When the dinosaurs died out some 65 million years ago, many perished in the exact same iconic pose: neck, spine, and tail curved backward, mouth open, limbs contracted. The reason for this characteristic dino death pose has been unclear. Conventional wisdom held that the dead dinos’ pose was struck when the muscles contracted under rigor mortis or because the dinos’ tendons and ligaments had dried up, suggesting that their bodies had been exposed to the sun for a long time. But if so, why hadn’t the bones been scattered by scavengers?
Now the answer is coming from the corpses of some modern-day birds and mammals, which look very similar when they have died under certain specific conditions. The connection was never made before because paleontologists rarely see dead parrots. But veterinarians do. And luckily, Cynthia Marshall Faux is both—with doctorates in veterinary medicine as well as geology (with a specialty in vertebrate paleontology).
It was clear to Faux that the dinosaurs’ pose was a sign of opisthotonos, a condition that results from an injury affecting the cerebellum, which regulates fine muscle movement. While working at the Museum of the Rockies in Bozeman, Montana, Faux collaborated with Kevin Padian, a professor of integrative biology and curator of the Museum of Paleontology at the University of California at Berkeley, to make her argument: Brain injury during death, not later rigor mortis, explains the typical look of dino fossils. “Paleontologists are familiar with dead things,” says Faux, who is a vet in Idaho. “But I know about dying things. I see animals die all the time. I see the process, not just the result.”
Adding to the intrigue is that opisthotonos is usually seen in warm-blooded animals like birds and mammals but not reptiles. Faux’s paper on opisthotonos, published in March, rethinks dinosaurs not just as having died for reasons other than meteor impacts and volcanic eruptions but also advances the argument that these creatures may have had hot blood pumping through their veins.
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