Biology Ph.D. student Joel Johnson and co-author Eric Roth, University of Oklahoma, found that when test snakes were confronted with danger their first reaction was to retreat. Smaller snakes, although just as likely to flee or strike as larger snakes, were more likely to issue warnings. But, over all, test snakes of all sizes were more likely to exercise the better part of valor: they ran away. Rather, slithered.
"Our results show a gradual decrease in response to a predatory encounter with an increase in body size," said Johnson.
Johnson and Roth collected 46 variable-sized western cottonmouths in Texas and cared for them in the laboratory for months before testing. Using a metal snake tong with a welding gloved fitted to the end, researchers nudged the snakes' faces. As the snakes responded, researchers documented seven common antipredator behaviors - escape, defensive posture, tail vibrations, musk release, mouth gapes, strikes and bites. After testing, the snakes were released to the wild where they were captured.
"We found that antipredator behavior varied with body size," said Johnson. "The bigger the snake, there was less defensive response and fleeing became more common."
Were the bigger snakes older and wiser? Perhaps.
"Younger snakes may exhibit an elevated defense response," said Johnson. "Assuming the younger snakes were less experienced, older snakes may have been better able to evaluate the risk and respond accordingly."
Johnson and Roth published their study in Behavioral Ecology (Vol. 15 No. 2: 365-370).
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