People are known to purposely swerve in the road to kill them. So, just because temperatures may become more beneficial for snakes it doesn't necessarily mean we'll have a plague of snakes. We may, however, have northern expansion of ranges," he said.
Weatherhead inserted tiny transmitters that emit radio pulses into ratsnakes to track their location and behavior. In order to save battery life through the winter months while the snake was hibernating, the transmitters were designed to slow its pulse rate (not the pulse rate of the snake) as the temperature dropped. "The relationship between the change in temperature and how it affects the transistor's pulse rate is pretty precise. We learned that we could predict the temperature of the snake from the pulse rate of the transmitter," he said.
Weatherhead's team also created snake models using a piece of copper pipe filled with water and painted black with a transmitter inside it. They placed the simulated snakes in various microhabitats--under a log, up in a tree, and on bare ground. This provided representative samples of all of the places that are available to a real snake while exposed to a range of weather conditions.
"We got the weather data from standard weather stations, then developed predictive equations from the weather conditions and the model snake's body temperature under each condition," Weatherhead said. "After you've sampled the environment once, then it's just the physical relationship between those environmental factors and the inanimate snake model which very closely mimics a real snake in those same circumstances. You plug the weather data into these equations and you can tell what temperature a snake in each of those environments would be at any time," he said.
Weatherhead said that although temperature-sensitive transmitters have been available for s
|Contact: Debra Levey Larson|
University of Illinois College of Agricultural, Consumer and Environmental Sciences