There are approximately 30 known species of rattlesnake in the world. These include the Eastern diamondback rattlesnake, Queretaran dusky rattlesnake and Western diamondback rattlesnake. Common among all species of rattlesnake are the telltale rattles found on the tail of the reptile. Used as a warning device when alarmed, the rattles are vibrated by rapid twitching of the tip of the tail. Nearly all species of rattlesnake are venomous and most are considered to be potentially deadly to humans as well as other much larger mammals.
Some species of rattlesnake are named for the region in which they can be found, such as the Mexican west coast rattlesnake, Catalina Island rattlesnake and the South American rattlesnake. Other species of rattlesnake are named for the method of motion they use. Perhaps the most common snake named for this type of action is the sidewinder.
The most typical method of naming a species of rattlesnake is to use the type of terrain the snake is most commonly found in, such as the Baja rattlesnake, timber rattlesnake and the rock rattlesnake. With nearly 30 species and many more sub-species of the snake found in various countries around the world, naming the species often falls on physical or visual identification traits and characteristics. Common of this type of naming are the Mexican small-headed rattlesnake, speckled rattlesnake and the twin-spotted rattlesnake.
Of all species of the reptile, the largest is commonly the Western diamondback rattlesnake. This snake can commonly reach lengths of 6 feet (1.83m) and more. The length of a snake is typically associated with its striking distance, making the effective striking distance of a large Western diamondback to be nearly 12 feet (3.7m). An aspect that makes the rattlesnake even more dangerous is the fact that not all rattlesnakes have rattles. Circumstances such as skin shedding and injury can often leave a rattlesnake not as easily recognizable as compared to hearing the shaking of the rattle. Most species of rattlesnake can be best identified by their triangle-like head shape, with the head being much wider at the base of the head and narrowing towards the nose.
The venom from most species of rattlesnake is a valuable commodity, with the collection of venom being the key to the manufacture of anti-venom used to treat snake bites. Each species of rattlesnake requires its own anti-venom if it is available. As a last resort, the anti-venom from a similar species of rattler is used. In some areas of the world, the hunting of the rattler for its venom is surpassed only by the hunting of the snake to be used as a food for humans.