National Geographic : 2008 Sep
Like wolves on a caribou herd, sailfish cooperate sometimes for several hours-to turn unwieldy prey into a manageable meal. The predators shoot in from all sides, popping open fins and flashing iridescent colors as they get up close. "It's like saying, Boo! I'm here!" says marine scientist Guy Harvey, a longtime sailfish observer. "There's a shock effect that pushes prey together." Once a ball is under control, the sailfish take turns shooting through it, heads whipping side to side as they use their bills to bat sardines (center) with remarkable precision. Pursuers then nab stunned fish before they can escape. Whittled down to its last bloody stragglers, the ball spins in a slow vortex (bottom), prey exhausted and no longer in perfect concert. Typically sailfish will consume every last one. It Feeding Frenzy Watch sailfish make short work of a sardine ball at ngm.com.