Cats curling up in a ball is one of the most common sleeping positions for felines, and it serves several protective purposes beyond looking adorable. According to Dr Joanna Woodnut, a principal reason is to retain heat.
She wrote: "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."
Heat conservation and protection
When a cat is curled up with its legs tucked beneath its body, a C-shaped spine and the tail wrapped around the body, it is maintaining its vital organs warm. Occasionally a cat may have its tail tucked over its nose, which protects one of the cat's most heat-sensitive body parts. The tighter the cat is curled into a ball, the colder it is likely to be.
Beyond warmth, the position offers protection. In the wild, sleep is a dangerous business, so cats evolved to shield their most vulnerable body parts. When they curl up, their soft underbellies are protected by their limbs, making it far more difficult for them to be injured while sleeping. When tucked up like this, they feel more relaxed and secure, not unlike how swaddling a baby helps to soothe them.
When to be concerned
In almost all cases, a cat sleeping in a curled position is nothing to worry about. It is a safe and perfectly natural sleeping position for them to adopt most of the time.
However, there are some important warning signs that may require a visit to the vet. If a cat is unwell or in discomfort, it may curl up even tighter or tuck itself away in a secluded spot. Simply being curled up alone is not cause for concern, but if other changes are noticed, such as a loss of appetite, an unwillingness to be touched, or shifts in toilet habits, it may be worth consulting a vet.
