If hibernation places are scarce, as many as one hundred snakes may share one den. The snakes may even hibernate with other species. In warm weather, Crotalus viridis basks in the sun during the day, but in hot weather they seek shelter during the day and come out to hunt at night. The predators of Crotalus viridis include some predatory birds such as the Red-tailed Hawk. When Crotalus viridis senses a predator, it makes a rattling sound to warn it.
Smaller snakes tend to wait until the predator is closer to begin rattling, as do pregnant females.
Crotalus viridis use their eyes and sensory pits to detect prey and predators. Pits are heat sensing membranes between a snake's eye and nostril on both sides of its face. They can be used to find prey in the dark and can sense something up to 100 yards away. Habitat Crotalus viridis are found mostly in grasslands and prairies, and in brush. Various subspecies can also be found in woods, forests, caves, rock ledges, and alongside streams.