Dinosaur Feeding

Abstract

Many dinosaurs can be relatively easily partitioned, on the basis of their tooth morphology and skeletal form, into those that were classically sharp‐toothed, agile and fast‐moving carnivorous theropods such as Coelophysis , Velociraptor and Tyrannosaurus . Alternatively others had comparatively blunt teeth, were rather heavy‐legged and barrel‐bodied herbivorous sauropodomorphs, for example, Diplodocus , cerapods, for example, Triceratops and armoured thyreophorans, for example, Sauropelta . However, some dinosaurs, as we shall see (e.g. heterodontosaurs, therizinosaurs, alvarezsaurs and spinosaurs) exhibit anatomies that cannot be so readily categorised; these challenge our understanding of likely feeding behaviours. For these latter creatures a more comparative–deductive approach must be adopted. Detailed investigation of such ‘atypical’ types, as well as the more classic morphologies, suggests that some dinosaurs exploited morpho‐functional solutions to the problems posed by feeding that are not seen among present‐day animals. Key Concepts: Tooth morphology provides direct information about the potential diets of long‐extinct animals. Skeletal morphology provides information about the mechanics and potential lifestyle of long‐extinct animals. Morphology and lifestyle interpretations based on dinosaur skeletons contain information that is relevant to deductions concerning their probable diets. Jaw mechanics and tooth wear patterns provide objective information about bite forces and the movement of food caught between the teeth. Carnivores typically eat meat and have predatory habits, but such animals are not exclusively predatory because today many are also known to take carrion opportunistically. Herbivores typically eat plant material, but some classically herbivorous reptiles (such as land iguanas) are also known to eat eggs, young mammals or chicks, as well as carrion; these considerations also apply to animals such as rodents. So such apparently clear cut human definitions are evidently not as clear in real life. Finite Element Modelling and Beam Theory have been used to augment information about the range of feeding styles in dinosaurs. Pleurokinesis is a cranial mechanism that allows classically reptilian herbivores (i.e. ornithopod dinosaurs) to develop a power stroke, during jaw closure, by mobilising the lateral walls of the skull. This enables oral processing (repetitive chewing) of plant material. Co‐evolutionary relationships (between dinosaurs and plants) in the fossil record, notably with respect to the coincident timing of the evolution of angiosperms (flowering plants) and diversification of herbivorous dinosaurs, cannot be proved.