Helmet-headed dinosaurs kickbox like kangaroos, new study suggests
Dinosaur lore has it that pachycephalosaurs — bipedal, Cretaceous beasts with enormously thick, domed skulls — banged their heads vigorously as 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 to prop them up as they launched powerful kicks at rivals.
Paleontologists have found evidence for this kickboxing behavior through a well-preserved skeleton of Pachycephalosauruscreate a virtual 3D model of it and notice that parts of the dinosaurIts anatomy resembled that of a kangaroo and moved in strikingly similar ways.
“The skeleton in our study supports that they used their tails for support like kangaroos do, but not that they ran towards each other and banged their heads together like bighorn sheep. [do]” Cary Woodruff (opens in new tab)the curator of vertebrate paleontology at Miami’s Frost Museum of Science, who is leading the research, told Live Science.
The research was presented Nov. 2 at the Society of Vertebrate Paleontology’s annual conference in Toronto and has yet to be published in a peer-reviewed journal.
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Pachycephalosaurs are the poster children for bizarre-looking dinosaurs. “They have a big bowling ball on their head,” Woodruff said. “They have really pointy, carnivorous, dinosaur-like teeth in their mouths, but they ate plants. Everything about them is weird.”
For a long time it was thought that this Cretaceous Age (145 million to 66 million years ago) madmen ran to each other and smashed their melon heads together, possibly competing for mates, food or territory. And while a few paleontologists have challenged this head-butting idea over the past two decades, it remains a popular concept.
While many paleontologists have studied pachycephalosaur skulls, 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 Woodruff could examine his spine, as well as other anatomical features that could provide clues about his behavior.
After using a laser scanner to create a virtual 3D model of p. WyomingensisWoodruff focused on the dinosaur’s strange dorsal vertebrae, which had ruffled ends — almost as if someone had placed two ridged chips on either end of each vertebra. These ruffles fit together perfectly, as a stack of chips would, Woodruff noted. Previously, paleontologists had suggested that these undulated vortices aided in headbutting, perhaps by distributing forces from high-velocity headbutts, Woodruff said.
But when Woodruff and colleagues examined the skeletons of other head-butting animals, including bighorn sheep, muskox and deer, none of them had ruffled vertebrae; however, kangaroos did.
The new study supports the hypothesis, first formulated in the 1970s, that pachycephalosaurs may have used their tails for support, as kangaroos do. That is because p. Wyomingensis shares several anatomical features with kangaroos – not only on its vertebrae, but also on its pelvis and tail.
It’s even possible that pachycephalosaurs engaged in kickboxing-like behavior. When kangaroos kickbox, they do so from a tripod position, with the tail supporting some of their body weight. “To kickbox, a kangaroo must first lean back on its tail, and once propped up, it can kick out,” Woodruff said.
Although it is only a hypothesis, “there is a possibility that they [pachycephalosaurs] could have exhibited their own form of kickboxing-like behavior,” he said.
But did pachycephalosaurs ram their iconic heads against each other in addition to kickboxing? If they did, it probably wasn’t at high speeds, as their anatomy doesn’t resemble those of ramming animals, Woodruff said. Perhaps pachycephalosaurs were more like large cows, not charging each other, but sometimes pushing against each other at slow speeds. “If — and that’s a big if — pachycephalosaurs used their heads to fight each other,” Woodruff said, then they were probably “sumo wrestlers, not jousters.”
While this SVP presentation offered promising evidence for dinosaur kickboxing behavior, the peer-reviewed and published study is likely to reveal more details, said Joseph Peterson, a paleontologist and pachycephalosaur expert at the University of Wisconsin Oshkosh who was not involved in the study. . “This has the potential to really change the way we look at these particular animals,” Peterson told Live Science.
And while the findings are surprising, they just add to the overall craziness of pachycephalosaurs. “These are really strange animals,” Peterson said. “This adds a new dimension to it.”
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