Sistrurus miliaris is a type of venomous snake commonly found in the United States. This snake is also known by several other names, including pigmy rattlesnake, ground rattlesnake, and massasauga. These synonyms reflect the snake's small size, as well as its preference for living on the ground. Like all rattlesnakes, Sistrurus miliaris has a distinctive rattle that it uses as a warning signal. Its venom is highly toxic and can cause serious harm or death to humans who are bitten. Despite its dangerous reputation, this snake plays an important role in many ecosystems, where it helps to control rodent populations.