Sistrurus is a genus of pit vipers in the subfamily Crotalinae of the family Viperidae.

[1] Its generic name is a Latinized form of the Greek word for "tail rattler" (Σείστρουρος, seistrouros) and shares its root with the ancient Egyptian musical instrument, the sistrum, a type of rattle.

[3] Sistrurus species differ from the larger rattlesnakes of the genus Crotalus in a number of ways.

They are smaller in size, but also their scalation is different: Sistrurus species have nine large head plates (same as Agkistrodon), whereas in Crotalus (and almost all other viperids), the head is mostly covered with a large number of smaller scales.

[1] Although bites from Sistrurus species are regarded as less dangerous to humans than those from Crotalus rattlesnakes, primarily due to their lower venom yield, every venomous snake bite should be considered serious, and prompt medical treatment should always be sought.