The snake with the deadliest poison is the olive sea snake, but like all sea snakes, it is shy and rarely spotted. Far more dangerous are land-living species, such as cobras and rattlesnakes. The eastern diamondback rattlesnake is said to be the most dangerous snake in North America. In fact, all venomous snakes can be dangerous. People should not try to kill them, as they have their own place in the ecosystem.