Meeting Abstract

50.3  Jan. 6  Target tracking and behavioral release of venom spitting in cobras YOUNG, Bruce/A.*; BOETIG, Melissa; WESTHOFF, Guido; Washburn University; Washburn University; University of Bonn bruce.young@washburn.edu

Multiple species of African and Asiatic cobras can expel (or �spit�) their venom during defensive encounters. Previous studies have shown that this spitting behavior is consistently associated with angular displacement of the cobra’s head about it’s neck. We hypothesized that these cranial movements of the cobra were a way of tracking the movements of a predator and, in that way, allow the cobra to more accurately target the spit. As a corollary we hypothesized that there is likely a particular movement, or suite of movements, of the predator that serves as a behavioral release for the spitting behavior. To explore these hypotheses one of the authors, serving as �predator,� wore a faceshield incorporating custom-made accelerometer chips and circuit boards that accurately tracked the movement of the author’s head in all directions. Multiple standard and high speed digital video cameras recorded both the movement of the �predator� and the cephalic displacements of the cobra during the spitting behavior. Bipolar EMG leads were implanted into the cobra’s neck muscles responsible for rotary displacement of the head in the sagittal and frontal planes. A laser pulse generated by the data acquisition system and visible on the video records enabled a 2 msec temporal resolution of the integrated data set. Our data suggest that spitting cobras have a reaction time of approximately 20 msecs and that their ability to track a target varies, at least in part, on the direction and magnitude of the target’s movements.