Meeting Abstract

10.5  Sunday, Jan. 4  Hydrodynamics of prey capture in forward striking piscivorous snakes VAN WASSENBERGH, S.*; BRECKO, J.; HERREL, A.; VAN DAMME, R.; AERTS, P.; Univ. Antwerpen, Belgium; Univ. Antwerpen, Belgium; Univ. Antwerpen, Belgium; Univ. Antwerpen, Belgium; Univ. Antwerpen, Belgium sam.vanwassenbergh@ua.ac.be

Aquatic snakes generally use fast, frontally directed strikes to capture prey under water. The prey is typically approached with a relatively wide gape, without making use of suction. A potential problem with this mode of prey capture is the generation of bow waves that tend to push prey away from the rapidly approaching, open-mouthed snake. However, the magnitude and importance of bow-wave effect for feeding performance remains unknown. Here we studied the hydrodynamics of forward striking in a specialist fish-eating species Natrix tessallata by means of computational fluid dynamics (CFD). To do so, 3D laser scans of preserved specimens were made and a finite volume mesh was created and imported into Fluent software. Flow patterns and hydrodynamic effects on a spheroid-shaped prey approached by the snake model at steady speeds, and at constant accelerations were studied for a range of different gape angles. Our results show that pushing of the prey occurs, but is generally restricted to the zone in between the jaws of the snake. A larger gape does not result in increased pushing of the prey, but strongly increases the drag to be overcome by the snakes locomotion system to reach a given approaching speed. The effect of different strike kinematics and mouth opening and closing will be discussed as well.