Ground squirrel tail-flag displays alter both predatory strike and ambush site selection behaviours of rattlesnakes

M. A. Barbour, R. W. Clark
  • Proceedings of the Royal Society B Biological Sciences, July 2012, Royal Society Publishing
  • DOI: 10.1098/rspb.2012.1112

Tail shakes affect snakes

What is it about?

Why do ground squirrels approach rattlesnakes and wave their tail side-to-side (tail flagging)? Using radio telemetry and portable video surveillance equipment, we found that tail-flagging signals a squirrel's vigilance, which deters snakes from striking because the squirrel is ready to dodge the strike. In addition, tail-flagging communicates the presence of the snake to neighboring squirrels, which causes the snake to abandon its hunt early because its unlikely to be successful.

Why is it important?

Our results provide the first empirical evidence of the mechanisms by which a prey display, although frequently given in the absence of a predator, may still deter predators during encounters.


Dr Matt Barbour
University of British Columbia

Most studies of predator-deterrent signals use humans as surrogates for natural predators. Therefore, it is often unknown whether these signals actually deter predators because the responses of free-ranging predators go unexamined. Our extensive field observations of numerous free-ranging rattlesnakes provided a rigorous test of the adaptive significance of squirrel tail-flagging.

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The following have contributed to this page: Dr Matt Barbour