Many snakes native to the southern United States are nocturnal, which means that they are AWAKE at night, or at least, in the dusk and dawn hours. Most of the venomous snakes hunt mostly at night, so rather than sleep, they're wide awake. Daytime-hunting snakes include the Racers and Coachwhips, which do not see well in the dark, so they will go to sleep at night. Most of the others will be awake, though, especially in hot weather, since the sun will cause snakes to overheat and die, so they must wait until it cools off to get out and find food and water.