Why do squirrels lay flat out?
Squirrels lie flat in hot weather to cool off. In this position, they increase the amount of their body's surface area that is in contact with the ground. If they find the right spot, the ground temperature will be cooler than the surrounding air, allowing a lot of their body's superficial blood vessels to be closer to the cooler ground. This phenomenon actually has a name: it's called "Splooting"