Dinosaur Locomotion
Authors: Bates Karl T 
Published: April 2013

Abstract

The skeletons of dinosaurs, particularly large‐bodied, enigmatic forms like
Tyrannosaurus
and
Triceratops
, are awe inspiring and have been brought ‘back‐to‐life’ in numerous animated and motion picture productions. But how did these animals really stand and move in life and how rigorously can scientists reconstruct their locomotion? In recent years, traditional approaches, such as morphological comparisons and limb bone scaling, have been combined with new computational modelling methods to provide rich insight into dinosaur locomotion and how it may have changed during the group's long evolutionary history. However, many significant challenges remain and currently it is still difficult to constrain how any one dinosaur moved. Unknown factors, such as body mass and muscle anatomy, make it difficult to reliably reconstruct the motions and capabilities (e.g. running speeds) of dinosaurs based on data available from fossils. Thus, future work must continue to integrate information on dinosaur anatomy with principles of locomotion established in living animals, as well as embracing a range of methodological approaches.

Key concepts:

Dinosaurs represent a unique and interesting system for studying adaptation and locomotion due to their diverse morphologies, body sizes and changes in posture during their long evolutionary history.

It is difficult to constrain how dinosaurs moved because there are so many unknown factors such as their body mass and muscle anatomy.

Fossil skeletons and footprints reveal that dinosaurs used an ‘erect posture’ and restricted most limb movements to a plane parallel to the body (parasagittal gait).

Comparative anatomy and limb bone scaling allows general comparisons between locomotion in dinosaurs and living mammals and, for example, suggests both predominantly drove limb motion from the hip (versus the knee and ankle in birds).

Computer modelling approaches are becoming widely used to investigate dinosaur locomotion and biomechanics in extinct animals in general.

Computer modelling approaches allow the role of individual muscles in dinosaur limbs to be investigated, and thus it is possible to compare how muscles might have functioned in dinosaurs and their closest relatives (in other words to investigate how muscle function evolved).

Biomechanical models and computer simulations have been used to investigate how dinosaurs might have moved and what kind of locomotor behaviours they might have been capable of (e.g. running ability).

Biomechanical approaches require explicit specification of muscle properties for dinosaurs. Because most if not all of these parameters are unknown for dinosaurs, and in many cases only broadly estimable, researchers have used sensitivity analysis to quantify the potential margin of error in their predictions. This results in a broad range of predicted running gaits and top speeds for dinosaurs.

To address these challenges and better understand dinosaur locomotion, future work must be highly integrative, combining methods and evidence from anatomy, trackways and biomechanical modelling with better understanding of locomotion in living animals.