Triceratops were herbivorous, and because of their low slung head, their primary food was probably low growing vegetation, although they may have been able to knock down taller plants with their horns, beak, and bulk. The jaws were tipped with a deep, narrow beak, believed to have been better at grasping and plucking than biting.

Triceratops teeth were arranged in groups called batteries, of 36 to 40 tooth columns in each side of each jaw, with 3 to 5 stacked teeth per column, depending on the size of the animal. This gives a range of 432 to 800 teeth, of which only a fraction were in use at any given time (Tooth replacement was continuous throughout the life of the animal). They functioned by shearing in a vertical to near-vertical orientation. The great size and numerous teeth of Triceratops suggests that they ate large volumes of fibrous plant material, with some researchers suggesting palms and cycads, and others suggesting ferns, which then grew in prairies.
What was the Triceratops diet?
The triceratops were herbivores and are believed to have eaten plants such as palms, cycads and ferns.