rattlers are by far the most dangerous . you see a rattle snake has what is known as necrotic venom and it basicly digests the flesh it touches. also when most snakes strike they only deliver enough venom to kill a rat or a frog. when a rattler envenomates somthing he delivers every ounce of venom all at once.so a large rattler could deliver as much as an ounce of venom all at one time. and that means you could lose the affected limb. or if bitten near a major artory painful death as your heart is digested into liquid................nice huh . cottonmouths are not that bad they just look and act bad. i have been bitten 3 times by cottonmouths and never spent any time in the hospital nor lost any apendages. a corralsnake is the most venomous snake in north america . they are a rear fanged snake and thier fangs are tiny so they almost have to chew on a large animal to get any venom in them. a copperhead is very quick to strike but delivers a dry bite in most defensive situations and when venom is present it is a minute amount. so dont be scared of snakes . treat them like a loaded gun and respect that they can hurt you if you are not careful.