Do warning displays predict striking behavior in a viperid snake, the cottonmouth (Agkistrodon piscivorus)?
Xavier
Glaudas and Christopher T. Winne
Savannah River Ecology Laboratory, The University of Georgia, Aiken, SC
29802, USA
Abstract
Warning
displays are defined as signals designed to intimidate predators or indicate
a proclivity to fight. However, support for the idea that warning behaviors
signal an intent to fight is largely based on anecdotes and isolated observations,
and a complete understanding of antipredator behavior will only be achieved
if specific hypotheses are experimentally tested. Herein, we tested in
a North American viperid snake, the cottonmouth (Agkistrodon piscivorus
(Lacépède, 1789)), the hypothesis that warning displays
serve as a reliable signal to potential predators that a snake will strike.
The cottonmouth exhibits two stereotypical warning displays during predator
confrontation, i.e., mouth gaping and tail vibrations, making it an ideal
study organism to experimentally test the relationship between warning
displays and defensive striking. To test this idea, we recorded the sequence
of defensive behavior — gaping, tail vibrating, and striking —
of cottonmouths towards a standardized predatory stimulus in the laboratory.
As predicted, snakes that gaped during the trials were subsequently more
likely to strike than snakes that did not. In contrast, striking behavior
was independent of the occurrence of tail vibrations. Our results suggest
that gaping behavior — but not tail-vibrating behavior — may
provide an honest signal to would-be predators.
SREL Reprint #3041
Glaudas, X.
and C. T. Winne 2007. Do warning displays predict striking behavior in
a viperid snake, the cottonmouth (Agkistrodon piscivorus)? Canadian
Journal of Zoology 85:574-578.
