Figure 1. (a) Suction feeding mechanism in the sturgeon is a highly protrusible mouth that extends downward to vacuum up sediments containing clams and other prey. (b–e) Suction feeding in a piscivorous wrasse feeding on a small fish (grid, 1 cm). This behaviour is characterized by rapid jaw opening (b–d = 25 ms), suction (d) and jaw protrusion during mouth closing (e).

Figure 2. Jaws of fishes specialized for feeding by biting. (a) The jaw of a lemon shark with numerous rows of replaceable teeth. (b) The skull of a large parrotfish with beak-like jaws that are used for scraping algae from surfaces of coral reefs. (c) The extreme canine teeth of the vampire characin are used for impaling small fishes before swallowing. (d) The sturdy cutting jaws of the piranha enable this fish to bite off fins and remove pieces of meat from prey. All specimens are from the Field Museum of Natural History collections. Bar, 5 cm.

Figure 3. The sling-jaw wrasse Epibulus insidiator is the champion of jaw protrusion in fishes. Three frames from a high-speed film (total duration 0.03 s) of the feeding strike show that Epibulus can protrude its jaws forward by 65% of its head length. Adapted from Westneat (1991). Grid, 1 cm.

Figure 4. Phylogeny of major groups of fishes, with a historical perspective on the major evolutionary trends in the structure and function of feeding.