How did T. rex become the iconic apex predator of North America 67 million years ago? Paleontologist Dr. Lindsay Zanno is uncovering the answer. One of the world’s leading experts on the evolution of Cretaceous dinosaurs, she spends several months each year on expedition, scouring the remote badlands of western North America in search of clues. Along the way, she has discovered many new species—including one of the continent’s tiniest tyrannosaurs, Moros, which weighed only 170 pounds and stood barely five feet tall, and Siats, one of the largest American megapredators, tipping the scales at over 9,000 pounds. Dr. Zanno’s work has helped unravel how a cataclysmic climate crisis—marred by stagnant oceans, volcanic eruptions, and flooding continents – reshaped the dinosaurian world, wiping out top predators on land and in the sea. Join her as she unravels how Cretaceous climate change made room for the evolution of Tyrannosaurus rex – the most famous carnivore of all time.