By james art From beetles to birds and everything in between, sight is one of the most important senses in an animal’s toolkit, so understanding how they use it can tell us a lot about their biology, behavior and role in their ecosystem. Unfortunately, such understanding becomes unclear for extinct animals such as dinosaurs, as fossils simply do not preserve most of the soft tissues associated with vision.
However, a recent study published in the Journal of Vertebrate Palaeontology has shed new light on how dinosaurs and their relatives saw the world. In living animals, the sense of sight is often tied to how big the eye is—a larger eye equals better vision—so disentangling dinosaur vision becomes a matter of determining eye size. In birds and crocodiles, the dinosaurs’ closest living relatives, the ratio between the size of the orbit (eye socket) and the size of the eye increased at a reliable rate. Therefore, by measuring the length of the dinosaurs’ orbits, it is possible to predict how large their eyes may have been.
Using existing data from the scientific literature, skull length and orbital diameter were measured in 400 species of archosauromorphs, the main group of reptiles that includes dinosaurs, pterosaurs, crocodiles and their closest relatives. This was carried out by a group of 22 palaeontology students from the University of Birmingham, giving students the opportunity to contribute to research that they might not otherwise receive until later in their careers. Each student was assigned a group or clade of about 20-35 species to study. They then used these measurements to calculate how large the eye might have been in each species. As well as being included in this study, each student’s collected data was also used for a personal research assignment as part of their undergraduate course.