as it may be feeling its time on Earth is up. It’s a sad fact that our cats can’t live forever – though I wish they could.