CRATUS Atrox — Wikipedia

Crotale of Texas, Crotale Diamantin of the West

Crotalus atrox , also called Western diamond crotal or Creakle Du Texas , is a kind of snakes from the Viperidae family ^{[ first ]} . It is found on a large strip in the southwest of the United States and in northern Mexico where it frequents different environments such as deserts, brush, forests. Active from March to October, it is rather daytime in spring and autumn but becomes nocturnal on the strong summer heat. In winter, he hibernates in the ground, sometimes in the company of other snakes. This growing generally reaches 120 or even 150 cm long but some specimens can exceed 2 m , and he weighs 1.8 To 2.7 kg With a record at 6.7 kg . The head, clearly distinct from the body, has a relatively rounded muzzle and the eyes to the split pupils. The body has forced scales and is generally gray-brown or brown in color, rosé, red, yellow or dirty white with a series of 24 or 25 dark spots on the back of rectangular in hexagonal. The tail has 2 to 8 black bands bordered with white, just before the “doorbell”.

Representatives of this carnivorous species feed almost exclusively with small mammals, mainly rodents. He is himself the prey of various animals such as coyotes, foxes, hawks and owls. Viviparous species, the female gives birth to a dozen – maximum 25 – small which are born alive after a gestation of 6 to 7 months. Measuring nearly 30 cm At birth, the little ones are immediately able to bite and inject venom. They only stay a few hours with their mother and then disperse. The venom of this growing is not very active compared to that of other crotals but it produces a lot and is capable of injecting 300 mg with a maximum of more than 700 mg .

This snake reaches an average of 120 cm long, but can reach 150 cm even very exceptionally 180 cm , the record recorded being 213 cm ^{[ 2 ]} . Males are much larger than females, this difference appearing after sexual maturity ^{[ 3 ]} . It weighs from 1.8 to 2.7 kg , with the largest individuals up to 6.7 kg ^{[ 4 ] , [ 5 ]} .

It is generally of a gray-brown color but can also be brown, rosé, red, yellow, pink or dirty white. This color is crossed on the back of a series of 24 to 25 dark spots, most of the time gray-brown with dark brown. The first spots can be rectangular but rather become hexagonal then then can be in the shape of a diamond. The tail has 2 to 8 (generally between 4 and 6) black bands separated by white or gray strips. The head has a dark strip from the eye and descending backwards in the shape of a comma, bordered by a light color ^{[ 3 ]} . The ventral side is white.

The head is clearly detached from the body, with a rounded muzzle. The scales are strongly ford, triangular in the rounded end. The pupil of the eye is split vertically.

• Variability of appearance
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  Black bands on the tail

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  Melanic individual (black)

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  United individual, without any reason

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  Little contrast gray

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Possible confusion with other snakes [ modifier | Modifier and code ]

The distribution of this species covers that of many other snakes. Crotalus scutulatus Also has rings on the tail but the black bands are thinner. Crotalus shivering does not have a caudal ring. At the house of Licricus oreganus These rings are brown-beige. At the house of Lottalus molossus The tail is uniformly black or not very distinct, as well as for Lictalus basiliscus . Triculture Tigris has a smaller head and a more marked back pattern. Crotalus has a gray tail, without rings. Finally members of the genre Sistrus do not have a caudal ring and wider plates on the head ^{[ 3 ]} .

Species distribution area Crotalus atrox According to the IUCN (consulted the February 15, 2013 ) .

This species is found in the southwest of the United States and in northern Mexico. This includes the following states ^{[ first ]} :

Isolated populations also exist in the south of Veracruz and the south of Oaxaca ^{[ 6 ]} .

The species also seems to be present on several islands of the Gulf of California, including San Pedro Mártir, Santa María, Tiburon and the Turner Islands ^{[ 3 ]} .

It is a snake whose period of activity depends on the season: mainly daytime or twilight in spring and autumn it becomes nocturnal and twilight during the hottest months of summer ^{[ 7 ]} .

It frequents coastal plains, rocky hills, and is comfortable in many types of vegetation such as sandy areas, brushwood, pine and oaks forests, as well as in deserts.

It is a lonely animal that only meets other members of its species during the love season. It is mainly active from March to October. The rest of the time he hibernates more or less deeply, because he sometimes heats up in the sun for sufficiently hot winter days. The rest of the time it remains in crevices or burrows, sometimes with other snakes of different species.

Bad climber it remains on the ground whether it is to hunt, heat or hide. When threatened, he wraps up, head out, and waving the “bell” of his tail as a warning.

Feed [ modifier | Modifier and code ]

This snake is a carnivore who actively hunts or who catches in ambush various prey of small to moderate size.

It can do without food for a very long time, up to almost two years. A study has shown that under famine conditions it can reduce its energy expenses by 80 % on average, and that he converts his fat reserves into muscle and skeletal mass ^{[ 8 ]} .

He is a predator of many animals. However, it consumes mainly mammals, especially rodents (almost 95 % of his diet ^{[ 3 ]} ) but it can also tackle birds and reptiles, the latter are generally small lizards mainly driven by the youngest Crotalus atrox . It does not seem to consume insects, and if locusts (among others) have already been found in the stomach of this snake it is probably via prey that it ingests ^{[ 9 ]} .

He is himself the prey of several predators, such as coyotes, foxes, hawks and owls.

Reproduction [ modifier | Modifier and code ]

Male which can be seen the hemipedis, used for reproduction

Crotalus atrox is a viviparous snake. Reproduction takes place in the fall. Gestation lasts 6 to 7 months and a female gives birth to an average of a range with a dozen small. The newborns remain near their mother a few hours before dispersing, which means that the mortality rate in young people is very high.

Newborns measure almost 30 cm and are fully capable of injecting venom from birth.

Venom [ modifier | Modifier and code ]

Like most other American crops, the venom of this species contains proteolytic enzymes, which destroy catabolization tissues.
Its venom, mainly hemotoxic, above all affects blood vessels, blood cells and hearts, thanks in particular to metaloproteinases ^{[ ten ] , [ 11 ]} .
Its venom also contains cytotoxins and myotoxins that destroy cells and muscles ^{[ twelfth ]} . Among the other consequences of the action of this venom, we can also cite localized sparkling gangrene and an alteration of the ability to regenerate tissues ^{[ 13 ]} .

The effects of a bite are pain, internal hemorrhage, strong swelling accompanied by muscle damage, bruises, blisters and necrosis. To this can be added headaches, nausea and vomiting, abdominal pain, diarrhea, dizziness and convulsions.

The median lethal dose (DL ₅₀ ) for this species is 2.72 mg/kg by intravenous injection, 20 mg/kg by intramuscular injection and 18.5 mg/kg by subcutaneous injection, which is much higher (and therefore less toxic) than for many other snakes of this type ^{[ 14 ] , [ 15 ]} .
However, this snake has large venom glands and can therefore inject a large amount of venom into a single bite – between 250 and 350 mg with maximums from 700 to 800 mg ^{[ 16 ] , [ 17 ]} .

The mortality rate of unrealized bites is between 10 and 20 % ^{[ 18 ]} .

The species is classified in the “minor concern” category ( LC ) on the IUCN red list because of its vast habitat area, its supposedly large population, and due to the absence of a precise threat suggesting a significant drop in this population in the near future, this one it being stable ^{[ 19 ]} .

These animals are however often captured and killed for their skin, as food or as a simple amusement especially during Rattlesnake round-up  (in) .

Original publication [ modifier | Modifier and code ]

• Baird & Girard, 1853 : Catalogue of North American Reptiles in the Museum of the Smithsonian Institution. Part 1.-Serpents. Smithsonian Institution, Washington, p. 1-172 ( Full Text ).

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