Rattlesnakes are native to the Americas.They are the largest of the venomous snakes in the United States and are found in most habitats, including mountains, deserts and beaches. Rattlesnakes use their rattles when they feel threatened, but they can also strike at distances up to 1/3 their body length. Their venom is a complex mixture of enzymes that destroys blood or paralyzes nerves of the victim. In addition to being a defense mechanism, the venom primarily helps snakes hunt and feed.
Copperheads are reddish to golden brown and about 18 to 36 inches long. They freeze when frightened. They are more common in the eastern United States, and can be found in forests, rocky areas, swamps or near water sources. Copperhead venom weakens the blood vessels of the victim, causing internal bleeding. It also causes respiratory difficulties and lack of muscle control.
Also called water moccasins, cottonmouth snakes can reach 55 inches in length. The adult is dark tan, brown or nearly black, with dark cross bands. Cottonmouths are frequently found near water, and are more abundant in the southeastern states. The Eastern Cottonmouth (Agkistrodon piscivorus) produces a toxin called piscivorin, which can cause muscular contraction. Cottonmouth venom is hemotoxic, meaning it can destroy blood cells and reduce blood coagulation, which cause severe bleeding.
Coral snakes often hide in leaf piles or burrow into the ground. They are similar to non-venomous king snakes, which also have red and black bands. However, in coral snakes the red bands touch the yellow bands, while king snakes have white bands. Coral snakes are more common in southern areas of the United States. They produce one of the most powerful venoms found among North American snakes. It contains a neurotoxin venom that can paralyze the respiratory muscles and suffocate the victim within few hours.