Western Diamond-backed Rattlesnake (Crotalus atrox)
This large-bodied venomous snake is distinguished by a series of "diamonds" that run almost the entire length of the body; two distinctive light stripes on each side of the face that angle diagonally (with one stripe in front of and one stripe behind each eye); a tail that is boldly banded in alternating black and white; and, of course, a rattle.
Western Diamond-backed Rattlesnakes from Arkansas may not have "diamonds" that are clearly marked. The snakes may rather appear "dusty", with a spattering of tans, rusts, and creams.
As with all of the pit vipers that occur in Arkansas, the Western Diamond-backed Rattlesnake has a boxy-shaped head, heat-sensing pits, and vertical pupils.
In terms of bulk, this is Arkansas's largest snake.
This species is also known as the Coon-Tail Rattler, D'back, or simply Atrox.
This snake has typically been associated with rugged, rocky, and remote areas. Undisturbed and exposed rocky South- and West-facing slopes that catch a lot of sun may be vital for this snake's continued existence in Arkansas. These areas are especially important to gravid females, which require very hot temperatures for their developing eggs.
The habits and life history of the Western Diamond-backed Rattlesnake is similar to that of the Timber Rattlesnake. Precious little is currently known about Western Diamond-backed Rattlesnakes in the state.
It is likely Western Diamond-backed Rattlesnakes emerge from hibernation in mid- to late Spring. After basking near their den sites for a few days, they will disperse to forage throughout the summer.
The pattern of large movements may be quite predictable for individual snakes, as they may repeatedly hunt the same areas over and over.
Toward the end of summer, males will begin making large straight-line movements in search of females with which to mate. After a female has been located, a male may protect his claim from other suitors. He may even coil directly on top of her in order to hide her from other males. After they have copulated from one time to several times, he will seek out another female.
During this same time, gravid females will be selecting hot, rocky microhabitats. The developing eggs require a significantly higher body temperature of the females than ambient air temperature. The young, which are born in the Fall, are encased in a shell-less egg. They cut through the outer egg membrane using a special egg tooth and emerge within a couple of minutes after being laid. They will stay very near, or even on top of, their mother for several days.
As the nighttime temperatures significantly cool in the Fall, Western Diamond-backed Rattlesnakes begin making their way back to suitable den sites. Snakes are likely to use the very same den site year after year. Newborn babies will scent trail their mothers to a suitable den site and will wait until they emerge in the Spring to hunt for their first meal.
Based on research conducted on Timber Rattlesnakes, it is likely that Western Diamond-backed Rattlesnakes, too, make fairly frequent movements throughout the winter months deep in their dens.
Western Diamond-backed Rattlesnakes are sit-and-wait predators. They search carefully for a spot with recent rodent activity and position themselves for prey to come within striking distance. Cotton Rats are a favorite prey item and Western Diamond-backed Rattlesnakes may coil near or even in their nests. Other prey includes a variety of other rodents and rabbits.
Like Timber Rattlesnakes, Western Diamond-backed Rattlesnakes demonstrate precision and care when striking their prey. Venom is carefully metered for the size and type of prey. Shortly after the strike, Western Diamond-backed Rattlesnakes will scent track the prey to where it has succumbed to the venom. Like all snakes, Western Diamond-backed Rattlesnakes swallow their food whole. A warm microhabitat may be selected until the food is digested.
Western Diamond-backed Rattlesnakes are large and potentially dangerous snakes. They may be more apt to strike in defense than Timber Rattlesnakes (which are usually much more reluctant and unassuming).
The defensive display of a Western Diamond-backed Rattlesnake can be impressive. A snake will raise up the front portion of its body well off the ground and into striking position. It will generally coil around its raised and rattling black and white tail. It will tongue flick slowly and deliberately in exaggerated movements. It will puff itself up with air to make itself look larger. It will hiss. When a Western Diamond-backed Rattlesnake has been severely disturbed, it makes it known that you "don't tread on me".
Western Diamond-backed Rattlesnakes much prefer to avoid confrontation. If given sufficient space and left undisturbed, they remain peaceable. However, it is not wise to tempt one of these snakes to strike in defense as they are quite capable of inflicting serious, perhaps even life-threatening, bites.
This species currently has no special protections in Arkansas. However, it is the opinion of experts in the state that further investigations, perhaps even protections, are needed.
It is clear that Western Diamond-backed Rattlesnakes do not fare well when they cross paths with humans. The negative impact that humans are having on the seemingly small and dwindling populations of this species in the state is of special concern.
Although common in more southwestern regions of its range, the Western Diamond-backed Rattlesnake faces an uncertain future existence in Arkansas. It is the state's largest venomous snake; a beautiful and fascinating large predator. It would be shameful and sad to lose such a powerful symbol of our natural state! My hope is that further studies, protections, and educational programs will be implemented in an effort to preserve this species.