National Geographic Live: Rise of the T. Rex with Dr. Lindsay Zanno

Paleontologist and National Geographic Explorer Dr. Lindsay Zanno hunts for clues in the evolutionary mystery of T. rex, which reigned as the apex predator of North America around 66 million years ago. Each year she spends several months on expedition, scouring the badlands of western North America. Along the way, she has discovered many new species—including some of the earliest predecessors of T. rex.