Where the digestive system was suffocatingly humid, the respiratory system was a domain of fierce winds and unpredictable currents. In the dinosaur’s lungs, the ants witnessed the awe-inducing sight of air dissolving into the bloodstream via the vast three-dimensional labyrinth formed by the air sacs. That river of blood, flowing from some unknown source, alerted them to the existence of other worlds inside the dinosaurs, worlds that they would much later come to identify as the circulatory system, the nervous system and the endocrine system.

The focus of the third stage of exploration was the dinosaurs’ craniums. On their first attempt, the ants ventured in through their subject’s nostrils. Light-footed though they were, their pattering caused such intense tickling that the dinosaur sneezed with tornadic ferocity, shooting the little prospectors back out of its nasal passageway like bullets from a gun. Most of the team members on that initial mission were torn to shreds. Later cranial survey expeditions entered through the ears, with more success. En route, they investigated the dinosaurs’ visual and auditory organs and analysed those delicate systems. They did eventually manage to reach the brain, though it was many years before they worked out the purpose and significance of that most mysterious of organs.

And so it was that the ants gained a detailed understanding of dinosaur anatomy, laying the foundations for the medical revolution that followed.

Ant expeditions often entered the bodies of sick dinosaurs – massive creatures that had been reduced to skin and bone, their eyes dull and heavy, their movements slow and feeble, creatures that could do little but continually moan with pain. By comparing their interior systems with those of healthy dinosaurs, the ant explorers were easily able to pinpoint the locations of the diseased organ or lesion in question. They envisioned many different methods of treating internal diseases in dinosaurs, but not a single one could be put to the test, for such mammoth undertakings would require the consent of the dinosaur itself and to date the ants had always gained access without their hosts’ knowledge.

The vast majority of dinosaurs would on no account let the ants burrow into their stomachs or brains, even if their intentions were entirely honourable and therapeutic. However, an epoch-making breakthrough occurred in this regard with a Hadrosaurus named Alija, the earliest named dinosaur in the history of Cretaceous civilisation.