How did T. rex become the iconic apex predator of North America 66 million years ago? Paleontologist Dr. Lindsay Zanno is uncovering the answer. Each year she spends several months on expedition, scouring the badlands of western North America in search of clues. Along the way, she has discovered many new species—including some of the earliest predecessors of T. rex. Join Lindsay for a fascinating look at how a global climate crisis during the Cretaceous changed the course of evolution for this prehistoric tyrant and its ancestors.