Amphibian metamorphosis often involves terrestrialization with associated changes that exemplify adaptations necessary for land invasion, which Devonian proto-tetrapods must have negotiated. Underwater, fish often utilize suction feeding, exploiting water’s hydrodynamic properties to transport food within the mouth. By contrast, air-based feeding requires direct tongue-based food manipulation. In both water and air, the tongue is an important component of the feeding apparatus, but our understanding of mechanical adaptations of tongues across terrestrialization is poor. Using ambystomatid salamanders, we investigate tongue movement with respect to the jaw and the food during feeding. Subjects and their food items are implanted with radiopaque markers that are tracked via video-fluoroscopy. We hypothesize that there is a decoupling of food and tongue motion as aquatic tongues retract and depress during gape opening. By contrast, in air, we hypothesize that tongues elevate and protract as the mouth opens in synchrony with food motion, as seen in lepidosaurs and mammals. We use tongue, food, and jaw motion loops to show that, during aquatic food processing, onset of food motion lags approximately 18% from onset of tongue motion, with a near-zero lag in air. Further, using a 3D skull reference coordinate system, we show that aquatic tongues retract and depress as the mouth opens, while terrestrial tongues translate in the opposite direction along each plane. Thus, the timing and nature of tongue-based food control changes profoundly as ambystomatids terrestrialize, supporting our hypotheses of an ancestral hydrodynamic-tongue system for aquatic feeding being substantially altered across terrestrialization. Our results illustrate some overlooked challenges that proto-tetrapods negotiated as they invaded land.