Seasons & episodes

S44 · E25Killer Floods 2017-11-08 · 55 min＋

All over the world, scientists are discovering traces of ancient floods on a scale that dwarfs even the most severe flood disasters of recent times. What triggered these cataclysmic floods, and could they strike again? In the Channeled Scablands of Washington State, the level prairie gives way to bizarre, gargantuan rock formations.

S44 · E26Extreme Animal Weapons 2017-11-22 · 55 min＋

From lobster claws and dog teeth to bee stings and snake fangs, every creature depends on a weapon. But some are armed to extremes that make no practical sense—whether it’s bull elks with giant 40-pound antler racks or tiny rhinoceros beetles with horns bigger than their body. What explains giant tusks, horns, and claws that can slow an animal down and even impair health and nutrition? NOVA investigates the riddle of outsize weaponry and uncovers a bold new theory about what triggers an animal arms race. In creatures as varied as dung beetles and saber-toothed tigers, shrimp and elephants, the same hidden factors trigger the race and, once started, these arms races unfold in exactly the same pattern. Join scientists as they crack the secret biological code that underlies nature’s battleground.

S44 · E27Bird Brain 2017-12-20 · 55 min＋

Watch astonishing tests of avian aptitude: parrots that can plan for the future, jackdaws that can “read” human faces, and crows that can solve multi-step puzzles with tools like pebbles, sticks, and hooks. Could these just be clever tricks, based on instinct or triggered by subtle cues from their human handlers?

S44 · E28Day the Dinosaurs Died 2017-12-27 · 55 min＋

66 million years ago, a seven-mile-wide asteroid collided with Earth, triggering a chain of events that coincide with the end of the dinosaurs. But experts have long debated exactly what happened when the asteroid struck and how the giant beasts met their end. Now, scientists have uncovered compelling new clues about the catastrophe.