Abstract
Much of the foraging behaviour common to aquatic snakes may be associated with strategies that minimize encountered drag and forces of acceleration. By considering the various factors that contribute to drag, a single explanation emerges for the relative prevalence of crevice searching, mouth-open swimming, and lateral striking among aquatic snakes. These same factors contributing to drag also suggest that the paucity of aquatic vipers may be due to the poor hydrodynamic profile of the ‘typical’ viper head.