I have had two encounters with rattlesnakes over the years. Each time, the snake shook its tail, made some noise, and let me know it didn't much care for me being so close. I eased my way around, gave the snake some respect, and kept on moving. No problem.

Neither of those encounters were with eastern diamondback rattlesnakes (Crotalus adamanteus), the largest rattlesnake species, which can only be found in southern U.S. states such as Florida, Mississippi and Louisiana. That's just 3 percent of the species's pre-Colonial habitat, and now conservation groups are seeking to protect the endemic and emblematic U.S. snake under the Endangered Species Act.

The eastern diamondback was famously depicted on the "Don't Tread on Me" flag during the American Revolution.

According to the petition (pdf) sent to the U.S. Fish & Wildlife Service (FWS) on August 22 by the Center for Biological Diversity (CBD), Protect All Living Species and One More Generation (OMG), there are now an estimated 100,000 eastern diamondback rattlesnakes, down from an estimated historic population of 3 million.

"The eastern diamondback rattlesnake is a wildlife icon of North America," said biologist Bruce Means, president and executive director of the Coastal Plains Institute, in a prepared statement. Means was also one of the petitioners. "Africa has its lion, Asia its tiger, and we can boast of this marvelous 'Don't Tread On Me' snake. Like so many others, it's a wildlife treasure that we must not allow to go extinct. Remaining habitat for the snake must be preserved, and negative public attitudes toward these nonaggressive animals must be reversed."

Much of the threat to rattlesnakes comes from two things that seem contradictory: the public's fear of snakes, and the thousands of rattlesnakes that are harvested from the wild each year for their meat and skin. According to the CBD, there are no limits on annual rattlesnake harvests in South Carolina, Georgia, Florida, Mississippi, Alabama and Louisiana.

Another major threat is a peculiar cultural institution called rattlesnake roundups, during which people catch and slaughter hundreds of snakes, with awards going to the contestants who capture the biggest rattlers. "Sadly, the demise of the eastern diamondback is being incentivized by rattlesnake roundups," stated Jim Ries of OMG. "Converting these events to rattlesnake festivals where the species is celebrated for its value to the ecosystem would continue to generate revenue for local communities while preserving the species."

Not everyone thinks that the eastern diamondback needs protection. Don Childre, a volunteer at the Opp Rattlesnake Rodeo, told The Birmingham News that he doesn't believe rattlesnakes are on the decline in Alabama. The rodeo used to catch 400 snakes a year and now catches 70, some of which are given to researchers. Others are used to teach dogs to avoid rattlesnakes. (The rodeo also serves fried western diamondbacks from Texas.)

But Mark Sasser, a non-game wildlife coordinator with the Alabama Department of Conservation and Natural Resources, disagreed with Childre: "It is evident that there are declines in not only the eastern diamondback, but also in a lot of species that are associated with long leaf pine ecosystems," he told the newspaper. "The most respected herpetologists in the southern United States have well documented the decline of the eastern diamondback rattlesnake. It is not a judgmental opinion; it is a scientific fact."

The next step is for the FWS to review the petition, a process that normally takes a year, but may take longer due to the Service's recent agreement (pdf) to review the 757 species already in its species-protection backlog with a goal of moving them toward being listed as endangered species, a process that will take several years.

Flag photo via Flickr. Rattlesnake photo via Wikipedia. Used under Creative Commons License