- Kenneth Branagh also provided narration for the follow-up series "Walking with Beasts" (2001) and "Walking with Monsters" (2005).
- The program received much criticism for presenting theories as solid facts. The creators argued that while they were making a documentary, their goal was also to entertain, and since the theories about these prehistoric creatures always change, they couldn't possibly have made a TV show that accurately depicts what the world of the dinosaurs may have been like. And they were right - many theories presented in the show have by now been declared outdated and incorrect.
- The longest shot to render was from the second episode, when a herd of Diplodocus passes by above the camera. Each frame took more than an hour to render.
- Mike Milne from Framestore originally declined the request to produce CGI animation for the series, but after having thought through the possibilities, he finally offered to help out. It turned out to be a wise decision, and the series was a smash hit.
- Early animation tests made for the series contained computer generated reconstructions of the carnivore Eustreptospondylus, the long-necked Cetiosaurus (with an incorrectly positioned neck), a flock of flying Rhamphorhynchus and a beached Liopleurodon (whose tail was a physical prop operated by Tim Haines). Of these, only the Cetiosaurus didn't get to be featured in the finished series.
- For dinosaur drool, the filming crew used huge quantities of KY jelly. Reportedly, many shop owners gave them puzzled faces when they bought it.
- The success of the series not only lead to several sequels and imitations, but also gave rise to various other, part scientific-part fictional television shows and movies. These use compelling narrative and often movie-quality special effects to entertain and educate viewers.
- Initially 24 prehistoric animals were planned to appear in the series, but the finished production bumped this number up to 40.
- Producer Tim Haines at first approached the animators at Industrial Lights and Magic to create the computer graphics for the series, but their working fee would have been a staggering $10,000 per second of animation. This is how the England-based Framestore came into picture, but they still had to work very hard and precise to keep production costs under budget.
- The ending with the Plateosaurus, the first truly giant dinosaurs, is a lead-in to the next episode, which features sauropods, the largest animals of all time. In addition to this, Plateosaurus is a prosauropod, meaning it is related to the sauropods from the next episode.
- The website and companion book state that the cynodonts in this episode are based on Thrinaxodon, though scaled up. Thrinaxodon hasn't been found in North America, but its presence here in the series is based on a set of fossil teeth later described as Kraterokheirodon.
- Featured creatures in this episode: Coelophysis, Placerias, Postosuchus, Peteinosaurus, Thrinaxodon (the cynodonts), Plateosaurus. The book also features Metoposaurus (large amphibian similar to Koolasuchus from the fifth episode), phytosaurs (crocodile-like aquatic reptiles) and Icarosaurus (small gliding reptiles similar to the lizard Draco volans).
- Although the series is called "Walking With Dinosaurs", only two kinds of dinosaur appear in this episode, and one (Plateosaurus) only appears at the end, excluding stock-footage used in the introduction.
- Recent scientific studies reveal that many statements ("facts" and theories alike) described in this episode had been false all along. These new discoveries include: - The Postosuchus was indeed capable of walking on its hind legs. The program states it could only rear up for a short amount of time. - For decades, the small dinosaur Coelophysis has been famous of its cannibalistic traits. Newer studies indicate it didn't eat its own kind, and the bone fragments found inside their fossils came from other kind of reptiles, or were simply the remains of smaller Coelophysis that had been crushed by larger ones. - Plateosaurus could not in fact walk on all fours as the episode tells us. Furthermore, it held its "hands" with the palms facing inward.
- The depiction of Diplodocus with iguana-like spikes on its back was based on recent fossil findings showing impressions of such spikes preserved along with the bones. Post-2000 encyclopedias depict Diplodocus like this, as well. Though perhaps even this detail would become erroneous, as suggested by some recent studies made by palaeontologists. It could be that the spines didn't form a neat line over the animal's spine, but were arranged in a random pattern over its back.
- In 2005, it was discovered that Ornitholestes actually didn't have a nasal crest as depicted in this episode (based on contemporary science). The "crest" was actually a broken nasal bone.
- The egg-laying method of Diplodocus- depositing eggs through a long fleshy ovipositor- as portrayed in this episode is not supported by fossil evidence. However, sauropods like Diplodocus were too heavy to crouch while laying eggs, and dropping eggs from several meters high would surely damage them. Thus, it's not unlikely an ovipositor-like appendage existed. The filmmakers based the concept on turtles, which also use a short ovipositor to deposit eggs.
- Featured creatures in this episode: Diplodocus, Brachiosaurus, Stegosaurus, Allosaurus, Anurognathus, Ornitholestes, Dryosaurus (small bipeds seen throughout episode). The book also features the small Ornitholestes-like predator Coelurus.
- Studies made after this show had been produced suggest that Sauropods actually had their nostrils on the front of their head. For the last couple of decades, they have mostly been pictured as having them on their "forehead" or on the top of their head, between the eyes. Thus, in a strange turn of fate, the older, outdated restorations are actually more correct than most of the newer ones in this respect. Another aspect of these animals that has been reevaluated is their neck-posture. According to the program, Diplodocus and related dinosaurs had stiff necks that they kept close to the ground. Scientists now say they held them at an angle of 45°.
- Scientists believe that Sauropods like Diplodocus needed much more time to reach adulthood (many decades) as opposed to the ten years the program claims.
- The shots of the young Ophthalmosaurus chasing fish were taken from an older BBC documentary in which penguins chased fish. The penguins were simply erased from the shot and replaced with CG Ophthalmosaurus, ensuring realistic interaction with the fish.
- Although the show is called "Walking With Dinosaurs", only one type of dinosaur appears in this episode, not counting the preview for the next episode at the end.
- The Eustreptospondylus animation is actually a modified Allosaurus animation with different colors and without the characteristic eyebrow ridges.
- Featured creatures: Ophthalmosaurus, Cryptoclidus, Liopleurodon, Eustreptospondylus, Rhamphorhynchus, Hybodus (sharks), Perisphinctes (ammonites), Leptolepis (fish) and horseshoe crab.
- Although Liopleurodon in this episode is depicted as being much larger than in real life (25 m as opposed to 10 m), a 15 m long juvenile pliosaur found in 2002, the "Monster of Aramberri", is possibly a Liopleurodon.
- Many people would argue that the rise in Liopleurodon's popularity can be attributed to this episode's portrayal of the animal. For example, nearly all of the toys that came out after it had aired carried the same color scheme it had in the show.
- Aside from its somewhat dubious increase in size, the Liopleurodon's weight also seems to have been drastically overestimated. The narrator claims it weighs 150 tons, more recent studies indicate it wouldn't have been bulky enough to weigh as much. 30 tons seems to be a more likely estimate, though if the animal really did grow to 25 meters, as the episode suggests, it may have weighed more, but certainly less than 150 tons.
- Featured creatures: Ornithocheirus, Tapejara, Iguanodon, Polacanthus, Utahraptor, Iberomesornis (the birds), Saurophtirus (the louse-like insect seen parasitizing the Ornithocheirus). According to the BBC website, the Liopleurodon-like pliosaur seen in one shot (recycled from the previous episode) is a Plesiopleuron.
- There is no direct proof of Saurophtirus sucking the blood of pterosaurs, but due to its resemblance to bat lice and the likelihood that pterosaurs were covered in fur it is considered likely.
- Since this episode aired, the American dinosaur the narrator describes as Iguanodon has been renamed Dakotadon (the European Iguanodon's name hasn't changed). It has also been proved that these animals mostly walked on their hind legs, thanks to their balancing tails. In this program, while the narration does tell us that they were capable of walking on two legs, the animals are mostly shown on all fours, and only rear up for feeding and running.
