Carousel feeding is a cooperative hunting method used by Norwegian orcas (Orcinus orca) to capture wintering Norwegian spring-spawning herring (Clupea harengus). The term carousel feeding was first used to describe a similar hunting behaviour in bottlenose dolphins (Turslops truncatus) in the Black Sea. There are two main phases of carousel feeding in orcas, the herding phase and the feeding phase. In the herding phase the orcas surround a school of herring and herd them into a tight ball. They tighten the ball by blowing bubbles, flashing their white underside and slapping their tails on the surface. They move the ball of herring toward the surface of the water before initiating the feeding phase. During the feeding phase several orcas begin to eat while the others continue herding the fi