The Western diamondback rattlesnake is a venomous rattlesnake species likely responsible for the majority of snakebite fatalities in northern Mexico and the greatest number of snakebites in the U.S.A. Adults commonly grow to 120 cm in length and is the second largest-bodied species of rattlesnake, behind only its close cousin the eastern diamondback rattlesnake. The colour pattern generally consists of a dusty-looking grey-brown ground colour, but it may also be pinkish-brown, brick red, yellowish, pinkish, or chalky white. Patterning is seen along the back of the snake in distinctive diamond shapes, hence the name “diamondback rattlesnake”. The tail has two to eight black bands separated by ash white or pale grey interspaces which then leads into the infamous “rattle”. Like most other American pit vipers, the venom contains proteolytic enzymes. Proteolytic venoms are concentrated secretions that destroy tissues as a result of catabolism of structural and other proteins, which help in disabling prey.
The Western diamondback rattlesnake is found in the United States from central Arkansas to south-eastern and Central California, south into Mexico. The species habitat ranges from flat coastal plains to steep rocky canyons and hillsides. It is common to see the Western diamondback rattlesnake on rural blacktop roads in early evening, because of the heat retention of these surfaces, as ambient temperatures drop.
This species feeds mostly on small mammals, including prairie dogs, pocket gophers, wood rats, wild mice, voles amongst others. They have also been sighted preying on lizards and birds. They are ambush predators and prefer to hunt at night or in the early morning. The species have been known to go for up to two years without food in the wild.
The Western diamondback rattlesnake is solitary except during the mating season. Mating occurs in Autumn with females giving birth to as many as 25 live young, which may be as long as 30cm. The young are fully capable of delivering a venomous bite from the moment they are born and leave their mother within only a few hours of their birth – thus the mortality rate is very high.