Iyalin Crotalidae na nufin dangin macizai masu dafin da aka fi sani da pit vipers ko pit adders. Ana samun waɗannan macizai a ko'ina cikin Amurka kuma sun haɗa da nau'in nau'i irin su rattlesnakes, copperheads, da cottonmouths. Sunan "Crotalidae" ya fito ne daga kalmar Helenanci "krotalon," wanda ke nufin "rattle" ko "castanet," yana nufin sautin raɗaɗi na musamman da wasu nau'in rattlesnakes suka yi.