According to dinosaur lore, pachycephalosaurs, bipedal Cretaceous beasts with enormously thick domed skulls, bang their heads like bighorn sheep do today. But a new analysis suggests this is far from the case; rather, pachycephalosaurs (pack-ee-SEH’-fa-low-sawrs) may have moved more like kangaroos, using their tails as a tripod that could support them as they unleashed powerful kicks at rivals.
Paleontologists found evidence of this kickboxing behavior by analyzing a well-preserved skeleton of pachycephalosaurusmaking a virtual 3D model of it and noting which parts of the dinosaurThe anatomy of resembled that of a kangaroo and moved in surprisingly similar ways.
“The skeleton in our study supports that they used their tail for support like kangaroos do, but not that they ran into each other and bumped their heads like bighorn sheep. [do]Cary Woodruff, curator of vertebrate paleontology at the Frost Science Museum in Miami, who is leading the investigation, told WordsSideKick.com.
The research was presented Nov. 2 at the annual conference of the Society of Vertebrate Paleontology in Toronto, and has yet to be published in a peer-reviewed journal.
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Pachycephalosaurs are the poster children of weird-looking dinosaurs. “They have this big bowling ball over their heads,” Woodruff said. “They have these really pointy, carnivorous dinosaur-like teeth at the front of their mouths, but they ate plants. Everything about them is weird.”
For a long time it was thought that these cretaceous period (145 million to 66 million years ago) weirdos would run at each other and bump their melon heads, possibly to compete for mates, food, or territory. And while some paleontologists have challenged this headbutting idea for the past two decades, it’s still a popular concept.
Although many paleontologists have studied the skulls of pachycephalosaurs, analysis of the rest of the body is scarce because their skeletons are rarely well preserved, Woodruff said. But, access to a well-preserved Pachycephalosaurus wyomingensis specimen from the Hell Creek Formation of the American West meant that Woodruff could examine its spine, as well as other anatomical features that might offer clues to its behavior.
After using a laser scanner to make a virtual 3D model of P. wyomingensisWoodruff focused on the dinosaur’s strange rear vertebrae, which had wavy ends, almost as if someone had placed two ribbed potato chips on both ends of each vertebra. These ruffles fit together perfectly, like a stack of potato chips, Woodruff noted. Previously, paleontologists had suggested that these bristling vertebrae helped with headbutting behavior, perhaps distributing the forces of high-velocity headbutt impacts, Woodruff said.
But when Woodruff and his colleagues examined the skeletons of other head-butting animals, including bighorn sheep, muskox and deer, none of them had bristling vertebrae; however, the kangaroos did.
The new study supports a hypothesis, first formulated in the 1970s, that pachycephalosaurs might have used their tails for support, much like kangaroos do. That is because P. wyomingensis it shares several anatomical features with kangaroos, not only in the vertebrae, but also in the pelvis and tail.
It is even possible that pachycephalosaurs had kickboxing-like behavior. When kangaroos kickbox, they do so from a tripod position, with their tail supporting part of their body weight. “To kickbox, a kangaroo first has to lean back on its tail, and once it’s propped up, it can kick,” Woodruff said.
Although it is only a hypothesis, “there is a possibility that [pachycephalosaurs] they could have engaged in their own form of kickboxing-like behavior,” he said.
But aside from kickboxing, did pachycephalosaurs put their iconic heads together? If they did, it probably wasn’t at high speeds, since their anatomy is nothing like that of charging animals, Woodruff said. Perhaps pachycephalosaurs were more like large cows, not attacking each other, but sometimes pushing each other at low speeds. “If, and that’s a big if, pachycephalosaurs used their heads to fight each other,” Woodruff said, so they were probably “sumo wrestlers, not jousters.”
While this SVP submission offered promising evidence of dinosaur kickboxing behavior, the peer-reviewed and published study will likely reveal more details, said Joseph Peterson, a paleontologist and pachycephalosaur expert at the University of Wisconsin Oshkosh who was not involved in the research. . “This has the potential to really change the way we look at these particular animals,” Peterson told LiveScience.
And while the finds are surprising, they just add to the overall weirdness of pachycephalosaurs. “These are really strange animals,” Peterson said. “This adds a new dimension to it.”