Jumping mullet ― the internal diving bell hypothesis

Several lines of circumstantial evidence suggest that striped mullet, Mugil cephalus , use the upper posterior portion of the pharynx for aerial respiration, the air obtained either by jumping, rolling, or holding the head above the water and moving the air into the upper pharyngeal chamber. The principle evidence is that jumping frequencies are inversely correlated with dissolved oxygen concentration, and that the pharyngobranchial organ is capable of holding gas.