Our largest venomous snake. Generally tan or yellowish-tan, the timber rattlesnake has markings along the back that are dark brown and change from blotches on the neck to bands near the tail. Often, a dark line extends from the eye along the angle of the jaw, and there is a rust-colored stripe down the back. It has a large rattle at the end of its tail. Like all venomous snakes in Missouri, rattlesnakes have a hole between the nostril and the eye, and the pupils are vertical, like a cat’s.