Scientists Are Aiding Timber Rattlesnakes

The researchers are supporting the biological diversity of wildlife in Indiana by helping to stop the disappearance of the snake from the state, said Purdue veterinarian Steve Thompson. Once found in abundance in woods and hills of Indiana, researchers now have a hard time finding them.

"More timber rattlesnakes have been killed by people than people have been killed by timber rattlesnakes," Thompson said. "We both have our place in the ecosystem. In addition, if an animal becomes extinct, we will never know the uses we might have found for it. There's medical research being done now using other reptile venom for treatment of diseases such as diabetes. If the timber rattlesnake disappears, we can't anticipate what predator will fill its niche, overpopulate in their absence or if better understanding could provide an opportunity to help other species, pets or humans."

The snake measures 3-5 feet long and can be identified by its characteristic rattle and the presence of dark bands running across its back. There are about 34 snake species in Indiana, four of which are venomous, including the timber rattlesnake, northern copperhead, cottonmouth and massasauga rattlesnake. Both of the rattlesnakes that are found in Indiana are endangered species and if found should be left alone, according to a state advisory.

Timber rattlesnakes can be slow to defend themselves and ordinarily avoid confrontation, Thompson said. The snake can live to be 20 years old but is endangered largely because of habitat loss and human persecution.

Thompson is implanting radio transistors in the snakes so the Indiana Department of Natural Resources and Purdue biologists can monitor movement and hibernation.

The project calls for eight snakes from the wild to be implanted with the transistors every year for three to five years. Teams search the snake's southern Indiana habitat three times a week and bring them into a lab to implant the device, which is about the size of an AA battery.

From a large brown sack, the snake is placed in a clear, 3-foot-long tube that circulates the general anesthesia while protecting the head during the surgery. Thompson inserts the transmitter at the end of the snake near the rattle, then closes the incision with sutures and tissue glue. The snake is then released in the same location where it was found.

"Pain management is included during and after the surgery so activity levels have been observed to be absolutely normal after the surgery," Thompson said. "The snakes eat, shed their skin and move about regularly."

Radio telemetry allows researchers to determine the location of the hard-to-find animals while they also learn more about the amount of territory each snake utilizes. Researchers are measuring baseline data over a two-year period to determine where and how the rattlesnakes live, said Brian MacGowan, Extension wildlife specialist in forestry at Purdue who is based in Brookville, Ind.

"We can determine if snakes avoid areas where trees are being harvested or logged, or if they use them more frequently than expected," MacGowan said. "By finding the exact location of each snake, we can also measure vegetation and climate variables to see what specific habitat needs they require. All of this information down the road will help us prescribe forest management plans that will benefit this species." 

The rattlesnake project is a small part of a large project among the Department of Natural Resources, Purdue and other universities called the Hardwood Ecosystem Experiment. The purpose of this project is to determine the ecological and social impacts of long-term forest management on public and private lands in Indiana and the central hardwoods region.

The Indiana Division of Forestry and Purdue University Department of Forestry and Natural Resources provided funding for the project.  MacGowan said a Hardwood Ecosystem Experiment Web site would be available later this year.

MacGowan also is overseeing a portion of the project on box turtles with Zack Walker from the Department of Natural Resources. Other researchers from Purdue, Indiana State University, Ball State University and Drake University are involved to study small mammals, bats, songbirds, cerulean warblers and salamanders. Similar projects in the past helped repopulate Indiana's river otters, peregrine falcons and bald eagles.