Calcarisaurus (Calcarisaurus ieiuniosus, meaning Hungry Spur-lizard), measure 5-7 feet in length.
The Moloch-like Calcarisaurus was a small, thorny reptile with a near impregnable hide. Despite its small size, few predators bothered the plucky little tank out of respect for its battery of spurs, which covered almost every surface of its body. A secreted irritant along the edges of Calcarisaurus' spurs helped to drive home its message of inedibility to the curious or stupid.
Such a solid defense granted Calcarisaurus impunity to wander the island without fear of molestation by carnivores. As a result, its eyesight and hearing were poor, having little need for those senses to alert it to danger.
Smell was Calcarisuarus' principal sense and it was used to track down small lizards, rodents, and large invertebrates in the scrub and open regions. Centipedes were a particularly favored prey and were excavated from their burrows by Calcarisaurus with its strong digging claws. The bites of the large Skull Island centipedes did not worry the animal.
One predator alone was a threat to Calcarisaurus. Venatosaurus, intelligent and adaptable, had developed strategies for flipping its prey to expose the vulnerable, less heavily armored underside, restricting Calcarisaurus to regions where the predators seldom roamed.