Fig. 4.75 Crotalus durissus durissus.

Distribution

See link "Distribution" at the top of the page for detailed information.

  Map 59 Crotalus durissus sspp. along the old classification (including the new species from Mexico and Central America: Crotalus culminatus, C. simus, C. tzabcan, C. totonacus).

According to the new classification, the species Crotalus durissus and its various subspecies are now found only in South America. As stated above, the former subspecies from Mexico and Central America are now classified as separate Crotalus species (Campbell and Lamar 2004, Wüster et al. 2005).

1. Crotalus durissus cascavella: Brazil
2. Crotalus durissus collilineatus: Central and northeastern Brazil
3. Crotalus durissus cumanensis: Colombia, Venezuela, Los Testigos Islands and Margarita Island, possibly western Guyana?
4. Crotalus durissus durissus: Northern Guyana, northern Suriname, northern French Guiana, northern Brazil
5. Crotalus durissus maricelae: Venezuela
6. Crotalus durissus marajoensis: Eastern Brazil
7. Crotalus durissus ruruima: Eastern Venezuela, northern Brazil
8. Crotalus durissus terrificus: Southeastern Peru, Bolivia, Paraguay, northern Uruguay, southeastern Brazil, northern Argentina 
9. Crotalus durissus trigonicus: Southwestern Guyana, northern Brazil
10. Crotalus durissus unicolor: Aruba Island
11. Crotalus durissus vegrandis: Eastern Venezuela

Biology

The only rattlesnake in South America (in Mexico there are many more species). Appearance typical of rattlesnakes and displays the characteristic warning behaviour (see Crotalus spp.). Length on average 1 m, but can reach up to 1.5 m and longer.

Basic colouring in shades of grey or brown, sometimes with red or olive-green elements. Usually present are dark stripes both sides of the spine from the top of the head reaching far down the neck. They gradually resolve into larger rhombi along the top of the body.

They prefer semi-arid regions, open, savanna-like grasslands, as well as sparse forest. By and large absent in rainforest areas. Sometimes also found in plantations. Generally found at 700 m above sea level, but in northern South America isolated occurrences at altitudes of over 2,000 m above sea level.

When threatened they behave like other rattlesnakes, but are restrained with the use of their rattle. They can raise the upper third of their body in an S shape, in order to locate their opponent visually and then to strike.

Risk

One of the most dangerous rattlesnakes and one of the most dangerous of all snakes in the Americas. The huge area of distribution, very potent venom in fairly large quantities and a definite willingness to defend themselves are important factors in their dangerousness. In Brazil and probably also in other countries in their area of distribution, C. d. terrificus is probably the most dangerous subspecies. After the lance heads (Bothrops spp.), it is the most common cause of snake envenoming. In the first half of the 20th century as well as in the 1950s and 1960s, 12% of treated cases ended fatally. Untreated cases apparently had a mortality rate of 72% in the same period (Rosenfeld 1971).

In more recent times, an average of 20,000 snakebites are registered each year in Brazil, almost 10% of them caused by C. durissus. The mortality rate is estimated at 3.3% and is thus much lower than in the past (Ribeiro 1990b).

A study from southeastern Brazil documented only one fatality from 87 treated cases (C. d. collineatus and C. d. terrificus) (Silveira and Nishioka 1992).

The Neotropical rattlesnake is very popular among terrarium owners. Thus it is not infrequently responsible for acute and complicated cases of envenoming in Europe.

Literature (biological)

Bolanos 1984, Campbell and Lamar 1989, 2004, Chippaux 1986, Hoser 2009, Lancini 1986, Pérez-Santos and Moreno 1988, Villa 1984, Wüster et al. 2005

The Reptile Database