Western diamondback rattlesnake
The Western diamondback rattlesnake (Crotalus atrox) is a venomous snake native to the southwestern United States, extending from California to Arkansas. Known for their distinctive diamond-shaped markings, these snakes typically grow to about three feet in length, although they can reach up to six feet. They possess unique adaptations, including brilles that protect their eyes, vertically elliptical pupils, and heat-sensing pits that aid in hunting. This species is ovoviviparous, with females giving birth to live young after a gestation period of three to four months.
While they are the most commonly bitten snakes in North America, fatalities from their bites are rare, with more people dying from lightning strikes each year. Western diamondbacks are generally active during the day in cooler months and shift to nocturnal behavior as temperatures rise. Despite their fearsome reputation, they tend to avoid confrontation unless threatened. With a lifespan of up to 20 years, these snakes play an important role in their ecosystems but are also subject to human impact, including collection for food and skin.
Subject Terms
Western diamondback rattlesnake
More people are bitten by diamondback rattlesnakes than by any other venomous, or poisonous, snake in North America. But even with that fact, more people are still killed each year by lightning than by being struck by a venomous rattlesnake.
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Viperidae
Genus: Crotalus
Species: Atrox
Western diamondback rattlesnakes mate in the spring and fall. Female western diamondback rattlesnakes are ovoviviparous. This means their young develop and hatch inside eggs inside their mothers' bodies and are then born live. The females have a gestation period (duration of pregnancy) of between three and four months. They then give birth to between 2 and 24 young, depending on the size of the female. The young are usually born in late July or early August.
Young western diamondback rattlesnakes grow the first fold of their rattle when they shed their skin for the first time. Each time they shed their skin a new fold is added to their rattle. The longer a snake's rattle, the quieter the sound is that it makes. Throughout a western diamondback rattlesnake's life it may grow and loose folds of its rattle. Older segments sometimes drop off, as new ones are added. Rattlesnakes use their rattles to warn off predators.
Western diamondback rattlesnakes have brown, beige, black, and gray patterned skin. They are called diamondback for the diamond-shaped markings on their backs. Like other vipers, western diamondback rattlesnakes have wide heads which hold their large venom glands. They also have brilles, pits, and vertically elliptical pupils. Brilles are the transparent, or clear, coverings over their eyes. Since western diamondback rattlesnakes do not have eyelids, they use brilles to protect their eyes from dirt and dust. Western diamondback rattlesnakes also have vertically elliptical pupils. Pupils are the black areas in the center of the irises, or colored parts of the eyes, which open and close to let in light. Vertically elliptical pupils have the black portion running up and down in the center of the iris. Finally, western diamondback rattlesnakes have two holes above their upper lips called pits. Pits are sensory organs which identify highly sensitive temperatures known as infrared heat rays. Being able to sense these rays, help the western diamondback rattlesnakes to tell the difference between an animal and its surroundings. Western diamondback rattlesnakes usually grow to be about three feet (one meter) long, but some may grow to be over six feet (two meters) long. Western diamondback rattlesnakes usually weigh between one and two pounds.
Western diamondback rattlesnakes live in the desert sand and the dry, desert grasslands of southwestern North America from California to Arkansas. During the cooler months, western diamondback rattlesnakes are diurnal, or day active, but during the warmer months they become nocturnal, or night active.
As western diamondback rattlesnakes slither through the sand, dirt, and rocks, they flick their tongues into the air to examine their surroundings. Like other snakes, western diamondback rattlesnakes pick up chemicals on their tongues. They take these chemicals back into their mouths and place them in special organs. These organs are specifically designed to identify which chemicals are present in the environment. This information is important to western diamondback rattlesnakes because it helps them trail prey, recognize predators, and find mates.
Huge numbers of western diamondback rattlesnakes are collected, killed, skinned, and eaten each year. Although they have a reputation for being vicious killers, western diamondback rattlesnakes rarely attack when they are not threatened or cornered.
Western diamondback rattlesnakes have a life span of up to 20 years.