The Western Diamondback Rattlesnake is a venomous species of rattlesnake found primarily in Mexico and the southern portion of the United States, including the states of Texas, Arizona, New Mexico, and California (Klauber, 1997, p. 25). In Mexico, they can be found in northern Veracruz, Hidalgo, and Sinaloa. This type of rattlesnake is found in several terrestrial biomes including deserts, dunes, grasslands, and savannas (Ingmarrson, 2002).
The scientific species name for this rattlesnake is Crotalus atrox (Klauber, 1997, p. 30). It has many common names including Texas diamondback, adobe snake, spitting rattlesnake, coon tail, fierce rattle snake, and Arizona diamond rattlesnake.
While the life cycle of the Western Diamondback Rattlesnake does involve eggs, rattlesnakes give birth to live young (Clark et al., 2014). After the fertilization of the eggs, the female rattlesnake carries the eggs internally for approximately ninety days. When ready, the eggs hatch inside the female rattlesnake, resulting in live birth. This type of reproductive system is referred to as viviparous (“Rattlesnakes,” n.d.).
A newborn rattlesnake measures around ten inches long at the time of its birth. While they do not yet have a rattle, the young rattlesnake is extremely venomous (“Rattlesnakes,” n.d.). Young rattlesnakes will attempt to strike a target repeatedly if they are disturbed. Despite their small size, newborn rattlesnakes are capable of delivering a dangerously venomous bite as soon as they are born.
Young rattlesnakes are very independent at a young age. At seven to ten days old, they shed their skin and gain a rattler (Ingmarrson, 2002). It is at this point that they leave the nest in search of food. Their life span can be in excess of twenty years in captivity; however it tends to be less than that in their natural environment due to factors such as predators and human spread.
Structure and Function – The Reproductive System
Rattlesnakes reach sexual maturity at around three years of age (Clark et al., 2014). Mating typically occurs in the spring, as the rattlesnakes emerge from hibernation. During the mating process, the male takes an active role. The female remains passive. After crawling on top of the female, the male presses his tail beneath the tail of the female in order to inseminate her (“Rattlesnakes,” n.d.). Fertilization can occur for months after mating, as the female is able to store the semen within her body. The female rattlesnake can carry anywhere from four to twenty five eggs at a time, resulting in an average of nine to ten young being born live. The young are usually born in late summer or early fall. Female rattlesnakes typically give birth every two to three years.
Over time, the venom of the Western Diamondback Rattlesnake has evolved. It is now proteolytic, a concentrated and advanced poison capable of destroying cells and tissues through intramolecular digestion (Klauber, 2007). Klauber (2007) states that the hemotoxic nature of its venom has enabled it to survive generation after generation. The toxins present in the venom induce muscle damage in the prey of the rattlesnake, thus doing away with predators and organisms that threaten its existence. A rattlesnake bite can cause severe pain, bleeding, swelling, blistering, and convulsions. Young rattlesnakes are able to defend themselves against extinction, since even small snakes produce this venom (Klauber, 2007).
The diet of the rattlesnake has also evolved over time to ensure that they survive from one generation to the next. They mainly consume small rodents such mice, as well as lizards and birds. The digestive system of the rattlesnake has adapted to slow digestion, which aids in the storing of energy (Klauber, 1997, p. 57). This is especially important during the winter months, as they can go long stretches without food. Energy stores are also important for female rattlesnakes, since they are known to not consume anything during gestation. Such traits ensure that they survive in their environments generation after generation.
Reyes-Velasco and colleagues (2013) list the phylogeny of the Western Diamondback Rattlesnake as follows: Kingdom – Animalia, Phylum – Chordata, Subphylum – Vertebrata, Class – Reptilia, Order – Squamata, Suborder – Serpentes, Family – Viperdae, Subfamily – Crotalinae, and Genus – Crotalus.
The rattle of the rattlesnake is hollow and comprised of a protein called keratin, which is the same protein that makes up human hair and nails (Ingmarrson, 2002). Each time that a rattlesnake sheds, which is two to three times a year, a new segment is added to its rattle. Counting the segments on the rattle is not an accurate measure of the snake’s age, however, because shedding occurs at different rates. Segments of the rattle can also break off. The rattlesnake is capable of moving the rattle quite quickly, back and forth sixty or more times each second. The Western Diamondback Rattlesnake is distinguished from other types of rattlesnakes by the white and black bands that are seen just above the rattle (“Rattlesnakes,” n.d.).
The long term outlook for the Western Diamondback Rattlesnake is good. It is currently classified as Least Concern on the IUCN Red List (“Rattlesnakes,” n.d.). The rattlesnakes are classified as such due to their widespread distribution, large population, and overall lack of predators. Humans also continue to play a role in the rattlesnake population. The rattlesnakes are often drawn out of their natural habitats using gasoline, where they are then killed and used for food, their skins, and for entertainment purposes.