A decaying dinosaur’s increasingly contorted neck
What’s wrong with your neck, dinosaur fossil? That looks kind of uncomfortable…
Paleontologists have long wondered by so many fossilized dinosaurs have their necks contorted into painful-looking positions—the phenomenon even has a name: opisthotonus. Various hypotheses have suggested the dinosaurs died in pain, or that their unusual posture is from rigor mortis.
Could be, though, it’s just what floppy necks do in water, according to a recent study involving chicken carcasses. Scientists recruited study subjects from among the dinosaurs’ extant relatives at a local butcher’s, plunged them underwater, and witnessed some startling acrobatics. The New York Times reports:
The teams independently concluded that the ligaments in chicken necks were like rubber bands — bendable, but contracted by default to hold the bird’s head upright against gravity. In the dead chicken, those ligaments still want to return to their natural, unstretched position, but the dead weight of the bird fights against it. In water, however, buoyancy and lack of friction allow the ligaments to contract into their natural shape, cranking the neck backward as they go.
The initial dip into water bent the necks back a full 90 degrees. Over three months, further decay made the necks bend back even further to 140 degrees. The phenomenon might not explain the cases of opisthotonus in fossils found far from water, but it does suggest an explanation for at least some of the contorted necks. Ouch, that’s enough rubbernecking for us now.
[via New York Times]