Massasauga (Massasauga Rattlesnake; Eastern Massasauga)
Medium-sized, dark rattlesnake with a short, thick body. Gray to gray-brown, with dark brown blotches down the middle of the back and along both sides. Head is a thick diamond shape with dark stripes extending back from the eyes. Tail has a stubby rattle. Like other venomous snakes, they have “pits” on the sides of their heads, and the pupils are diamond-shaped (not round). The other rattlesnake of north Missouri, the timber rattlesnake, grows much larger and has a rusty stripe down its back.