Crotalus atrox - Western diamondback rattlesnake

Meaning
atrox stand for "cruel or horrible" in Latin

English name
Western diamondback rattlesnake

Distribution
Crotalus atrox is widely distributed throughout the southern part of the United States and northern Mexico including a few islands in the Gulf of California and there are even some isolated populations in southern Mexico.

Habitat
Seen their large distribution they can be found in a lot of different habitats. Terrains ranging from deserts to rocky hillsides, from pine-oak forests to floodplains. In general the larger concentrations are found in the drier regions below 1500m.

Description
This rattlesnake has an average length of around 120cm but snakes exceeding 150cm or 180cm can be encountered. The maximum reliable recorded length comes from Klauber (1972) with an animal of 213cm. Animals with an even greater length have been reported but never confirmed. Throughout their range there are a lot of different populations resulting in a lot of diversity, some populations reaching maximum adults lengths of just over a meter where as others populations have characteristic markings and/or coloring.
Snakes the central New Mexico region are known for their melanistic appearance where as snakes for Chihuahua tend to have a red ground color and animals from southeastern Arizona a pinkish ground color. Several "morphes" have been found in the wild like albino, pattern less, xanthic and melanistic animals but in general the ground color is gray-brown with 24-45 dark brown to black "diamond shaped" dorsal blotches with partially white edges. Very characteristic for C. atrox is the tail. The tail usually has 4 to 6 black rings that are usually as long or slightly longer than the white/gray spaces between.

Diet
Their diet consists of rabbits, rats, mice, squirrels and birds, but occasionally reptiles and amphibians and large insects will be taken, especially by newborns. They will seek out their prey or lay in ambush next to a trail.

Venom
The venom of C. atrox is as divers as its range, different populations have different "venom types", even age is a factor in the composition of venom. In general atrox venom is very proteolytic and hemorrhagic, some even have neurotoxins (usually found in populations living in the C. scutulatus range). Atrox venom bites in humans often come with significant swelling of the bitten limb (and radiates outwards), pain, ecchymoses, paresthesias, muscle fasciculations, blistering, change in taste and vision, clotting problems and victims may go into shock. Amputation is not uncommon and full recovery is a long-term process.

Extra
C. atrox has a fierce reputation, and will stand its ground, defending it self and this with its large venom yield makes it responsible for more deaths than any other snake in its range. It is the number 2 in snake deaths in the United States.
This is the snake often seen in Western movies.
There are no subspecies recognized, although several of the rattlesnakes on islands in the Gulf of California, which are regarded as full species, are closely related to C.atrox.