In the first description of "Trilophosuchus", Paul Willis tentatively considered the genus to be terrestrial, because most other extinct crocodyliforms with short snouts and laterally directed eyes were terrestrial. The arrangements of the neck muscles of "Trilophosuchus", evidenced by the shape of the occipital portion of the skull, suggests that it held its head high, a posture more suitable for a terrestrial rather than semiaquatic lifestyle. Compared to living animals, "Trilophosuchus" probably had a posture more like monitor lizards than crocodiles. The short length of its snout, contrasting with the longer snouts of larger carnivorous crocodylians such as "Pristichampsus", suggests that "Trilophosuchus" restricted its diet to smaller prey. It may have consumed fish, turtles, snakes, and small mammals, all of which have been found from Riversleigh. The neck musculature of "Trilophosuchus" may have enabled it to make rapid movements of the head when feeding, up and down, side to side, and rotationally.