Wise old bird

摘要

The speculation, in an article on the evolution of our brains, that a dinosaur or bird could have evolved considerable intelligence instead of us was engaging (24 September, p 40). I suggest another candidate: the dinosaurs' other flying cousins, pterosaurs, which had a high brain-to-bodysize ratio compared with dinosaurs.Birds that colonise isolated islands sometimes become flightless. The same could have happened to pterosaurs. They had three functional digits on the front of each wing, which may not have been useless if they became flightless. Fossilised tracks show that pterosaurs walked on all fours.