Crotalus durissus is the scientific name of the South American rattlesnake. This venomous pit viper is the most dangerous snake in South America, especially the subspecies C. d. terrificus, and it is the only rattlesnake found in this continent. It belongs to the family 'Viperidae' and to the genus 'Crotalus'. Thus, its main characteristics are its rattle at the end of its tail and the cytotoxic venom. However, its venom also contains high amounts of neurotoxins, such as crotoxin. Therefore, it also affects the nervous system, provoking paralysis and permanent blindness.
Physical Characteristics
The South American rattlesnake body has an average length of 1.25 m, with some adults reaching 1.80 m in length. Like most vipers, the Crotalus durissus has a triangular-shaped head and its eyes have vertical slit pupils. The head features a dark brown bar at the top and a dark post-orbital band. The Crotalus durissus terrificus is brownish, dark grey in color, with yellow lines arranged in rhomboid patterns. The body has large leaf-like scales, which becomes larger at the base of the back. The color of the belly varies and it can be white or yellowish, with light gray spots, becoming darker towards the tail. The tail is also dark gray, with dark and vague crossed bands, and the rattle is brown.
The South American rattlesnake is usually found in the semi-arid plains, especially in coarse grass and scrub-forest undergrowth. It is active at dusk and in the early hours of the morning. It preys on rodents and lizards. The female has a seasonal reproductive cycle. Copulation takes place in the fall and the birth of the young in the summer, with the males competing for the female. Reproduction is Ovoviviparous, giving birth to 4-10 youngs. It is aggressive if it feels threatened, raising its head and one third of the body, in a vertical S-shaped loop.
Venom
Because of the neurotoxins its venom contains, the Crotalus durissus terrificus provoke the following symptoms and medical condition: impaired vision, which might become a complete permanent blindness. There are auditory disorders and ptosis, paralysis of some skeletal muscles, especially of the neck, which becomes limp, with the patient no being able to hold his head upright. Paralysis of the diaphragm and intercostal muscles leads to death, because the patient is unable to breathe. Phospholipase A2 neurotoxins also cause damage to skeletal muscles and possibly the heart, causing general aches, pain, and tenderness throughout the body. Myoglobin released into the blood results in dark urine. Other serious complications may result from systemic disorders (incoagulable blood and general spontaneous bleeding), hypotension, and shock.
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| Above, a Crotalus durissus terrificus found in northern Argentina, Paraguay, and southern Brazil. |
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| The South American rattlesnake's venom contains powerful and lethal neurotoxins. |