temperature happens to be. The basic rule: they stretch out when it is warm, curl up when it is cool.
So you’ll see a cat stretched out in the sun, but never curled up in the sun. If the room is cool, the cat will curl up into a ball, keeping his body heat turned in on himself. Even better, he will curl up into a human lap—or sidle up to an unaggressive dog, or even another cat.