Science: Cretaceous Fairy Tales

In one episode of the classic Walt Disney film Fantasia, the dinosaurs take over the earth to the impassioned strains of Stravinsky's Rite of Spring. An adorable clutch of baby tricerotopses hatches from eggs; sloe-eyed brontosauruses wade in marshes; a bony-backed stegosaurus struggles for its life against the meat-eating Tyrannosaurus rex. But as the years flash by, the world mysteriously grows hotter and more violent: swamps evaporate, earthquakes trigger giant tidal waves, and the princely reptiles crawl across an encroaching desert to meet their certain doom.

Disney's celluloid fantasy is scarcely more elaborate than some of the theories that researchers have...