Stegosaurs have in the past been presented to us as lumbering plant eaters, but in reality they were lethal fighters when necessary, according to palaeontologists who have unveiled new evidence of a casualty of stegosaurian combat. The evidence is a fatal stab would in the pubis bone of a predatory allosaur. The wound – in the conical shape of a stegosaur tail spike – would have required a great dexterity to inflict and demonstrates clear signs of having fatally wounded the allosaur.
“A massive infection ate away a baseball-sized sector of the bone,” reports Houston Museum of Natural Science palaeontologist Robert Bakker and his colleagues, who presented a poster of the discovery on Tuesday at the meeting of the Geological Society of America in Vancouver, B.C. “Probably this infection spread upwards into the soft tissue attached here, the thigh muscles and adjacent intestines and reproductive organs.” The lack of evidence of healing strongly implies that the allosaur died as a result of the infection.
Similar wounds are seen in rodeo cowboys or horses when they are gorged by longhorns, Bakker said. And since like large herbivores – like longhorn cattle, rhinos and buffalo – today use horns as defensive weapons, its reasonable to assume spiky herbivorous dinosaurs did the same. A big difference is that stegosaurs wielded their weapon on their tails rather than their heads. Skeletal evidence from fossil stegosaurs suggest their tails were much more dexterous than most other dinosaur tails.
“They have no locking joints, even in the tail,” Bakker explained. “Most dinosaurs tails get stiffer toward s the end.” However, stegosaurs had huge muscles at the base of the tails, flexibility and fine muscle control all the way to the tail tip. “The joints of a stegosaur tail look like a monkey’s tail. They were built for 3-dimensional combat.”
In order to inflict the mortal wound to the allosaur, a stegosaur would have had to sweep its tail under the allosaur and twist the tail tip, because usually the spikes point outward and backward. That would have definitely been within the ability of the stegosaur, Bakker said.
The fighting style and skill of stegosaurs will come as no surprise to those familiar with the dinosaur battle scene in the 1940 Disney animated film Fantasia, said Bakker. That section of the movie displays a beefed up allosaur attacking a stegosaur. The stegosaur delivers a number of aimed tail blows at the predator, but ends up losing the fight. The Fantasia stegosaur tail dexterity appears to be accurate, he said. However, he questions the stegosaur’s loss at the end. “I think the stegosaur threw the fight,” he said. On the other hand, he points out stegosaurs had among the smallest brains for its body size of any large animal, ever.
Contributing Source: The Geological Society of America
Header Image Source: WikiPedia