Have rattlesnakes stopped rattling?

Published Aug 7th 2011 in Wildlife

“Because humans and feral hogs kill every rattler that rattles, the only rattlers left aren’t rattling anymore.” I have heard that from lots of folks – from folks that call in to the radio show “The Rugged Llano Estacado” on KWEL1070 AM on Friday mornings at 8 a.m., in many emails to me at the Sibley Nature Center, from drop-ins and audience members at Sibley Nature Center programs, and from folks asking if it is true on my Facebook page. Some of the people are very adamant about the truth of the statement. Somehow it has attained the level of “unimpeachable truth” for some people. I have always called it “urban myth.”

Deborah loves to make sure I am doing due diligence on my responses to questions from folks on our local ecology and history, so she went online and searched for opinions on the subject. She found heads of herpetological associations saying it was true, and other such folks saying no. I love Deborah dearly – and her ability to mentally challenge me (and often times dance circles around me) is one of the many reasons! I am thankful for every time she “shakes a finger at me” and challenges me to verify what comes out of my mouth.

What follows is an excerpt from a story in Arizona; “Steve Reaves, owner of Tucson Rattlesnake Removal, said rattlers have stopped rattling in recent years in order to avoid being killed. “Normally when a rattlesnake announces its presence, people kill it,” Reaves said. “The snakes that aren’t genetically predisposed to rattling are the ones that are left to breed. They rely on their natural camouflage and stay still so predators won’t notice them. Basically what’s happening is we’re breeding a rattlesnake that doesn’t intend to rattle.” Jerry Feldner, sergeant-at-arms in the Arizona Herpetological Society thinks he first noticed the non-rattling behavior six or seven years ago. “The rattlesnakes people see are the ones where they walk or hike,” Feldner said. “Snakes alongside the trails have learned that rattling gets them in trouble.”

Stéphane Poulin, curator of herpetology at the Arizona-Sonora Desert Museum, said the theory that snakes have recently stopped rattling is a myth.“In the last 25 or 30 years I haven’t seen any change overall with rattlesnakes,” Poulin said. “Overall, rattlesnakes just don’t rattle very often. Most of the time they use their camouflage and try not to be seen. Rattling and striking are unconnected. A snake can rattle all it wants without striking or strike without rattling.”

Randy Babb, a biologist with the Arizona Game and Fish Department says,“Most of the work that has been done indicates rattlesnakes actually seldom rattle,” he said. “Their primary defense is not being seen. As long as they feel they’re not being seen, they lie quiet and let whatever potential predator there is wander by. Only when the animal has been disturbed or it’s quite clear they’ve been spotted will they go ahead and rattle.”

On Facebook there are several “groups” mostly made of up of professional biologists, and at least one that is just for herpetologists. I posted a query to one of the groups, as in – “is there any validity to the theory…” – and it was reposted to another. Dr. Harry Greene, professor of ecology at Cornell University, posted; “I don't think there's a shred of published evidence, though the idea has been around since the 19th century.” Dr. Ivan E. Parra-Salazar, who consults for a number of organizations and governmental agencies in both the United States and Mexico, commented; “There is also an individual "personality": siblings kept under the same conditions can have extremely different behavior. Most of the time, rattlesnakes do not rattle, unless they feel threatened.”

It appears there is a general consensus among academic biologists that it is unlikely that rattlesnakes have become quieter and have stopped rattling. Among the avocational herpetologists there seems to be a divided opinion. I couldn’t hear rattlesnakes for several years until I got some good hearing aids, but the few that I have seen since then have rattled when annoyed, but have not rattled if left alone. There is an old West Texas saying – “Never be the third in line walking down a trail. The first person wakes the rattler up, the second makes it mad, and the third person gets bit.”