Page 20 - Eclipse - Autumn 2021

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Page 20 - Eclipse - Autumn 2021
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Computer simulations reveal dinosaurs

        wagged their tails when running





               cientists from the RVC       using two hind legs to move. This   and no tail at all, we were able to
               discovered that dinosaurs, like   included the modelling of a small   demonstrate that tail wagging was a
               Tyrannosaurus and Velociraptor,   carnivorous dinosaur, Coelophysis,   means of controlling angular momentum
        Swagged their tails when            a 210-million-year-old theropod,    throughout gait.ֱ
        running, similar to how humans swing   weighing around 15kg.            To ensure the reliability of their
        their arms when moving.
                                            By wagging from side to side, a bipedal   approach, the team simulated walking
        A team of researchers, led by the RVC,   dinosaurֱs tail was the main regulator of   and running in a modern theropod
        have uncovered a surprising functional   angular momentum, helping to dynamically  dinosaur, a South American tinamou
        similarity between dinosaur tails and   counterbalance the movement of   bird (Eudromia elegans, weighing about
        human arms, despite these structures   other body parts, like the hindlimbs.   500g). Simulations accurately replicated
        being separated by more than 300    Furthermore, when the tail was forced to   many important aspects of walking
        million years of evolution. The findings   wag out of sync with the hindlimbs, the   and running, as seen by comparing
        reveal that bipedal dinosaurs, like the   modelֱs energy budget greatly increased.   the results to previous experimental
        Tyrannosaurus and Velociraptor, wagged  Just like humans, this ֱcontrolֱ of angular   data for this species. Leg movement
        their tails from side to side when   momentum helps to make locomotion   patterns, footֱground forces, centre
        running ֱ similar to that of humans   more economical and stable.       of mass fluctuations and simulated
        swinging their arms back and forth   Previous studies have always       muscle activity patterns all agreed
        during movement. This ֱwaggingֱ was   treated non-avian dinosaur tails   reasonably well with the experimental
        to help angular momentum ֱ a principle   as a static, rear extension of the   data, bolstering confidence in the
        that dictates how ballerinas and figure   pelvis, acting as a counterbalance.   new methodology.
        skaters can execute pirouettes.
                                            However, this research moves beyond   Dr John Hutchinson, Professor of
        The study, published in Science     speculation of the tailֱs importance,   Evolutionary Biomechanics at the RVC
        Advances, was conducted by a team   and mechanically demonstrates a     and co-author of the study, further
        of palaeontologists, biomechanists   previously unrecognised, crucial and   added: ֱThese cutting-edge three-
        and engineers from the UK, Australia,   3D dynamic role.                dimensional simulations show that weֱve
        Belgium, and the US, and represents   Lead author Dr Peter Bishop, former   still got much to learn about dinosaurs.
        the culmination of over three yearsֱ   postdoctoral researcher at the RVC   Our results raise interesting questions
        work. Using sophisticated computer   (currently a research fellow at Harvard   about how dinosaur tails were used in
        simulations, and leveraging new     University, USA), commented: ֱI was   a whole array of behaviours, not just
        methods developed by engineers      very surprised when I first saw the   including locomotion, and how these
        working in medicine and aeronautics,   simulation results. After running a   functions evolved.ֱ
        the team assessed running           barrage of further simulations, including   Previous attempts at dynamic
        biomechanics in dinosaurs with tails,
                                            models with heavier tails, lighter tails   simulations of dinosaur behaviour























          Computer simulations of running locomotion in a modern tinamou bird (brown) and extinct theropod dinosaur Coelophysis (green)
          Image credit: Peter Bishop

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