In The Good Dinosaur , the main character Arlo is an Apatosaurus , a long-necked herbivorous sauropod dinosaur.

Arlo’s Dinosaur Type

  • Arlo and his family are explicitly described as Apatosaurus farmers in the film’s story and production notes.
  • Apatosaurus is a large, long-necked, four-legged sauropod that lived in the Late Jurassic period, and Arlo’s design follows this classic sauropod body shape.

How The Film Portrays Him

  • The movie imagines a world where dinosaurs never went extinct and evolved into more “human-like” roles, so Arlo’s Apatosaurus family works as crop farmers.
  • His timid, youthful personality and slightly stylized proportions were chosen so audiences could see the “boy” inside the dinosaur, even though he is an Apatosaurus.

TL;DR: The Good Dinosaur (Arlo) is an Apatosaurus, a long‑necked sauropod.