Wednesday, January 20, 2010

Feeding


        Various methods of feeding exist among and within species, some apparently exclusive to a single population. Fish and squid are the main food, but the False Killer Whale and the Killer Whale also feed on other marine mammals.

        One common feeding method is herding, where a pod squeezes a school of fish into a small volume, known as a bait ball. Individual members then take turns plowing through the ball, feeding on the stunned fish. Coralling is a method where dolphins chase fish into shallow water to more easily catch them. In South Carolina, the Atlantic Bottlenose Dolphin takes this further with strand feeding, driving prey onto mud banks for easy access. In some places, Orcas come to the beach to capture sea lions. Some species also whack fish with their fluke, stunning them and sometimes knocking them out of the water.

        Reports of cooperative human-dolphin fishing date back to the ancient Roman author and natural philosopher Pliny the Elder. A modern human-dolphin partnership currently operates in Laguna, Santa Catarina, Brazil. Here, dolphins drive fish towards fishermen waiting along the shore and signal the men to cast their nets. The dolphins’ reward is the fish that escape the nets.