Name: Eastern Diamondback Rattlesnake (Crotalus adamanteus)
Range: Southeastern United States
Diet: Carnivorous. Primarily feeding on small mammals, but will also feed on birds.
Conservation Status: IUCN – Least concern
This species, along with the bald eagle, has attained iconic status in the United states, and its cultural significance cannot be overstated. The snake appears on the Gadsden flag, which is considered to be one of the first flags of the United States.
Though not listed as threatened by the IUCN, this species’ range has been diminished to about 3% of what it was prior to European settlement of North America. They are locally threatened in many areas and are now completely absent from some areas. One of the greatest threats to this species is habitat destruction, albeit in an unusual way. This species avails of open canopy pine forests and savannas, which are becoming rare due to human intervention. These snakes have an important relationship with a tree, the long leafed pine, which is extremely fire tolerant. The cycle of burning and regrowth ensures the pine forests never grow too dense, which maintains a habitat that is suitable for the small mammals the EDB preys on. However, efforts at controlling wildfires have disrupted this cycle, and these open canopy forests are being overtaken by dense growth.
The Eastern Diamondback is the heaviest viper in the Americas, and is possibly the heaviest venomous snake globally, rivalled only by species such as the stocky Gaboon viper, or the very long, King Cobra. This large, powerful, snake can deliver significant doses of venom and, while generally not aggressive, should thus be treated with a great deal of respect.
The venom contains the enzyme crotalase, which mimics the enzyme thrombin found in the prey species. The venom essentially hijacks the body’s natural clotting process. The clotting protein fibrinogen, is soluble in blood until it comes into contact with the enzyme thrombin. The thrombin converts fibrinogen into a matrix of insoluble fibrin strands which would ordinarily reinforce the initial plug created by platelets during the clotting process. In the case of an envenomation, the crotalase triggers the mass production of fibrin clots which causes a whole suite of problems for the unfortunate victim. The insoluble fibrin strands can trigger hemolysis (the destruction of red blood cells) due to the friction-damage caused to the cells as they flow past. The clots may also block capillaries, and this, combined with the hemolysis, deprives the surrounding tissue of oxygen, leading to cell death (necrosis). While venom is a complex cocktail of toxins, and no one element can typify the venom’s properties, it is this necrosis and haemorrhaging that are the most prominent symptoms displayed following an Eastern Diamondback bite.
The typical venom yield of a EDB bite is well in excess of the dose needed to kill an adult human, however, due to the availability of antivenin, fatalities are now quite rare.
Gadsden Flag -by Lexicon, Vikrum Own work. Licensed under CC BY-SA 3.0 via Commons – https://commons.wikimedia.org/wiki/File:Gadsden_flag.svg#/media/File:Gadsden_flag.svg
Everglades NPS Flickr stream.