The Herpetological Journal

pp. 185-191
Authors: Young, Bruce A.; Boetig, Melissa & Westhoff, Guido

Abstract: Though spitting cobras are able to “spit” their venom even before they fully emerge from the egg, little is known about how this remarkable defensive behaviour is manifest in hatchlings. This study examined three aspects of spitting behaviour in hatchling red spitting cobras (Naja pallida) – the amount and dispersal of the spat venom, the kinematics of the head during spitting, and the distance of both the target and the spat venom. Hatchlings spit more venom relative to their body mass than adult snakes, and produce similar patterns of spatial dispersal of the spat venom. Hatchlings exhibit cephalic oscillations during spitting that are similar to those reported in adults, although the magnitudes of these movements are more exaggerated in the hatchlings. The distance covered by the hatchling's spat venom is much less than that of the adult cobra, and, unlike the adults, the hatchlings routinely spit at targets well beyond their effective spitting range. These results suggest that while the same basic mechanisms underlie spitting in hatchlings and adults, these mechanisms undergo a distinct ontogenetic refinement leading to improved functional performance. Comparisons between the hatchlings and the adults led to the formation of a basic ethological model for venom spitting.

Keywords: ONTOGENY, ETHOLOGY, SNAKE, DEFENSIVE BEHAVIOUR