Crotalus ravus - Mexican pygmy rattlesnake

Meaning
Ravus: in Latin stands for grey.
Brunneus: means brown.
Exiguus: means "small" or "insignificant".

English name
Mexican pygmy rattlesnake

Distribution
Crotalus ravus is only found in the mountains of central and southern Mexico, like the highlands of Morelos, Puebla and Oaxaca. Vertical distribution is estimated between 1500 – 3000m. Above sea level.

Habitat
C. ravus inhabits primarily forests of the temperate zones, especially pine-oak forests. They can also be found in temperate grasslands, cloud forest, high altitude thorn scrub and tropical deciduous forest.

Description
This rattlesnake species generally reaches a length between 40 to 65cm but specimens larger then 70cm are known.
Body colour can range from light grey to dark brown, even within same populations there is tremendous variety. The 22-44 blotches on the back are of much darker shade, usually dark grey to black with lighter centres. The head is patternless and the postocular stripe is usually not visible.

Diet
The diet of adults mainly consists out of small rodents but amphibians and other reptiles are also eaten.

Venom
The toxicity of the venom is relatively low and is considered to be somewhere between Sistrurus catenatus and S. miliarius. Local effects will probably consist of swelling, ecchymosis and pain, other effects main include muscle fasciculation, numbness and necrosis may set in.

Extra
For a long time placed under the Sistrurus group, because of the 9 large head plates, but studies of the hemipenis (by Campbell & Lamar) showed closer relations with the Crotalus group.