Porter, H.T.*; Motta, P.J.: A Comparison of Prey Capture Behavior and Kinematics in Three Ram Feeding Fishes

Ram feeding is the process by which a predatory fish uses a high-velocity lunge or chase to overtake its prey. This study compares the strike and prey capture behaviors and kinematics of three species of ram-feeding fishes: Florida gar Lepisosteus platyrhincus, redfin needlefish Strongylura notata, and great barracuda Sphyraena barracuda. These ram-feeding piscivores are morphologically similar with fusiform bodies, posteriorly-placed dorsal and anal fins, and large, conical teeth. Strike and prey capture behaviors and kinematics for five individuals of each species were recorded with high-speed video. Pre-strike behavior in gar consists of a slow stalk, resulting in the close, lateral positioning of the predator’s head relative to the prey. Gar employ a sideways lunge of the head during the strike, which lasts only 25 to 40 milliseconds. Needlefish and barracuda exhibit longitudinal orientation to the prey before the strike, followed by a high velocity, head-on lunge initiated by an s-start. Needlefish and barracuda achieve average strike velocities of 64 cm/s and 144 cm/s respectively. Prey capture in gar and needlefish is characterized by the jaws closing on the prey, which is generally positioned orthogonal to the jaws. This is followed by manipulation to reposition the prey head first, and suction transport into the buccal cavity. Manipulation can last up to 7000 milliseconds. Prey capture in barracuda is accomplished by closing the jaws after the prey has entered the buccal cavity, resulting in ram transport of the prey with no oral manipulation. The differences among these species in kinematics may be related to differences in cranial morphology, size, and habitat-specific behaviors.