This is Deinonychus—the only real fossil specimen of its kind on display anywhere in the world. It lived more than 100 million years ago. In the Museum, Deinonychus shares a case with three skeletal models of the first bird, whose name, Archaeopteryx, means "ancient wing." This is because parallels between the two have led to the conclusion that dinosaurs and birds are members of the same group and that, in fact, birds descended from a small dinosaur. The similarities between dromeosaurs like Deinonychus and Velociraptor, and Archaeopteryx, the earliest-known undisputed bird, are astounding. Most of the differences are differences in scale. For example, if we could take the front limb of an Archaeopteryx and blow it up to the same size as that of Deinonychus, we would be hard pressed to tell them apart. Other similarities include the S-shaped neck, the backbone held parallel to the ground, and the three primary toes on the hind feet.

Deinonychus' sickle-shaped claws and sharp teeth are the tools of a formidable predator. In this view, Deinonychus is leaping for its prey. The action of reaching for prey with clawed forelimbs like these may have been the precursor of the flight motion of birds' wings. Even the beginnings of a wing, making the animal more stable when it leapt, could have increased the effectiveness of such a predator.