Virtually everyone out there has heard the term “poisonous snake” before. What many people do not realize is that a snake is not poisonous in the traditional sense of the word. Snakes and spiders are venomous. The difference is that poison is ingested, whereas venom is injected. Snakebites are generally harmless as the largest number of snakes are non-venomous. Of all the snakes in North America, only the rattlesnakes, copperheads, cottonmouths and coral snakes are venomous. Ironically, these snakes and their various subspecies have markedly different snake venom.
Venom generally works in two different ways. Most rattlesnakes, copperheads and cottonmouths are what is referred to as Pit Vipers. Pit vipers generally have hemorrhagic venom. In simple terms, hemorrhagic venom causes the snake bite victim to bleed to death from the inside. Hemorrhagic venom is also likely to cause massive tissue damage and scarring.
A coral snake, which is closely related to the cobra family, has what is called a neurotoxic venom. Neurotoxic venom attacks the central nervous system and can cause cardiac arrest as well as cessation of breathing. As a rule, neurotoxic venom is much more dangerous than hemorrhagic venom.
One interesting snake is found in the United States is the Mojave rattlesnake. The Mojave rattlesnake actually has both venoms, and is particularly dangerous. All venomous snakes have some level of both types of venom as a rule, but the Mojave has enough of each for both to be a problem.
As a rule, venomous snake bites are not a problem in North America. The odds of coming across a venomous snake in North America are fairly remote unless you find yourself in the wilderness often. Still it is a good idea to keep in mind how venom works, and the dangers that it can create. Venomous snakes are hesitant to use their venom on anything other than a meal. This is because they have precious little venom, and wasting it on an inedible human makes no sense.