The boughs and evergreen leaves of the tropical forest filter the sunlight into fine steamy beams that throw a dappled pattern down into the gloom of the jungle floor. This is the domain of the brightly-colored birds, the pterodactyl pterosaurs, with their larger wings, being banished to the more open spaces above. Suddenly the raucous chattering of the birds is hushed, and a deep still silence falls in the shadowy forest. The birds have sensed something dangerous. The light patterns ply upon the leathery surface of something dark and indistinct in the sparse undergrowth. With a gasp of air from cavernous lungs, a huge animal rises to its hind feet, pushing itself up on massive legs, steadying itself with clawed forefeet. The great eyes, gummy after sleep and torpor, blink and look around.