Dueling Dinosaurs: Stegosaur Stabbed Predatory Allosaur to Death with Deadly Tail Spike

The stegosaur may have been a herbivore, but it was no pushover in a fight. New evidence reveals that a predatory allosaur was stabbed to death by a stegosaurus, showing that this dinosaur wasn't one to think lightly of.

In this case, the researchers uncovered the fossil of an allosaur that died from a fatal stab wound in its pubis bone. This stab wound, in particular, was in the conical shape of a stegosaur tail spike. The stegosaurus that created this wound had to have had precise aim and dexterity in order to hit its target.

"A massive infection ate away a baseball-sized sector of the bone," said Robert Bakker, one of the researchers, in a news release. "Probably this infection spread upwards into the soft tissue attached here, the thigh muscles and adjacent intestines and reproductive organs."

In fact, it's likely that the allosaur probably died from the infection rather than the initial stab wound. That said, the spikes on the stegosaurus were probably used to defend itself; like the herbivorous longhorns, rhinos and buffalo of today, the stegosaur used its spikes as defense. The only difference was that these spikes were located on the stegosaurs' tail.

"They have no locking joints, even in the tail," said Bakker. "Most dinosaur tails get stiffer towards the end. The joins of a stegosaur tail look like a monkey's tail. They were built for 3-dimensional combat."

It's likely that to deal the fatal wound to the allosaur, the stegosaur would have had to sweep its tail under the allosaur and then twist the tail tip, since normally the spikes point outward and backward. Due to the tail's flexibility, this would have been entirely possible.

The findings reveal a bit more about dinosaur behavior, and show that even herbivores were not to be trifled with.

The findings were presented at the meeting of the Geological Society of America in Vancouver, B.C.