​The Contentious Science of Dinosaur Brawls

Why it’s so tricky to prove that dinosaurs opened cans of whoopass on each other.

by Becky Ferreira
Oct 23 2014, 9:00am

Dinosaur face-off. Image: Shutterstock

In 2008, the History Channel premiered Jurassic Fight Club, a 12-episode series about hypothetical dinosaur skirmishes. Despite my begging them to bring it back, the first season remains a one-off. That's probably for the best, because the show predictably devolved into a jumble of hype and misinformation, best embodied by its insistence on referring to fossil beds as "crime scenes."

But regardless of its lack of representation on television, interest in dinosaur fights remains perennial. And as it turns out, the actual science of dino-combat—a sub-branch of paleopathology—is just as fascinating and combative as the subject matter it investigates.

Take yesterday's announcement about a wound on an Allosaurus, supposedly inflicted by a Stegosaurus. The specimen was presented by paleontologist Robert Bakker at the meeting of the Geological Society of America, who said in a statement that "a massive infection [resulting from the attack] ate away a baseball-sized sector" of the pubis bone. His team suggested that the conical shape of the wound corresponds to the sharp cylinders of the Stegosaurus's characteristic tail spikes.

"The joints of a stegosaur tail look like a monkey's tail," said Bakker, who compared the confrontation to the "Rites of Spring" segment of Fantasia. "They were built for three-dimensional combat."

Disney does dino-fights. Image: YouTube

"There's no question that this is a combat wound," agreed paleopathologist Bruce Rothschild when I spoke to him about the specimen, which he examined with Bakker years ago. "Keep in mind where the pubis is—there's nothing else that can do that. You can tell when something's an injury and many times, you can tell what caused it. You just have to be a sleuth about it and look at all the options."

The idea of a stegosaur flailing around with a prehensile, mace-like tail is tantalizing, but that doesn't make it a slam dunk across the whole paleontological community. "Paleopathology is very interesting, and we often hear scientists spin some very colorful tales based on bite marks and other injuries found on bones," paleontologist Steve Brusatte told me.

"But whether stegosaur tails were 'built for 3D combat' and functioned 'like monkey's tails' is incredibly speculative and needs biomechanical modeling studies to test further," he noted. "I think we need to be careful not to overinterpret fossilized pathologies. I don't think the evidence is usually straightforward."

Indeed, even with abundant cross-species evidence, conclusively proving that dinosaurs got into tussles can be difficult. For example, earlier this year, paleontologist Andrew Farke published a paper analyzing evidence for combat behaviors across the Ornithischian group of dinosaurs.

Farke used three methods in tandem—observations of analogous behavior in extant animals, biomechanical simulations, and paleopathological analysis. The combination suggested that it was very likely that the study's specimens got into brawls, but Farke's team was quick to note that traumatic combat injuries are next to impossible to verify.

"For instance, a broken and healed Triceratops horn could be cited as an example of

combat," the authors wrote. "Perhaps the animal broke off its horn in a fight with another Triceratops, as happens with extant antelope, or perhaps it was damaged in a battle with Tyrannosaurus."

Did somebody say battle with a Tyrannosaurus? Image: Shutterstock

Or, the authors continued, "perhaps the horn was broken during a bad encounter with underbrush. Perhaps a developmental accident in ovum prevented full development of the horn, or a random infection created an abscess that weakened the horn to the point that it fell off."

Rothschild, on the other hand, thinks that more trust can be put into analogous pathologies across species. "Some people are diagnostic nihilists, who don't think you can compare animals across phylogenetic lines," he told me. "But I've looked at injuries and disease from the Permian and it doesn't make any difference whether it's a human, an ape, a koala bear, a giraffe, or a komodo dragon. The pathologies look very similar."

A famous example of this kind of paleopathological debate concerns the battered body of Sue the T-Rex, a particularly beleaguered tyrannosaur. Small punctures in the carnivore's face originally thought to be bike marks are now considered to be lesions caused by parasitic infection (a theory Rothschild does not buy).

Sue's punctured jaws. Image: Scott Robert Anselmo

Ambiguities like this are among the main reasons that paleontology will continue to evolve into an interdisciplinary exchange of perspectives. "A few medical doctors have ventured into the field recently and I usually trust their judgement," said Brusatte as an example."They should know a lot more about bone injuries than paleontologists."

Rothschild agrees on that point. "The reason why collaboration is so important is that we each have to convince the other of our perspective," he said.

Of course, it would be fun if experts could prove beyond doubt that all dinosaurs behaved in some absurdly fantastical manner, as they do in Jurassic Fight Club. But fossils are cantankerous about their secrets, and there is something gratifyingly mysterious about that, at least. Until scientists can send a camera back in time to the Mesozoic to capture dinosaur fights in action, we'll just have to leave the details to the imagination.