Abstract
Traditionally sperm whales (Physeteridae), beaked whales (Ziphiidae) and beluga (Monodontidae) are known as “suction feeder”, but the use of suction force by the other dolphins has become known recently.
To know the suction feeding mechanisms in the dolphins, we investigated suction feeding behavior of a captive Indo-Pacific bottlenose dolphin (Tursiops aduncus) by direct observation and dissected the finless porpoise (Neophocaena phocaenoides) stranded on beach to clarify the structure of gular musculature.
Our observations indicate that Trusiops and Neophocaena are suction feeder with weak suction force and different from traditional strong suction feeder. It is said that the strong suction feeding is achieved by combination of tongue retraction and mouth floor distention, and used to intake prey into the mouth. While we proposed that the weak suction feeding is achieved by expansion of the posterior oral cavity during anterior stabilization of the tongue, and used mainly to transport a prey to the digestive tract after it is taken in the mouth.
