Head wagging and visual acuity in flying snakes (Chrysopelea)

Meeting Abstract

72-1  Friday, Jan. 5 13:30 – 13:45  Head wagging and visual acuity in flying snakes (Chrysopelea) ZAMORE, S*; SOCHA, JJ; Virginia Tech; Virginia Tech jjsocha@vt.edu

The arboreal flying snake is an adept glider with keen vision, but little is known about the role of their visual system in glides and other behaviors. These animals are well-camouflaged and elusive, making their ecology difficult to study. However, the ecological role of the visual system can be gleaned from their behavioral responses. For example, flying snakes are known to track planes and birds overhead, suggesting they may be predated upon by birds. These qualitative observations can also help illustrate visual functions driving some behaviors.

Recently, we have conducted optomotor experiments to measure visual acuity in flying snakes. These experiments involved lateral, visual field rotation for 1-4 minutes in a constant direction. During these experiments, we observed a novel behavior: a lateral, oscillatory translation of the head that occurs with a frequency of about 2 Hz. In the context of this experiment, this behavior does not appear to be used for motion parallax because it occurs in response to whole-field visual motion, not a small-field target, as seen in other animals. This behavior is similar to a recently-described oscillatory head motion in garter snakes that was characterized as a type of behavioral camouflage. We hypothesize that this novel flying snake behavior, head wagging, is another example of such behavioral camouflage.

In this talk, we present evidence of head wagging in two species of flying snake (Chrysopelea paradisi, Chrysopelea ornata) in response to whole-field visual motion, and describe the triggering stimuli. This characterization provides useful insight into the behavioral roles of vision in locomotor behaviors, including non-gliding behaviors. Supported by NSF 1402558 and 1351322.

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