Dinosaurs have changed quite a bit since I was a kid. Tails have been lifted, spines adjusted, skulls switched around, wrists repositioned, and feathery body coverings added, just to start. But some dinosaurs have changed more than others.

The tottering, lizard-skinned Tyrannosaurus rex of my youth shuffled awkwardly after whatever was slow enough to catch, while the modern visions of the carnivore depict a fluffy tyrant with a spine held parallel to the ground and a respectable 10-15 mile per hour run. T. rex almost three decades after I first met the predator is a very different animal. But the great armor-plated dinosaur Stegosaurus hasn’t undergone the same degree of sweeping alterations. Not quite.

When I visited Yale’s Peabody Museum of Natural