Park Looks To Reduce Rapidly Increasing Number of the Non-Native Species
DAVIDSON, N.C., Dec. 21, 2005 – The striking photo broadcast worldwide from the Everglades National Park last fall of a dead thirteen-foot python with a dead six-foot alligator halfway down its gullet raised awareness of the fact that there might be a new king of the swamp!
“Over the last couple of years, the frequency of python sightings in Everglades National Park has increased due to a rapidly expanding python population,” explained Mike Dorcas, associate professor of biology at Davidson College. “Because they are such big animals, there are concerns about their effects on humans and the Everglades ecology.”
Burmese pythons, which are native to Southeast Asia, are popular pets in southern Florida. However, they can grow to more than twenty feet in length, and over the years, many owners cast them into the Everglades when they became too large for care. The snakes have thrived and reproduced in that warm, wet environment, and biologists fear they may be a threat to endangered species of native birds and mammals, and reptiles.
Dorcas and one of his students, sophomore biology major Shannon Pittman, recently traveled to the Everglades to implant radio transmitters in four pythons as part of the park’s effort to control and ultimately remove exotic, non-native plants and animals.
The team of scientists working on the python project also includes Skip Snow of Everglades National Park Service, Ken Rice and Gordon Rodda of the United States Geological Service, Davidson graduate J.D. Willson ’02 of the University of Georgia Savannah River Ecology Laboratory, and biologist Frank Mazzotti.
Dorcas and Pittman were invited to join the project because of Dorcas’ research expertise in placing small radio transmitters in animals. He has conducted three large and numerous small-scale studies using the technology to better understand the habitat selection of various snakes in South Carolina, Idaho, and Davidson.
The technology is ordinarily used by biologists to study animals in order to protect them from human encroachment and extinction. The purpose of this study is different, however. Dorcas noted, “In this case we’re trying to understand what the animal does and what habitat it uses in order to extirpate it.”
The research group conducted day and night searches in grassy fields in and around Everglades National Park, and caught four pythons using bare hands and burlaps sacks. Then, Dorcas and Pittman performed the implantations in a National Park Service lab. It took about an hour to anesthetize each snake, make one-inch incisions in the body cavity just behind the stomach, implant the radio transmitter and temperature data logger, and suture the incision.
The capture, surgery, and release back into the wild of the four snakes went largely according to plan. However, the largest snake captured, at sixteen-feet two-inches and 160 pounds, was exhausted from being handled right after capture, and was placed in the trunk of a rental car instead of a burlap bag so that it would have more space to recover. “By the time that we got back to the lab and opened the trunk, it had recovered and was striking about six feet out of the trunk at us!” Dorcas recalled.
The other three captured pythons measured eleven feet, nine feet, and six feet. Dorcas and Pittman also found many other amphibians and reptiles during their treks in the field, including pig frogs, Cuban tree frogs, an Eastern Diamondback Rattlesnake, rat snakes, and several cottonmouths.
Pittman, who has been conducting research in Dorcas’ lab for the past eight months, enjoyed the opportunity to observe and work with professional biologists in the field. “It’s a really interesting situation in the park with invading species,” said Pittman. “This is not something that I’ll have the opportunity to do very often.”
Over the next year, the Everglades Park research technicians will record the movements and body temperatures of the four pythons into a geographical information system, or GIS. Dorcas and Pittman will examine the data, and hope to co-author several academic papers with the research group about the biology of the snakes and the effects of their presence in the Everglades.
“At this point, we don’t really know what they are doing or how much they threaten indigenous animals,” said Pittman “An important current concern is how big snakes on roads affect traffic.”
This initial trip was a pilot study to help determine the effectiveness of radio telemetry in following this species. The research group hopes to expand the study to track more snakes in the future. Even if the snakes prove not to threaten the Everglades ecosystem, the group will still work to remove them to support efforts to restore the park to its natural condition.
“Pythons are a lot more difficult to find and catch than any of us thought,” said Dorcas. “Anything that we can learn from tracking them will be extremely helpful in finding more.”
Davidson is a highly selective independent liberal arts college for 1,700 students. Since its founding by Presbyterians in 1837, the college has graduated 23 Rhodes Scholars and is consistently ranked in the top ten liberal arts colleges in the country by U.S. News and World Report magazine.