A new analysis of ostriches reveals that a computer model of long-necked sauropods used to simulate the dinosaurs' movements, featured in BBC's Walking with Dinosaurs and the focus of an installation at the American Museum of Natural History, New York, does not correctly reconstruct how flexible their necks were. The results are published August 14 in the open access journal PLOS ONE by Matthew Cobley from the University of Utah, with colleagues from the University of Bristol and Natural History Museum, London.
Previous estimates of sauropod neck flexibility were based on the positions of neck vertebrae, but this new research suggests these estimates were probably inaccurate, as the models don't account for the effects of soft tissues like muscle and cartilage. This analysis of ostriches, close relatives of the long-necked sauropod dinosaurs, reveals that increasing muscle mass in the neck reduces the maximum flexibility of their necks. Variations in the distance between vertebral joints and the amount of cartilage present in the neck could also have reduced the flexibility of sauropods' long necks, according to this research.
Museum exhibits and movies often depict sauropods arching their necks into a wide range of movements, all the way from tree-tops to low vegetation. However, the results of this study indicate that these dinosaurs may have been less flexible than typically depicted. Having less flexible necks would have likely restricted the range of foods these dinosaurs could reach, their ecological niches, and consequently, they may have foraged more actively to meet their average dietary needs of approximately 400 kg of plant matter each day.
Cobley adds, "I believe the most important thing to take away from this study is that computer modeling of any biological system – be it anything from an individual organ to a whole dinosaur - needs to be 'ground-truthed' before it is accepted by the scientific community and presented to the public. It's easy to be swayed by these beautifully reconstructed models of dinosaurs, but if these models aren't based on real, empirical data taken from living animals we can actually study, they only serve to confuse the general public."
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More information: Cobley MJ, Rayfield EJ, Barrett PM (2013) Inter-Vertebral Flexibility of the Ostrich Neck: Implications for Estimating Sauropod Neck Flexibility. PLoS ONE 8(8): e72187. DOI: 10.1371/journal.pone.0072187