Last Day of the Dinosaurs

The dinosaur models created for Clash of the Dinosaurs were reused for this program. The Parasaurolophus model was used for Charonosaurus even though the legs of Charonosaurus were shorter than those of Parasaurolophus. The Deinonychus model was used for Saurornithoides (rather inaccurately, as Saurornithoides was slenderer than Deinonychus), and the Sauroposeidon model was used for Alamosaurus (even though Alamosaurus had different proportions than Sauroposeidon). The same Tyrannosaurus, Triceratops, Ankylosaurus, and Quetzalcoatlus models were also used. These models were placed upon different backdrops most of the time than those used in Clash of the Dinosaurs.

In the Pacific Northwest of North America, a Quetzalcoatlus is soaring above the valley during a rainstorm when it spots an unguarded Tyrannosaurus rex nest. The pterosaur flies down and consumes several of the hatchlings. Meanwhile, the father Tyrannosaurus is hunting for prey in the forest when his acute sense of smell alerts him to the intruder at the nest and runs back towards the nest. The Quetzalcoatlus is forced to flee when the enraged father Tyrannosaurus arrives, trying to fly off but its huge wings prevent it from flying in the thick forest. The T. rex repeatedly lunges and tries to kill it. It finally takes off just as the father T. rex bites the pterosaur's foot, though the pterosaur manages to break free of his jaws by pecking at his eye. Only one T. rex hatchling survives the carnage.

After a T. rex attacks an Ankylosaurus before being driven off, a male Triceratops loses a fight for mating rights against another male Triceratops. Two T.rex hear the commotion and close in to hunt the loser. Working together, they bring down the Triceratops. In Mongolia a herd of Charonosaurus is drinking at a watering hole in an oasis. A Saurornithoides steals an egg from a nest and flees, but the enraged mother follows the raptor into a cave. It tries to eat the egg, but the mother arrives, bellowing before the raptor's partner appears, and the Charonosaurus flees, with the Saurornithoides pair racing after it. They manage to bring down the Charonosaurus by tearing into its neck.

Meanwhile, in what is today central Mexico, a herd of Alamosaurus is roaming the plains in search of food while a female lays her eggs without nesting, as a six-mile wide asteroid formed from the collision of two asteroids 100 million years earlier enters the Earth's atmosphere. The asteroid hits the Earth in the Gulf of Mexico, creating a massive explosion and sending debris into the air. The explosion heats the air temperature near the crash site to 600° F. Hundreds of Alamosaurus are burned alive. Two minutes after impact, seismic shock waves trigger an 11.1 earthquake, which, combined with a second heat wave from the impact, wipes out the remaining Alamosaurus. Most of their eggs are destroyed but some survive, buried under the cool soil.

The effects of the collision begin to affect the animals in British Columbia, with the 11.1 magnitude earthquake rippling through the valley. Falling debris litters the ground and drive animals from the valley. Several Triceratops and Ankylosaurus are engulfed by a 300° ejecta cloud and burnt to death. Fifteen minutes after impact, the ejecta cloud has spread to the Pacific Northwest and threatens to in-circulate the entire planet in ash. A pair of Quetzalcoatlus tries to fly away, but pieces of flaming debris shower the valley. Suffering from burnt wings, the male pterosaur falls from the sky to his death. After trying to save her mate, the also wounded female is forced to land in the valley. The effects of the ejecta also caused lightning storms to strike the valley.

The soaring temperatures create high humidity in the valley and force the Triceratops to keep moving. Many of the dead dinosaurs provide plentiful food for the hungry Tyrannosaurus. The debris create massive fires that devastate forests of the Pacific Northwest. In the valley, the air pressure plummets, creating a vacuum that sucks in the raging flames and ignites a firestorm, causing temperatures in the valley to reaches 1800 °F. The female Quetzalcoatlus stands over her mate's body but panics when the vegetation around her ignites. She manages to take off despite her tattered wings, leaving the dead male behind. Smaller animals hide underground while the larger animals are forced to flee.

In Mongolia, forty-five minutes since the impact, the ejecta cloud rolls in from the east, increasing the temperature around Mongolia by several degrees every second until it reaches 300°, causing three Charonosaurus and a pair of Saurornithoides to use a cave for shelter (unenthusiastically with each other as well). The temperatures return to normal after five hours, and the Saurornithoides run outside to feast on a Charonosaurus corpse, while two of the surviving Charonosaurus travel to the watering hole. The third stays behind. Soon the ejecta cloud causes a sandstorm, suffocating the two Charonosaurus alive. The pair of Saurornithoides survive by hiding behind their prey, while the third Charonosaurus remains in the cave. A day passes, and the Saurornithoides return to the watering hole, where the last Charonosaurus is drinking. The Saurornithoides are desperately hungry, yet are weak from their ordeal. One of them recklessly attacks the Charonosaurus, but the hadrosaur collapses on top of it, killing it in the process. The remaining Saurornithoides resorts to eating the corpse of its companion.

Four days since impact, food is in short supply across the entire planet. In the Pacific Northwest, four Triceratops head towards an island in search of food. The earthquake caused by the impact event forms a huge megatsunami, but also causes the water to recede and form a land bridge to the island. Three of the Triceratops cross the land bridge to the island. The female Quetzalcoatlus lands, where she eats a stranded fish, just as the megatsunami builds and races towards the shore. The Quetzalcoatlus attempts to take off but is caught into the vast wave and drowns, with the wave subsequently drowning the three Triceratops as well.

Ten days have passed since impact, and few dinosaurs remain. But during that time, the after-shocks began awaking violent/super volcanic eruptions around the earth. In Mongolia, the Charonosaurus stays close to the watering hole, but collapses and dies from inhaling hydrogen sulfide that rose from the watering hole. The Saurornithoides runs up to the dead Charonosaurus, but it too is killed by the poisonous gas.

A month and a half later, in the Pacific Northwest, a handful of dinosaurs patrol the wasteland. A starving but weak Ankylosaurus finds a small bush, but it's almost forced to fight over it when a wandering Triceratops appears, until the Tyrannosaurus arrives. The Tyrannosaurus loses an eye to his prey's horn, but he manages to break off one of its horns and kills it by simply lunging and biting down hard on the neck. The Tyrannosaurus then turns his attention to the Ankylosaurus and after being struck in the right leg, flips it over and rips out its throat. He heads back to the dead Triceratops, but trips over the Ankylosaurus and is impaled through the neck on the Triceratops's remaining horn. In Mexico, an Alamosaurus baby emerges from an egg that was sheltered away in the ground. All around the world, small handfuls of dinosaurs try to start over, but their species are beyond hope for replenishing their numbers. In the end, inbreeding, disease, and starvation will wipe out their populations until a single Alamosaurus remains, only to die in the wasteland too, and it only took 160 million years to bring the dinosaurs to this catastrophic point in their evolution.

But life on Earth was not completely destroyed: fish and crocodiles surviving underwater; small mammals, snakes, insects, arachnids, and lizards hid underground; birds flew or swam away from the disaster. Three years pass before sunlight finally reaches the planet again, and plant life finally carpets the Earth again, setting the stage for a new era: the era of mammals. Mammals now multiply and diversify, with countless species of mammals evolving, until 10,000 species explode across the planet and one species, humans, eventually rule the planet like the dinosaurs once had.

• Harris, Bill (November 20, 2010). "'Dinosaurs' documentary compelling". Toronto Sun. Retrieved November 13, 2011.
• "World Premiere for 3D Special on Discovery World HD". Broadcaster Magazine. December 1, 2010. Retrieved November 13, 2011.

• Last Day of the Dinosaurs at Discovery.com