SAN ANGELO, Texas — There are times when I write this column that the information about an animal is scarce and hard to come by. However, at other times the material that is available is almost overwhelming.
There is so much information (true and false) that I would like to present that a column like this would quickly take up more space than is allowed.
Such is the case with the Western diamondback rattlesnake.
The Western diamondback rattlesnake (Crotalus atrox) occurs from central Oklahoma through the western two-thirds of Texas westward to the southeastern border of California and south to the state of San Luis Potosi, Mexico. In Texas, it is the most commonly encountered venomous snake in both the Trans-Pecos eco-region and the Tamaulipan thornscrub of South Texas. It is a habitat generalist, occupying a variety of habitats ranging from desert scrub near the Permian Basin to high elevation pine-oak forests of the Davis Mountains.
Western diamondbacks are the second largest venomous snake in the United States, slightly exceeded in size only by the Eastern diamondback rattlesnake of Florida and other East Coast states. It is by far the largest venomous snake that occurs in Texas. Adult Western diamondbacks can achieve lengths up to seven feet, although the average is much smaller. Most individuals max out at a length between four and five feet in total length.
The body coloration of Western diamondbacks can vary (depending on the soil type where it occurs) from a chalky gray to a dull reddish brown. Along the spine is a series of darker diamond-shaped markings that are bordered by a black and white line, hence the name diamondback. A common nickname among those who encounter this serpent frequently is coon-tail, which refers to the black and white banded tail. These tail bands are of nearly equal width, one characteristic used to distinguish it from the more dangerous Mojave rattlesnake that inhabits the Trans-Pecos area of Texas as well.
The head is distinctly wider than the neck, giving this animal the famous “diamond-shaped” head. The pupils are elliptical, and the rattle is large and is capable of being heard from several yards away.
Diamondbacks, like other snakes, do not hibernate in the true sense of the word, but rather employ an activity known as brumation. This means that the snake’s metabolism, heart rate and breathing all slow down to a near stop, but they are quite awake and aware of their surroundings.
They often congregate in large numbers in “dens” to spend the long periods of inactivity of winter, and once temperatures achieve a level of warmth that the snake finds tolerable, usually in early to mid-March, the males begin leaving the dens in their quest to mate.
Females release a pheromone that attracts the males, and many times more than one male will encounter a female that is receptive. During these encounters, the males will participate in a dramatic “dance” as they entwine their bodies together in a wrestling match style event. The winner is the one who is able to pin the other to the ground, and mating ensues upon the dominant male’s victory.
Diamondbacks are oviviparous, which means they give birth to living young, and the foot-long neonates (which number from 4 to 25) are typically born in late summer and early fall. Other than having a “button” on the end of the tail, they are exact replicas of the adults and are fully capable of fending for themselves, including having fully functional fangs and venom apparatus.
Western diamondbacks defend themselves in a variety of ways, with the main defensive mechanism being that of camouflage. Even with the gaudy patterns and colors, this snake blends in well with its primarily brushy habitats.
The second defensive plan is that of crawling away from a potential predator while rattling its tail slightly. If this does not deter its assailant, then it will begin to curl up in a defensive “s-coiled” stance and aggressively vibrate its tail, causing the rattling sound to get louder.
This behavior is typically a final stand, so to speak, and many times an encounter with a diamondback does not come to this point. Out of the 300 or so diamondbacks that I encounter each summer, less than 10 percent resort to this tactic, with most being satisfied to avoid any confrontations.
The last defensive mechanism is biting and injecting a deadly venom into a would-be attacker. This venom, depending on a huge variety of factors, can be lethal to humans, although few human fatalities actually occur.
Despite these venomous propensities, the Western diamondback is actually beneficial because it preys primarily on small mammals such as mice and rats.
When participating in outdoor activities, the risk of encountering a Western diamondback is slim. If such an encounter occurs, remember that this animal, despite its harmful capability, is more afraid of you than you are of it, and it would prefer to be left alone. Most bites from this species occur when people make an attempt to either capture or kill this snake.
The best course of action is to walk, don’t run, in the opposite direction, making both you and the snake more at ease.