June 13, 2005
Research Shows Snakes Have Interesting Habits
ST. LOUIS (AP) -- It may not matter to people who hate snakes, but researchers at Washington University have discovered that rattlers are adaptable and have some interesting habits.
For example, they swim and climb trees. Some males go more than six miles a year to look for mates. One snake caught rainwater in its funnel-shaped coil and drank from its own cup.The researchers, who have tracked 28 venoumous pit vipers for six years, also found that the snakes seem to prefer habitat "edges" between a forest and a road or field.
"Edges aren't all that bad," said Corey Anderson, a doctoral student in biology. "Timber rattlesnakes are thought of as these sensitive, secret creatures. ... It'd be shocking to people if they knew how many den locations I have along I-44."
That would shock many people who accept the idea that snakes are a threat to humans. There were 1,245 rattlesnake bites, with only one death, reported to the American Association of Poison Control Centers in 2003. That compares to the 44 people killed by lightning in 2003, according to the National Weather Service.
Wayne Drda likes the snakes so much he gives them cute names like Groucho, Abraham and Lucyfer. Drda, 65, volunteers as a researcher at the Washington University's Tyson Research Center near Eureka.
Drda, 65, recently wielded an antenna on a forested hilltop at the center. He listened for the beep of a radio transmitter embedded in the body cavity of Yanni, a 4 1/2-foot-long rattler.
Veterinarians place the pinkie-sized transmitter in the snakes' body cavities, usually with a U-shaped tong and plastic buckets. The transmitters, which cost about $300 each, have revolutionized the study of snakes. Researchers also use infrared instruments to measure snakes' temperatures, and Global Positioning System units to record their locations.
Reseachers don't know how many snakes live at Tyson. Drda guesses about 200 adults live in the 2,000 acre preserve.
Ryan Turnquist, 18, another research assistant, is well trained at finding rattlers: He has caught and raised eight snakes and has received Greater St. Louis Science Fair honors for his work with snakes. Drda has a breeding colony of 35 bull snakes at his home.
"They're herp kids," said Anderson, referring to herpetology, the study of snakes. "Maybe their moms didn't let them have a dog."
At the Washington University biology department, Anderson analyzes the snakes' paths from the time they emerge from dens in April to their hibernation in October.
He found that the snakes followed similar paths every year and also noticed the snakes avoided the vast wooded interior of the research center. Many instead clustered near the Meramec River flood plain or in an area along Interstate 44.
"It's almost like the snakes prefer not to use the woodlands," he said.
The edge habitat has two advantages, said Chris Phillips, a herpetologist with the Illinois Natural History Survey. They have more prey for snakes and help the cold-blooded animals regulate their temperatures as they move from sun to shade.
From 1880 to 1980, there were at least 100 rattlesnake sites along the Mississippi River between Alton and the Wisconsin border, Phillips said. Now, there are only a half-dozen sites.
Nationwide, the rattlers exist in 30 states. Thirteen states, including Illinois but not Missouri, list the timber rattlesnake as threatened or endangered.
Information from: St. Louis Post-Dispatch, http://www.stltoday.com