When Dinosaurs Roamed America

When Dinosaurs Roamed America (shortened to When Dinosaurs Roamed outside of the U.S.) is a two-hour American television program Film (produced in the style of a traditional nature documentary) that first aired on the Discovery Channel in 2001. It was directed by Pierre de Lespinois and narrated by actor John Goodman. The featured dinosaurs were designed by Paleo-artist and art director Mark Dubeau, noted for creating dinosaurs for many other Discovery Channel and National Geographic specials. The dinosaur animation was accomplished by animator Don Waller at Meteor Studios, in Montreal, Canada. The music was composed by Christopher Franke (ex-member from Tangerine Dream).

When Dinosaurs Roamed America premiered to 5 million viewers.[1]


Late Triassic segment (220 million years ago)[]

The program starts in the Late Triassic, near modern-day New York City. The narrator explains how the Permian mass extinction led to new forms of life, including, eventually, the most extraordinary creatures ever to walk the planet, the dinosaurs. The camera tracks a Coelophysis through the woods. The program depicts Coelophysis as preying mainly on small animals, such as insects and Icarosaurus. It encounters other, larger non-dinosaurian archosaurs such as Rutiodon and Desmatosuchus. The quick Coelophysis is portrayed as a very successful inhabitant of this world.

Early Jurassic segment (200 million years ago)[]

The program moves on to the Early Jurassic of Pennsylvania, showing a pack of Syntarsus.[note 1] These dinosaurs, closely related to Coelophysis, are hunting the primitive herbivorous dinosaur Anchisaurus, only to be driven away by a Dilophosaurus, which kills the Anchisaurus to feed its young. The narrator then explains Syntarsus and Dilophosaurus will become the gigantic carnivores such as Allosaurus and Tyrannosaurus, while Anchisaurus will become the sauropods.

Late Jurassic segment (150 million years ago)[]

The show skips to prehistoric Utah during the Late Jurassic period. The region has been engulfed by a severe drought as the seasonal rain has failed to arrive. A predatory Ceratosaurus stalks a family of Dryosaurus, including a mother and two youngsters. The predator eventually breaks its cover and charges after the small dinosaurs as they scatter. The Dryosaurus can only flee but the Ceratosaurus is quicker than they are and catches up, grabbing and killing one of the juveniles. The Ceratosaurus feasts while the others escape into a grove of pine trees and run into a herd of sauropods called Camarasaurus. They will be safe around the gentle giants. A male Stegosaurus fights off the attacking Ceratosaurus, the same individual from the earlier sequence, later on using its spiked tail and follows a female Stegosaurus constantly displaying by flushing blood into its plates. Eventually, the female decides that he is a healthy individual and the two mate. Another Ceratosaurus is seriously injured while attacking the copulating Stegosaurus and critically injured. With the onset of the rainy season, a herd of Apatosaurus arrives, followed by an Allosaurus who launches an assault against the herd while the sauropods graze but is unsuccessful due to their size and strength. The Allosaurus subsequently kills the Ceratosaurus that attacked the Dryosaurus and finally is able to feed. Later whilst following its herdmates, one Apatosaurus stumbles over a fallen tree and tumbles off of a 20 foot high cliff and cripples itself. The sauropod is mortally wounded, and its agonized bellowing is picked up by the hungry Allosaurus. When the Allosaurus arrive, they begin to eat the sauropod alive.

Mid Cretaceous segment (90 million years ago)[]

The program then shows a forest located in New Mexico during the Middle Cretaceous period. Small predatory Coelurosaurs scamper through the foliage and steal pieces of meat from a dead Zuniceratops. This smaller cousin of Triceratops had been killed by raptors and the hungry dinosaurs are feasting. The raptors chase off a lone dromaeosaur as it tries to steal some meat. The lone dromaeosaur then tries to attack a grazing Nothronychus, only to be slashed by its long claws and knocked over. Uninjured, the raptor retreats. An old male Zuniceratops is battling for dominance with a younger but healthier male whilst the herd members look on. The younger dinosaur gores the older herd leader with its right horn, wounding it. The sounds of battle are picked up by raptors and the hungry creatures follow the sounds to a clearing and watch from the foliage as the battle plays out before attacking.

The injured horned dinosaur is attacked by the pack of dromaeosaurs and is fatally wounded. Another Zuniceratops headbutts the raptor and tosses it off the struggling male. The dromaeosaurs retreat but the old Zuniceratops will not last long. Weeks later, a thunderstorm blows in and lightning illuminates the darkened skies. Panicked dinosaurs scatter but the old Zuniceratops cannot get up. As it sounds its distress call, the dromaeosaurs return and surround the wounded dinosaur. The raptors attack and soon kill it. Meanwhile, lightning ignites the dry vegetation. Fire springs up, and most of the dinosaurs scatter in all directions. Zuniceratops panic for safety and the Nothronychus follows. However, the feasting dromaeosaurs are too distracted by eating and fire surrounds the region. The raptors burn to death along with their prey. But some raptors do flee and make it to safety along with some of the other creatures.

Late Cretaceous segment (65 million years ago)[]

The program explains that dinosaurs similar to Zuniceratops evolved into the famous Triceratops. In the Late Cretaceous, Anatotitan and Triceratops browse on a rolling grassland bordered by tropical jungle, while smaller Ornithomimus peck at roots and other plants in the area. Flying pterosaurs such as Quetzalcoatlus soar overhead, looking for carcasses. A young Tyrannosaurus arrives on the scene, and the Triceratops form a defensive circle around the juveniles and display their powerful horns whilst the tyrannosaurus attempts to get through and roars repeatedly but the horned beasts stay to fight instead of fleeing. Unable to get past the horns of the defensive Triceratops, the Tyrannosaurus attacks a Quetzalcoatlus, but the pterosaur launches off and flies away from the hungry theropod. The Tyrannosaurus goes back into the trees and the Triceratops become less agitated.

At night, the young Tyrannosaurus returns to its parents, and the mother Tyrannosaurus bites it for failing to catch its own prey. The next day, the young Tyrannosaurus and its four siblings are taught by their mother to hunt. They target a herd of Anatotitan grazing in a forest clearing and after bursting from the trees, the herd scatters and flees, the four Tyrannosaurus chase after one individual and it runs straight into the forest where the mother emerges from the bushes, and, grabbing it, kills the hadrosaur by breaking its neck. The Tyrannosaurus feast.

Before they can eat, a huge asteroid, 6 miles across, hurtles towards the planet at 45000 miles an hour and as it enters the atmosphere friction turns it into a blazing missile. The asteroid crosses the ocean in just 4 minutes, crashing into the Gulf of Mexico. The impact gouges out a crater 120 miles wide and sends an incandescent plume of dust, glass and ash into the atmosphere which falls back to earth as fiery debris. The blast wave radiates outward from the impact in a circle and in minutes, everything for hundreds of miles is incinerated by the intense heat or blown apart by the blast wave. Dinosaurs in the region are vaporized in a matter of minutes.

In North America, plants and animals suffer a different fate. Some are incinerated by the mounting heat whilst others succumb to shock waves generated by the collision. Fleeing Triceratops and Anatotitan are caught by the speeding ejecta cloud and destroyed. The feasting Tyrannosaurs watch in horror as a burning blast wave hurtles towards them and flee as pieces of fiery rock rain down. Eventually, all the region's dinosaurs die including the Tyrannosaurus family. A few hours after impact, a heavy cloud of dust and ash settles over America, and temperatures drop as sunlight and heat can no longer reach the surface of the planet. Gasses such as nitrogen and carbon dioxide are burned by the heat and are washed out of the atmosphere as acid rain.

Two months after impact, the sun finally reaches the surface as the heavy cloud of ash clears away. The disaster is over, but 90% of all leaf bearing trees, ferns, vines and plants have been obliterated, and 70% of the animals have died out. Most dinosaurs are extinct.

Despite the depressing and traumatic event, life is described as being resilient, and a turtle is shown emerging from the water while out of the ashes and charred debris, several small possum-like mammals (called Purgatorius) also emerge. Meanwhile, a bird (most likely a vulture) flies overhead, explained by the narrator as the only dinosaur left. The narrator then explains that small mammals such as Purgatorius will eventually evolve into humans, and think back in awe to a time "when dinosaurs roamed America".

Related programs[]



  • John Goodman the narrator of When Dinosaurs Roamed America voiced Rex the T.Rex from the 1993 animated Dinosaur Film "We're Back! A Dinosaur Story."
  • During the scene in New York City, there appears to be a Broadway theater building. Some say that might be the Broadway Musical of Disney’s The Lion King. Right where an officer with a white hat is directing the traffic.
  • The animators that worked on When Dinosaurs Roamed America, also worked on Jurassic Park and Disney’s DINOSAUR.
  • At first glance, the Apatosaurus looked a little like the Diplodocus from the second program of Walking with Dinosaurs.
  • During the death of the Anatotitan from the T. Rex hunt, the sound effect used for the Velociraptor from Jurassic Park at the kitchen scene the same sound can be heard from. Including the sequel when one of the survivors reached the abandoned facility & were being attacked by the Raptors.
  • Some of the dinosaurs were scene in a sesame street episode (More specifically, the Elmo's World Dinosaurs episode).
  • There wasn't a single Dinosaur Egg throughout When Dinosaurs Roamed America.


  1. Megapnosaurus is referred to in this program as Syntarsus.
  2. These animals are based on a then as yet undescribed basal coelurosaur from the Moreno Hill Formation which would go on to being named Suskityrannus.[1]


  1. (3 August 2001) "THE RATINGS". Entertainment Weekly (607). Retrieved on 26 December 2011.