to understand the reptiles is like putting together the pieces of a puzzle. And the PCC, where black-tailed prairie dogs and prairie rattlesnakes pepper the grassland, offers a significant piece.
“After I visited the center, I realized what a rare opportunity we had to study prairie rattlesnakes in their natural environment,” he says, “so I talked to the PCC, proposed the study to Dr. Rich Reading in the zoo’s Department of Conservation Biology and secured the funds.” Zoos are often involved in conservation project studies in the wild, Shipley says, because they indirectly benefit zoo animals. “The studies help us to understand benefit zoo animals. “The studies help us to understand animals in their natural environment, giving us information on their habitat and helping us to manage what’s left of the natural world.”
Seeking the Snake
Shipley joined up with herpetologist and veterinarian Kevin Fitzgerald to install reflective panels around the PCC property to corral snakes and other small prairie fauna into pit and funnel traps. In the summer of 2006, panels flashed and the sun beat down as the two men walked around the PCC's prairie dog colonies listening for the telltale maraca sound. Aided by four volunteers trained to catch rattlers, Fitzgerald and Shipley checked the traps twice a day, carefully grasping rattlesnakes with steel snake tongs and guiding them headfirst into long, clear tubes to measure their length. “We had to work with the snake’s natural instinct to escaping threat by finding a hole,” Shipley says. It is delicate work, because a snake can back up just as easily as it moves forward. Then the researchers put them into cloth bags to weigh them, injected them with microchips called with Passive Integrated Transponders (PIT tags) and released them near where they were trapped. By the end of the first phase of the study, the team had captured and tagged more than 500 rattlesnakes.
In the second phase, the team implanted radio transmitters into rattlesnakes to track their movements. Shipley shuttled 30 captured snakes to the East Alameda Veterinary Hospital, where Dr. Fitzgerald works. In donated surgery facilities, Fitzgerald anesthetized the snakes and inserted the one-inch transmitters. Once each creature was released back into the wild, its radio signal poured out information about the rattlesnake’s behavior (basking, mating, eating, moving), as well as air and ground temperatures and the rattler’s current GPS location.
Reptile books line the shelves in Fitzgerald’s Alameda Ease office. He treats dogs, cats, and almost anything else, but his passion is evident. “Most people are interested in the questionable nature of rattlesnakes – the coiled bodies waiting to strike, the sharp fangs and poised rattle, the toxic venom – but we’ve found they are an important component to the prairie ecosystem, especially around prairie dog communities,” Fitzgerald says.
As coral reefs are to marine life, prairie dog communities are to grassland flora and fauna: Active communities draw life into their circle. Prairie rattlers occupy empty prairie dog holes around the perimeter of active colonies, but rattlesnakes are fewer in abandoned colonies. “We have not yet concluded the reasons why abandoned prairie dog communities are so desolate, mostly harboring a few rabbits and insects such as black widows and funnel spiders,” Shipley says. Although the team still has much data to analyze, it is clear that the interaction between prairie dog and rattlesnake is crucial to the prairie ecosystem.
A Sensitive Species
With the field research completed, one analysis paper written and one yet to write, Shipley continues to visit the PCC on his time off from the zoo, absorbed by what he calls intricate and purposeful – protecting rattlesnakes. Though they may seem fierce, rattlers are a fragile species. They need precise ranges of heat and cold to digest their food, sleep and even breathe. The snakes have many predators: hawks, coyotes, and skunks, to name a few. Worse, humans kill many rattlesnakes every year because they don’t realize their importance to the prairie ecosystem, Shipley says. “The more we know about prairie fauna, the better equipped we will be to ensure its survival.”
To those who are passionate about snakes, the prairie rattler – with its anvil-shaped head, flicking forked tongue, mottled brown markings and, of course, the rattle – is neither ugly nor repulsive. Shipley almost died after being bitten by a rattlesnake in 2005 but still describes the ritualistic combat dance of male rattlers during mating season with awe. “They face each other, raise their heads high into the air, lurch forward and entwine their necks in an effort to push the other male down to the ground,” he says. “It’s beautiful to watch.”
Copyright 2007 © Brock Publishing. All rights reserved.
