You don’t need to be a palaeontologist to guess that Stegasaurus’ tail spikes were not just for decoration. But on Tuesday, scientists from the Houston Museum of Natural Science revealed that they have discovered evidence suggesting this herbivorous dinosaur could have been deadly in combat when necessary.
A predatory allosaur has been discovered with a fatal stab wound through its pubis bone, an injury that matches the conical shape of a Stegosaurus tail spike. Although it isn’t unusual to see this kind of defensive behaviour in herbivores – just think of rhinos, bulls or buffalos –what is remarkable is the sheer dexterity and strength that would have been required to inflict this kind of injury. The remaining bone shows a large chunk of tissue that appears to have been eaten away. This, coupled with a lack of evidence indicating any healing, suggests that a consequent infection caused the death of the predator, 147 million years ago.
Skeletal evidence supports the belief that Stegosaurus had particularly flexible tails. Robert Bakker, a palaeontologist from the museum involved in the discovery, explained: ‘they have no locking joints, even in the tail. Most dinosaur tails get stiffer towards the end.’ Complimenting this flexibility were massive muscles at the hips, with muscle attachments continuing all the way to the tip, giving full 3-dimensional control. As the spikes on the tail point outward and backward, the wound would have had to be delivered by a twisted sweep up and under the allosaur – a movement that the animal would have been more than capable of. Classically, Stegosaurus has been portrayed as a slow, lumbering beast. This new discovery shows us that perhaps that isn’t such a fair description after all.