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Western Diamondback Rattlesnakes
Author: Patsy Jones
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Species: Crotalus atrox |
Description:
The Western Diamondback is the largest western rattlesnake, ranging in
size from 30-85 inches (76-213 cm). Their color varies depending on the soil background from gray, brown,
pink, or yellowish colors with distinct diamond-shaped blotches on their back. The blotches are light brown
to blackish in color with fainter, smaller blotches on the sides of their bodies.
Another distinguishing characteristic is the presence of broad black and white rings about equal in width
at the end of their tail, thus they are often called the “coontail” rattlesnake. At the tip of the tail,
there are a series of loosely connected segments comprising the rattle.
Western Diamondbacks belong to a group of poisonous snakes known as pit vipers because they have a loreal
pit located on the side of their face. This sensory organ is highly sensitive and can detect infrared
radiation. This allows them to “see” their prey even in complete darkness. They smell with their forked
tongues, flicking them out to pick up molecules in the air to detect the presence of their prey or potential
predators.
Geographic range:
Texas Horned Lizards have a geographic range that extends over
most of Kansas, Oklahoma, Texas, and eastern and southern New Mexico, generally in areas below 5,000 feet
elevation. They are also found extensively in northern and eastern Mexico.
Habitat:
Western Diamondbacks live in a wide variety of habitats in arid and
semiarid regions of the Southwest. Desert, grassland, shrubland, open pine forests, woodlands, and riparian
areas near river bottoms are all places where they could be found. They are most often found in areas that
are rocky or brushy. They hibernate through the winters, often in dens with other Western Diamondbacks, in
burrows underground or in the spaces between rocks.
Food Web:
Western Diamondbacks hunt and eat a variety of animals, mostly rodents
such as mice, rats, Kangaroo rats, rabbits, and squirrels. They will also eat lizards and birds.
When they locate a potential prey target, they quickly stab the victim with their fangs, injecting powerful
venom that is quickly toxic to the small animal. Then they back away and wait for the victim to die. They
swallow their prey whole. Their jaws can open so wide they can even eat food that is many times larger than
their mouth opening.
Rattlesnakes are an important part of the desert's ecosystem since populations of rabbits and rodents would
quickly overwhelm the available food resources if their numbers were not kept in check by the presence of
these predators.
Reproduction and Development:
Western Diamondbacks bear their young in the summer
and fall. Males and females mate in the summer, and the pregnant female carries the developing eggs for
several weeks. The eggs hatch inside her and the young snakes are born live, going off to live
independently right away. From 4-23 young are born at a time.
Behavior:
Western Diamondbacks are one of the most dangerous snakes in the western
United States because they will aggressively defend their ground. They will usually warn off any potential
predator with their rattle, and strike readily when they feel threatened. In the spring and fall, they may
be seen near dens in large numbers basking in the rays of the sun. They are mostly nocturnal and
crepuscular (coming out at dawn or dusk), but are often seen abroad during the day as well.
Conservation:
Western Diamondbacks are numerous in the arid regions of the southwest
and are not considered endangered. Many people are ignorant of these creatures and they are often killed
indiscriminately.
Taxonomy:
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia; Reptiles
Order: Squamata
Family: Viperidae
Genus: Crotalus
Species: Crotalus atrox
References:
Peterson, Roger T. and Stebbins, Robert C., Peterson Field Guides:
Western Reptiles and Amphibians, 1985, Houghton Mifflin Co., Boston.
Tweit, Susan J., Seasons in the Desert, 1998, Chronicle Books, San Francisco.
Tweit, Susan J., The Great Southwest Nature Factbook, 1992, Alaska Northwest Books, Anchorage.
Williamson, Michael A., Hyder, Paul W., and Applegarth, John S., Snakes, Lizards, Turtles, Frogs, Toads,
and Salamanders of New Mexico—A Field Guide, 1994, Sunstone Press, Santa Fe.