South American Rattlesnake

South American Rattlesnake

Tropical rattlesnake, Neotropical rattlesnake, Guiana rattlesnake. In Spanish: víbora de cascabel, cascabel, cascabela. In Portuguese: cascavel. In Suriname: Sakasneki

Kingdom
Phylum
Subphylum
Class
Order
Suborder
Family
Genus
SPECIES
Crotalus durissus
Population size
Unknown
Life Span
15 years
Length
2
5
mft
m ft 

Crotalus durissus is a highly venomous pit viper species found in South America. It is the most widely distributed member of its genus. Currently, seven subspecies are recognized.

Appearance

The South American rattlesnake is a large highly venomous pit viper species found in South America. The color and pattern of its body are quite variable. The head has a dark brown bar at the top, with a dark post-orbital band. The color of the belly varies, it can be white or yellowish, with light gray spots, becoming darker towards the tail. The tail is usually gray, with dark and vague crossed bands.

Distribution

Geography

South American rattlesnakes are found in South America except for the Andes Mountains. They occur in Colombia and eastern Brazil to southeastern Peru, Bolivia, Paraguay, Uruguay, and northern Argentina (Catamarca, Córdoba, Corrientes, Chaco, Entre Rios, Formosa, La Pampa, La Rioja, Mendoza, Misiones, San Juan, San Luis, Santa Fe, Santiago del Estero, and Tucumán). They also occur on some islands in the Caribbean, including Morro de la Iguana, Tamarindo, and Aruba. These snakes can live in a wide range of habitats, however, they prefer savanna, grasslands, shrubland, and semi-arid zones. They can also be found and in the drier, sandier areas, and sometimes occur in forests.

South American Rattlesnake habitat map

Climate zones

South American Rattlesnake habitat map

Habits and Lifestyle

South American rattlesnakes are solitary and prefer to live on their own. They are more active at dusk and in the early hours of the morning. Although very dangerous they are not aggressive towards humans; when feeling threatened the snake will raise its head and front one-third of the body, in a vertical loop in the shape of '' S ''.

Seasonal behavior

Venom

Bite symptoms are very different from those of Nearctic species due to the presence of neurotoxins (crotoxin and crotamine) that cause progressive paralysis. Bites from C. d. terrificus in particular can result in impaired vision or complete blindness, auditory disorders, ptosis, paralysis of the peripheral muscles, especially of the neck, which becomes so limp as to appear broken, and eventually life-threatening respiratory paralysis. The ocular disturbances are sometimes followed by permanent blindness. 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. Hemorrhagins may be present in the venom, but any corresponding effects are completely overshadowed by the startling and serious neurotoxic symptoms. Acute renal failure is considered as the main cause of death. The mortality rate of cases without specific serum treatment is 72%, and 11% in cases with specific treatment. The LD50 value is 0,047 mg/kg IV, 0,048 mg/kg IP and 1,4 mg/kg IM. The SC median lethal dose varies widely: 0.0478 mg / kg, 0.6 mg / kg, 0.171-0.193 mg / kg, 78 μg / kg and 74 μg / kg. The lethal dose for 60 kg humans is 18 mg, while the venom yield is 100 mg. A study points out that the rattlesnakes in Roraima, Brazil have two types of venom, with different characteristics of individuals of the same species found in other regions, the two types of venom are known as '' yellow venom '' that attacks the nervous system, causing paralysis, and also kidney and respiratory failure, causes muscle pain and makes urine dark, and the "white venom" is hemorrhagic and causes bleeding.

Diet and Nutrition

South American rattlesnakes are carnivores. They feed mainly on rodents, possibly due to the greater abundance and availability of these prey and lizards.

Mating Habits

REPRODUCTION SEASON
fall
BABY CARRYING
4-14 young
FEMALE NAME
female
MALE NAME
male
BABY NAME
snakelet

South American rattlesnakes are seasonal breeders with the males competing for the female. They mate in the fall and give birth to their young in the summer. Females are ovoviviparous, meaning that they carry the eggs inside their bodies and give birth to live young. They usually produce 4-8 snakelets but are capable of giving birth to up to 14 young.

Population

Population threats

There are no major threats to South American rattlesnakes at present.

Population number

The IUCN Red List and other sources don’t provide the number of the South American rattlesnake total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.

Coloring Pages

References

1. South American Rattlesnake on Wikipedia - https://en.wikipedia.org/wiki/Crotalus_durissus
2. South American Rattlesnake on The IUCN Red List site - https://www.iucnredlist.org/species/178477/7554740

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