June 17th, 2015
Remember Jurassic Park? Remember those stately long-necked dinosaurs (aka sauropods)? Necks graciously curved to reach the top leaves of the giant trees, the flexibility of their necks seems to rival that of modern swans.
But were these mighty beasts capable of holding their necks in that position? Currently, there are three main hypotheses: (1) low flexibility, suggesting that these long-necked dinosaurs held their necks in a downward slope, (2) high flexibility, think Jurassic Park-like feeding, and (3) medium flexibility, proposing that their necks could be held a bit above the horizontal plane and moved sideways to a reasonable degree.
These hypotheses are based on a variety of study methods, from investigating the neck flexibility of present-day long-necked creatures to constructing 3D computer models of fossil vertebrae. However, all this previous work is based on bones and their mechanics alone. But necks are more than that. There’s a lot of soft tissue as well. Might that affect neck flexibility?
To answer this question, a new study in PLOS ONE takes a look at the effect of soft tissue and cartilage on ostrich neck flexibility.
(Interlude: Why an ostrich? Well, firstly, and obviously, ostriches have long necks. But also, ostriches, like all birds, are, evolutionarily speaking, a group of living dinosaurs! Just think of that next time you’re eating chicken.)
Back to the study. Using three necks and heads of deceased ostriches (Struthio camelus for those of you who like Latin), the flexibility was determined during different stages of tissue removal. In other words, the researchers, from the University of Bristol and the Natural History Museum in London, removed one muscle group at a time and measured the flexibility after each removal. Also, measurements were taken with wet cartilage, dry cartilage and after removing the cartilage.
So, what did they find?
First of all, the ostrich neck can be divided into three regions with different flexibility: a less ‘bendy’ area near the head, then a more flexible region, and a stiffly linked collection of a few vertebrae near the body.
And, secondly, as more muscle and cartilage was removed, the flexibility increased. So the muscle and cartilage limit the neck flexibility.
This means that previous work on sauropod necks and feeding, which, remember, was based solely on the bones, might, at times, overestimate the neck bending options of these extinct giants, which, in turn, has serious potential implications for their feeding abilities. And for the scientific accuracy of Jurassic Park…
Cobley, M.J.; Rayfield, E.J. & Barrett, P.M. (2013). Inter-Vertebral Flexibility of the Ostrich Neck: Implications for Estimating Sauropod Neck Flexibility PLOS ONE DOI: 10.1371/journal.pone.0072187
sauropod evolution, dino with long neck