Why do cats sleep curled up?

Cats like to sleep curled up in the winter to keep warm. Their body temperature is much higher than the ambient temperature, and to maintain a constant body temperature, they need to reduce heat loss. In summer, cats won't sleep curled up but will lie directly on the floor or lean against the wall, as their bodies need to dissipate heat efficiently.

Cats curl up when they sleep because they feel cold. The position of wrapping their head and feet against their abdomen helps prevent their body temperature from dropping. When their body temperature is much higher than the ambient temperature, they need to reduce heat loss to maintain a constant temperature. If a cat has a long tail, they will also use it as a scarf to cover their body, feeling very warm. Although cats are not as sensitive to cold as humans, those from desert regions still fear the cold. Therefore, when the temperature drops to about 15 degrees Celsius, they will curl up to sleep.

As the temperature rises slightly, cats' originally tightly wrapped bodies will become slightly relaxed. If the temperature continues to rise and becomes very hot, cats will stretch their entire body and lie down with their limbs spread out. In short, cats sleep like thermometers.

Additionally, sensitive cats will also curl up, which makes them feel secure, just like most people who sleep insecurely. For a four-legged cat, curling up can not only stick to the ground but also escape promptly. When cats sleep curled up, their ears can touch the ground, allowing them to detect hostility. If something attracts their attention, they will erect their ears to receive messages, widen their eyes to focus on potential threats or prey, and then stop to assess the opponent while remaining alert - all of which are naturalcat behaviors.