title: Hydrodynamic constraints on prey-capture performance in forward-striking snakes.
abstract: Some specialized aquatic snakes such as Natrix tessellata strike at fish by rapidly accelerating their head towards the prey with their mouth opened widely. This strategy is believed to be suboptimal as relatively high drag forces act on the open jaws and, therefore, probably limit strike speed. Moreover, the bow wave in front of the snake's jaws could push prey away from the mouth, thus potentially explaining the relatively low capture success observed in these animals (<20%). Here, we used laser-scan based computational fluid dynamics to test these potential constraints on prey-capture performance for N. tessellata. Our simulations showed that drag force indeed increases drastically for striking at a high gape angle. However, we estimated the overall cost in slowing down strike speed to be less pronounced due to the instationary dynamics of the system. In contrast to the expectations, forward displacement of prey was relatively limited (<13% of head length), and forceful collisions between prey and the leading edge of the jaw regularly occurred. However, our models showed that precise aiming by the snake was needed to reduce the chance of deviating the prey to a path bypassing the mouth. Our study also indicated several hydrodynamic advantages for snakes to strike at relatively large prey.
authors.affiliation: Department of Biology, Universiteit Antwerpen, Universiteitsplein 1, Antwerpen, Belgium. sam.vanwassenbergh@ua.ac.be
authors.forename: Sam
authors.initials: S
authors.lastname: Van Wassenbergh
authors.forename: Jonathan
authors.initials: J
authors.lastname: Brecko
authors.forename: Peter
authors.initials: P
authors.lastname: Aerts
authors.forename: Ilona
authors.initials: I
authors.lastname: Stouten
authors.forename: Gwen
authors.initials: G
authors.lastname: Vanheusden
authors.forename: Andy
authors.initials: A
authors.lastname: Camps
authors.forename: Raoul
authors.initials: R
authors.lastname: Van Damme
authors.forename: Anthony
authors.initials: A
authors.lastname: Herrel
mesh_terms: D000821:Animal Feed; D000818:Animals; D017812:Colubridae / Q000502:physiology*; D003198:Computer Simulation; D005247:Feeding Behavior; D007568:Jaw / Q000033:anatomy & histology / Q000502:physiology*; D008953:Models, Anatomic; D008954:Models, Biological; D011235:Predatory Behavior; D012984:Software; D013391:Sucking Behavior; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water