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Are all rattlesnakes created equal? No, maybe not

New research shows snake venom varies by geography.
New research shows snake venom varies by geography.

If you’re one of the unfortunate few to be bitten by a venomous snake, having access to effective antivenom to combat the swelling, pain and tissue damage to these bites is critical.

But new research by a team of biologists at Florida State University has revealed that creating antivenom is a bit tricky. That’s because the type of venom a snake produces can change according to where it lives.

Mark Marges, a Florida State doctoral student in Professor Darin Rokyta’s laboratory, led a research study that examined the venom of 65 eastern diamondback rattlesnakes and 49 eastern coral snakes from all over the state of Florida to determine whether snake venoms varied by geography.

In the rattlesnakes, geography mattered.

The venom from an eastern diamondback rattlesnake in the Florida panhandle is very different than the venom from a rattlesnake 500 miles south in the Everglades, and this has huge implications for snakebite treatment.

“So if you use just southern venoms when making the antivenom, it would be ineffective against some of the more common toxins found in northern diamondback rattlesnakes,” said Florida State University doctoral student Mark Margres.

Mark Marges, doctoral student at biology at Florida State.
Mark Marges, doctoral student at biology at Florida State.

The research is published in the journal Genetics.

In the rattlesnakes, they found significant variation linked to geography. But, in the coral snakes, they found the venom to be identical no matter where the snakes were found.

“This can tell us a bit of the history and evolutionary patterns of the snakes,” said Kenny Wray, a post-doctoral research associate in Rokyta’s lab. “This suggests that the coral snakes may be recent invaders to the region and haven’t had time to evolve different venoms in different areas.”

This information also will help with the development of coral snake antivenom, because scientists now know there is uniformity in coral snake venom. According to a 2012 estimate by the Center for Disease Control, 7,000 to 8,000 people in the United States are bitten by venomous snakes every year.

Not only are there medical implications, this information is also important for conservation purposes.

The eastern diamondback rattlesnake is being considered for federal protection under the Endangered Species Act. But, if the snakes are removed from one geographic area, they will be irrevocably deleted sfrom the ecosystem altogether.

“If we lose some of these populations, we lose a whole venom type,” Rokyta said. “That really changes conservation.”

Margres’ paper is available for free on FSU’s digital repository for scholarship, DigiNole.