National Geographic : 1999 Nov
Mounting fossil evidence that feathers were common among theropods led Stephen Czerkas of the Dinosaur Museum in Blanding, Utah, to add plumage to an earlier model of a dromaeosaur called Deinonychus (right). Depictions of many theropod species may change as museums rethink the appearance of these precursors of modern birds. control of their body temperature than adults," says Currie. "T rex hatchlings needed a way to stay warm. What would be more logical than insulating feathers?" A photograph of a bird in flight freezes its wings in a pose-a mere suggestion of the com plicated process of flight. In a similar way the new Liaoning fossils create a snapshot of reptil ian skin evolving into feathers. Perhaps some day a new discovery will capture the moment when a flying dinosaur became a bird.  For a 3-D view of a feathered dinosaur, go to www .nationalgeographic.com/dinorama.