Stegosaurus Week: The Weak Bite of Stegosaurus

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In discussions of dinosaur bite mechanics, the heavy forces generated by predatory species often dominate, but it is important to understand how the jaws of herbivores worked, too. The jaws of Stegosaurus might not be as immediately impressive as those of Tyrannosaurus rex, but it is still important to know how they were put to use if we are to understand the paleobiology of the famous armored dinosaur. Now, thanks to computer models created by Miriam Reichel, we can better understand what Stegosaurus was capable of eating.

The teeth of Stegosaurus are almost all the same: a series of rounded, minutely-ridged teeth arranged in straight rows from front to back. To investigate how this dental arrangement would have worked while consuming food, Reichel created 3-D models of the teeth (both with ridges and without) to create a virtual model of Stegosaurus jaws. This digital dinosaur was then set to work on computer-generated cylinders given the properties of different types of plant food, using the muscle attachments seen on the dinosaur's skull to determine how hard its bite would have been.

As calculated by Reichel, Stegosaurus didn't have a very powerful bite. Even you and I could bite harder than Stegosaurus. The dinosaur could generate enough force to crunch through twigs and branches under a half an inch in diameter, but anything bigger than that and it would have a difficult time of it. Given its weak jaws, Stegosaurus would have had to rely on soft, fast-growing plants; it is fantastic to think that this large dinosaur could have survived on such a diet!

Then there is the matter of the actual method by which Stegosaurus processed its food. It probably did not chew its food to any great degree, but instead sliced through soft plants before swallowing. Additionally, Reichel proposes that Stegosaurus may have had a tough beak at the front of its jaws which took most of the punishment during feeding. The teeth were left with the lighter work, although, since Stegosaurus jaws were weakest at the front, this might mean that it was only eating the softest, greenest food available. Further study will be required to understand the precise mechanics of how Stegosaurus ate, but, at the very least, Reichel's work confirms that this dinosaur had to carefully pick out soft Jurassic salads for lunch.

Reichel, M. (2010). A model for the bite mechanics in the herbivorous dinosaur Stegosaurus (Ornithischia, Stegosauridae) Swiss Journal of Geosciences DOI: 10.1007/s00015-010-0025-1

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