The prairie rattlesnake (Crotalus viridis) is an important predator of prairie dogs and other small rodents. This snake may actually live in prairie dog towns residing in the old burrows of their former prey.
The rattlesnake is not aggressive but like most animals it will defend itself when it feels threatened. The venom of the rattlesnake is a hemotoxin (blood poison). The snake can regulate the amount of venom it injects conserving what it does not need for later use. About one-third of the North American venomous snake bites received by humans are "dry" or venom free.