Prairie Rattlesnake (Crotalus viridis) - Endangered
Description: 35 - 45 inches. Prairie Rattlesnakes are tan, brown, or greenish in color, with darker brown blotches along the back. The blotches may become lighter in color and become bands near the tail, which has a light colored rattle on the end. The eyes have elliptical, cat-like pupils. The head is shaped like a spade, and has two light lines on each side. One of these lines starts behind the eye, and continues back to the neck. The other starts in front of the eye, and extends down and along the upper lip.
Similar Species: No other rattlesnakes are found within the range of the in Iowa. Many non-venomous species of snakes in Iowa will wag their tail against grass and other ground debris to produce a rattle-like sound, but rattlesnakes will hold their tails off the ground while rattling them. All non-venomous snakes in Iowa have round pupils.