When sucking up small prey, many fishes look like they’re sticking their lips out. This kiss-of-death gesture — actually done by mobile upper- and lower-jaw bones — dramatically increases the fish’s suction power, researchers have now found, lowering the prey’s chances of escape.
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The results may help explain the evolutionary advantage of the diverse types of extendable jaws sported by as many as half of all fish species. “From this work, it is clear that the success of a prey-capture event could strongly depend on the ability of a fish to protrude its jaws,” comments Timothy Higham of HarvardUniversity.
Peter Wainwright of the University of California, Davis and his collaborators fed live ghost shrimp to bluegills (Lepomis macrochirus) in a lab tank and recorded the fish’s chomps at 500 frames per second. At the same time, the team scattered laser light off particles suspended in the water. Researchers then used computer software to track the motion of the fish, the prey and the particles in the surrounding water. From that, the team was able to measure the forces exerted on the shrimp.