Eastern Diamondback Rattlesnake
Crotalus adamanteus
Summary 7
Crotalus adamanteus is a pit viper species found in the southeastern United States. It is the heaviest though not the longest venomous snake in the Americas and the largest rattlesnake. No subspecies are currently recognized.
Size 8
Length: 244 cm (approx. 96 in)
Geographic range 9
C. adamanteus is found in the southeastern United States from southeastern North Carolina, south along the coastal plain through peninsular Florida to the Florida Keys, and west along the Gulf Coast through southern Alabama and Mississippi to southeastern Louisiana.
Venom 9
This species has the reputation of being the most dangerous. While not usually aggressive, they are large and powerful. In proportion to its length, it has the longest fangs of any rattlesnake species. It has a very high venom yield, an average of 400–450 mg, with a maximum of 858-1,000 mg. Brown gives an average venom yield of 410 mg (dried venom), along with LD50 values of 1.3-2.4 mg/kg IV, 1.7-3.0 mg/kg IP and 14.5–10 mg/kg SC for toxicity. The estimated human lethal dose is 100–150 mg.
The venom contains a thrombin-like enzyme, "crotalase", capable of clotting fibrinogen, leading to the secondary activation of plasminogen from endothelial cells. Although the venom does not activate platelets, the production of fibrin strands can result in a reduced platelet count, as well as the hemolysis of red blood cells. Even with this defibrination, however, clinically significant bleeding is uncommon. Nevertheless, the venom does exhibit high hemorrhagic activity. It also contains a low-molecular-weight basic peptide that impedes neuromuscular transmission and can in theory lead to cardiac failure. This peptide is similar to crotamine from C. durrisus terrificus, and makes up 2-8% of the protein found in the venom. In general, the venom can be described as highly necrotizing, mildly proteolytic and containing a large phosphodiesterase fraction. It stimulates the release of bradykinin that can result in severe pain, as well as profound, transient hypotension.
CroFab and Wyeth's ACP are effective antivenoms against bites from this species, although massive doses may be needed to manage severe cases of envenomation. Generally, ACP is very effective at countering the defibrination syndrome that is often seen, but may do little for low platelet counts. Wyeth's ACP is no longer being manufactured.
Sources and Credits
- (c) Zack, some rights reserved (CC BY-NC-SA), http://www.flickr.com/photos/87418376@N00/141054848
- (c) Lillie, some rights reserved (CC BY-NC), uploaded by Lillie
- (c) Daniel Wakefield, some rights reserved (CC BY-NC), uploaded by Daniel Wakefield
- (c) 2011 Todd Pierson, some rights reserved (CC BY-NC), http://calphotos.berkeley.edu/cgi/img_query?seq_num=390241&one=T
- (c) Irma Linda Sanchez, some rights reserved (CC BY-NC), uploaded by Irma Linda Sanchez
- (c) gailhampshire, some rights reserved (CC BY), http://commons.wikimedia.org/wiki/File:Eastern_Diamond-backed_Rattlesnake._Crotalus_adamenteus_-_Flickr_-_gailhampshire.jpg
- Adapted by Shannon Foreman from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Crotalus_adamanteus
- Adapted by Shannon Foreman from a work by (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28889095
- Adapted by Shannon Foreman from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Eastern_diamondback_rattlesnake
