Although human in appearance, this species of primitive people are in fact a spin-off of Paranthropus Robustus (also called Australopithecus Robustus), which existed up until 1.2 million years ago. While Paranthropus Robustus were more gorilla in bone structure, this primal culture had evolved to be more human-like in build but with a great deal more hair in the males. The females, oddly enough, did not exhibit this same trait and were generally hairless outside of their head area.

Living in the lost world found in the North Pole, the primal species enjoyed a lush, tropical climate zone that was created by a nearby volcano. The abnormal weather permitted a mix of dinosaurs and mammals, such a rabbits which were a common meal choice for both, to thrive.

When the crew of the Polar-Borer arrived at the hidden world, the primal men initially refrained from contact, following them far enough behind to avoid detection and would investigate anything they dropped. After the tyrannosaurus rex destroyed the Polar-Borer camp and hid the ship, the primitive species started to get more brave and also aggressive. The species, which must have thrived more on gathering, had never learned how to develop spears until they witnessed the crew of the Polar-Borer doing so and then adapted this as a weapon of their own. The primal men became increasingly confrontational as well, fighting off the stranded crew of the Polar-Borer for food. This peeked into a full-on near attack, that was thwarted when Masten Thrust of the Polar-Borer crew used a recently created crossbow to kill the leader of the primal men, sending them into retreating and causing them to leave the crew alone.

One member of the primal group had a different outlook on the Polar-Borer crew, however. Given the name Hazel by the crew, she attempted to follow them and later joined the group until she was evicted toward the end as Masten Thrust became more obsessed with destroying the tyrannosaurus rex.