Stegosaurs Dole Out Lethal Strikes When Necessary

The stegosaurs might have seemed like a passive, lumbering plant eater, but new research shows that it doled out lethal strikes when necessary.

This is according to paleontologists who have uncovered new evidence of a casualty sustained during combat with a spiky stegosaur. The victim in question was a predatory allosaur, a big, mean, killing machine that reigned supreme during the late Jurassic period, according to BBC Nature. Even weighing on average four tons and measuring 12 meters in length, one of these dangerous dinos was apparently no match for the smaller stegosaurus. The evidence is a fatal stab wound in the pubis bone of the allosaur, which was conical in shape, like that of a stegosaur tail spike.

To inflict such a fatal wound in a carnivore that normally feeds on plant-eating stegosaurs, it would have required great dexterity. The lack of any signs of healing strongly suggests the allosaur died from the infection.

"They have no locking joints, even in the tail," Houston Museum of Natural Science paleontologist Robert Bakker said in a statement. "Most dinosaur tails get stiffer towards the end." But stegosaurs had massive 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."

Bakker and his colleagues compare a stegosaur's spike to today's modern horned animals, like longhorn cattle, rhinos and buffalo. These herbivores defend themselves with horns, so it's reasonable to assume spiky herbivorous dinos did the same - except with their tails instead of their heads.

The lethal blow, which took out a baseball-sized chunk of the allosaur, most likely led to a deadly infection that spread into the behemoth's thigh muscles and adjacent intestines and reproductive organs, as indicated by the lack of healing.

Stegosaurs may have had one of the smallest brains for its body size of any large animal, ever, but what they lack in brains they apparently made up for in brawn.

The findings were presented Oct. 21 at the meeting of the Geological Society of America in Vancouver, B.C.