Crotalus cerastes - Sidewinder

Meaning
cerastes stands for the horned in Latin
laterorepens - Latin - later - side and repens - creeping or crawling - refers to the curious style of "sidewinder" locomotion
cercobombus Gr. kerkos - tail and Gr. bombos - to buzz, deep tone

English name
Sidewinder
Crotalus cerastes cerastes – Mohave Desert sidewinder
C. c. cercobombus – Sonoran Desert sidewinder
C. c. laterorepens – Colorado Desert sidewinder

Distribution
The Sidewinder range is from southern Nevada, to northeastern Baja California and western Sonora into Mexico, east into central Arizona, and west to the base of the desert side of California's mountains.

Habitat
C. cerastes is solely a desert dwelling snake that lives primarily in desert areas until 1800m above sea level with wind-blown sands, especially where sand hummocks are topped with vegetation. Also found in hardpan, open flats, rocky hillsides, and other desert like areas, especially those grown with creosote bush, where the terrain is open and not obstructed by rocks or vegetation, which allows the broad side winding locomotion.

Description
This species has three different sub-species all looking very similar. Their average length is between 50 and 80cm, (the largest recorded was a C. c. laterorepens 82.4cm Klauber 1956). Females grow larger then males, this is unique among rattlesnakes. They tend to have a pale creamy, brown, pink or grayish ground color, and 28-47 irregular blotches. The distinct feature of this species of snake is the upturned supraoculars, giving them their hornlike appearance. The use of the upturned scales is still unclear, some stating it is for protection from the sun and/or sand. An interesting feature is that the supraoculars cannot be moved by the snake it self, but when pressure is applied from above, the "horns will fold, forming an eyelid, protecting the eye. Maybe for when the snake moves between rocks or underground in borrows?
The sidewinder is the only North-American snake with true sidewinding motion. The biomechanics of this motion is very complex but if fact the snake throws its body in front of its head in a loop, forming an S shape. Using this motion the snake is able to move very fast in the lose shifting sand. It is also a way for the snake to have minimal contact with the hot sand as only two small parts of his body touch the sand at one time, forming a very characteristic pattern.
The differences between the three subspecies are very subtle but when taken in account the location and proximal lobe one should be able to determine which subspecies.

Diet
C. cerastes is primarily nocturnal, escaping the excessive daytime heat, but may also be active during daylight when the temperature is more moderate. It is a well adapted ambush predator, it sits buried beneath the surface of loose sand with just the top of the head showing, usually waiting near kangaroo rat warrens, and lizard or rodent trails. The young mainly eat lizards but when growing bigger shift to a primary diet consisting of rodents.

Venom
The venom of C. cerastes in humans can cause pain, swelling, bleeding Coagulopathy (blood clotting problems) and ecchymosis (blood seeping into surrounding tissue) . Other effects may be dizziness, chills, nausea and shock.