Why no rattlesnakes in Delaware?

The northern copperhead and timber rattlesnake are Delaware's two native venomous snakes The timber rattlesnake can reach a length of 175 cm (4.5 feet) and is the most venomous snake in re state. It has two phases, a yellow phase (dark bands on a lighter background), and a black phase (dark bands on a dark background). On the end of its tail this snake has the characteristic rattle.