Moss Landing Marine Laboratories
The Delphinidae Family of odontocete cetaceans includes about 30 species of small (< 4 m long) toothed whales generally termed dolphins, and four species of larger (4 to 6 m long) toothed whales. The smaller members of the family include the bottlenose dolphin, Tursiops truncatus, the common dolphin, Delphinus delphis, and several species of the genera Lagenorhynchus and Stenella. The larger members include the killer whale, Orcinus orca, and the pilot whales, Globicephala sp. ( Leatherwood, Reeves, & Foster, 1983). The family is therefore represented by a large and relatively diverse group of mammals, having different modes of living and probably several different social systems as well. A brief review such as this can only provide examples of the better known feeding strategies of a few species, and I wish to emphasize that I make no attempt at an exhaustive survey of the family. It will become apparent, I hope, that some species have quite variable feeding behaviors, and some feed in complex cooperative ways which we are only beginning to understand.
Most delphinids are social mammals that almost always carry out their activities within the security and efficiency of a school of variable size (reviews by Norris & Dohl 1980a; Wells, Irvine, & Scott, 1980, Gaskin, 1982). Although schooling has many potential advantages, the primary ones for most species are presumably reduced predation and enhanced efficiency of finding and securing prey. Schools of dolphins--like other mammalian social units, but perhaps unlike most schooling fishes, invertebrates, and flocking birds--are composed of complexly interacting individuals, some of whom are likely to know each other, have preferred social and sexual partners, and often travel in long-term