Western Diamondback Rattlesnake
Crotalus atrox

f5.6 @ 1/5000s, ISO:800, Nikon D3S w 300mm

"Western Diamondback Rattlesnake," Wikipedia, the free encyclopedia. Like most other American pit vipers, the venom contains proteolytic enzymes. Proteolytic venoms are concentrated secretions that destroy tissues as a result of catabolism of structural and other proteins, which help in disabling prey. The venom of C. atrox is primarily hemotoxic, affecting mainly the blood vessels, blood cells and the heart. The venom contains hemorrhagic components called zinc metalloproteinases.[16][17] The venom also contains cytotoxins and myotoxins which destroy cells and muscles that add to the failure of the cardiovascular system.[18] In addition to hemorrhage, venom metalloproteinases induce myonecrosis (skeletal muscle damage), which seems to be secondary to the ischemia that ensues in muscle tissue as a consequence of bleeding and reduced perfusion. Microvascular disruption by metalloproteinases also impairs skeletal muscle regeneration, being therefore responsible for fibrosis and permanent tissue loss after bites from this species.[19] General local effects include pain, heavy internal bleeding, severe swelling, severe muscle damage, bruising, blistering, and necrosis; systemic effects are variable and not specific, but may include headache, nausea, vomiting, abdominal pain, diarrhea, dizziness, and convulsions. Hemorrhagins causing bleeding is a major clinical effect this can lead to death and sickness.
Green Valley, Sierra Vista, Arizona