Massasaugas have become rare in Missouri because of habitat destruction and are on the state's Rare and Endangered Species list. Human deaths caused by its bite are rare, but tests show that the massasauga's venom is highly toxic. Massasaugas eat mice, shrews, frogs and lizards. This is one of the smallest species of rattlesnakes in North America. General color is light grayishbrown with rows of small, dark brown spots on the back and similar spots on each side.
Most specimens also have a rustcolored stripe down the back.
The belly is usually gray. The pygmy rattlesnake has a thin tail and a tiny rattle. This species lives under rocks on cedar glades and is so secretive that few people encounter it. The sound of the vibrating rattle is a faint buzz like the sound of a grasshopper. Food includes small lizards, snakes, frogs and mice.