Western Diamondback Rattlesnake
The main scales of the Western diamondback rattlesnake are normally a gray-brown colour though they are sometimes pinkish-brown, brick red, yellowish, pinkish or chalky white. These sit behind the diamond shaped blotches which are coloured dark-gray to brown. There are approximately 24-25 of these blotches on the body. These may begin as rectangles that slowly become rectangular and then morph into the namesake diamonds. The belly is coloured off-white. This species has a black forked tongue.
Western diamondback rattlesnakes have a triangular shaped head. Running from the lower edge of the eye across the head is the postocular stripe which is coloured smoky or dark gray-brown.
As a pit viper they have a pit between their eyes. This senses the body heat of prey so that they can find them better.
Their distinctive rattle can be found at the end of their tail. This consists of two to eight bands which are coloured white and interspaced with white or pale gray. The rattle is formed when they moult as a result of their last few segments of scales not coming off. Newborn rattlesnakes do not actually have a rattle.
The largest confirmed report of a western diamond back rattlesnake measured 213cm (7ft). A more common size for this species is 120cm (4ft) long. They weigh between 1.8 and 2.7kg (4-6lbs).
Western diamondback rattlesnakes are carnivores. They feed upon mice, rats, rabbits, gophers, ground dwelling birds, lizards and other small animals. Lizards are the predominant food source of young rattlesnakes. Food is consumed once every two to three weeks. Food is swallowed whole.
When biting prey it is not uncommon for their fangs to become stuck and come out. These are replaced 2 to 4 times a year.
These animals have an incredibly low need for food. Their intake is equivalent to their weight each year. Most of their water comes from their prey.
North America is the native home of the Western diamondback rattlesnake. Here they can found throughout Mexico and the states of Nevada, Arizona, California, New Mexico, Oklahoma and Texas in the United States of America.
Here they inhabit the dry, rocky areas such as grassland, shrub land, woodland, dried river beds and coastal islands which provide rock crevices and holes in which they can hide. They may also use abandoned mines or old burrows of small mammals as a hiding place.
Breeding season for the western diamondback rattlesnake is in the spring following hibernation. A female will remain still while the male makes the approach and mating takes place. They will spend many hours together mating a number of times during this.
165 days after a successful mating the young are born. 10 to 20 young may be born. Unlike other snakes this species develops inside the mother and then breaks out of its egg just before birth and is born live. After just a couple of hours the young are off on their own to search for food and shelter.
Very few of the young will survive their first winter due to cold, lack of food and predation. Those who do will reach sexual maturity at 3 years old and be able to go on and produce their own young.
Western diamondback rattlesnakes are preyed upon by hawks, eagles, roadrunners, kingsnakes, coyote, bobcats, foxes and other snakes. Cows, antelope, deer and horses will stomp these snakes if they are threatened by them. If threatened they will attempt to use their rattle to scare away predators so that they can save up their venom. If this is unsuccessful they will strike though.
Snakes engage in their own version of hibernation known as a brumation where metabolic rate and activity decline.
Over summer when the days are warm they are nocturnal. As autumn and winter approach they begin to become more active in the late and early periods of the day.
Their venom is not highly toxic when compared to other venoms. They have brilliant delivery systems though which allow them to inject lots in one go. Venom is not just used for defense though. It is used in digestion to break down the skin and internal organs of prey.
The rattle on this snake may move back and forth up to 60 times in just one second.
Western diamondback rattlesnakes are also referred to as adobe snakes, desert diamond-backs, fierce rattlesnakes, spitting rattlesnakes and the Texan rattlesnake.
By Clinton & Charles Robertson from Del Rio, Texas & College Station, TX, USA (Western Diamondback Rattlesnake (Cortalus atrox)) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
By Michael Wifall from Tucson, USA (Western Diamondback #1 Uploaded by berichard) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
Frost, D.R., Hammerson, G.A. & Santos-Barrera, G. 2007. Crotalus atrox. The IUCN Red List of Threatened Species 2007: e.T64311A12763519. https://dx.doi.org/10.2305/IUCN.UK.2007.RLTS.T64311A12763519.en. Downloaded on 27 April 2020.