So quantum compasses are probably ancient, and are likely to have provided navigational skills for the reptiles and dinosaurs that roamed the Cretaceous swamps alongside the T. rex we met in chapter 3 (remember that modern birds such as robins are descended from dinosaurs), the fish that swam the Permian seas, the ancient arthropods that crawled over or burrowed beneath the Cambrian oceans and maybe even the pre-Cambrian microbes that were the ancestors of all cellular life.
