Meet the scourge of the east: The Eastern Diamonback Rattlesnake. Biggest venomous snake in the USA. It is so aptly named for the diamond patterns on its body. Lovely to look at, but distance is needed for these bad boys are highly venomous. Just one bite is enough to kill a full grown man. Like all rattlers, their tail ends in a rattle made of special scales. The rattle is used to warn trespassers of its presence.