The mechanism is suction feeding, and the matamata is one of its more extreme practitioners. Muscles pull the hyoid apparatus down and back, expanding the mouth and throat cavity abruptly. Water rushes in to fill the space, carrying the prey with it. The strike takes on the order of a hundredth of a second, and the water is then expelled through the partly closed jaws while the fish is retained.
The jaws themselves are weak and the head is broad and flat, shaped for volume rather than force. Everything about the animal supports getting close enough for the vacuum to work: fringed skin flaps and a warty shell break its outline in leaf litter, and it approaches prey with slow head movements.
The snout, often described as a snorkel, allows breathing without lifting the head clear of the surface.