Terrible Lizards: Why Dinosaurs Got That Name and How the Image Evolved

What "Terrible Lizards" Really Means

The phrase sounds like a monster-movie title, but it is actually a translation. In 1842, British anatomist Richard Owen needed a label for a small group of fossil reptiles that clearly did not belong to any living order. He fused two Greek words — deinos, meaning "fearful" or "fearfully great," and sauros, meaning "lizard" — and produced Dinosauria, the terrible lizards.

Owen was describing size and strangeness, not menace. He had no real idea what these animals looked like, and neither did anyone else. But the name carried a mood, and that mood shaped a century of art.

That gap between label and animal is the real story. For two hundred years, the terrible lizards have worked like a mirror, reflecting whatever each generation believed prehistoric life ought to be.

The First Three Terrible Lizards

Long before Owen had a name for them, three dinosaurs had already been pulled from English rock. All three were known from scraps, and all three were reconstructed with a confidence the fossils did not deserve.

Those three names became the founding members of Dinosauria. They are the original terrible lizards, and they remain the perfect cast for telling the story of how our picture of dinosaurs changed.

The most famous early attempt to put flesh on them still stands in south London. In 1854, sculptor Benjamin Waterhouse Hawkins unveiled life-size concrete dinosaurs at Crystal Palace Park, built with Owen's blessing. The Iguanodon was a squat, four-legged beast with its famous thumb spike stuck on its snout. The sculptures are wrong in almost every detail, and they are also among the most important objects in the history of paleontology.

Four Eras of Dinosaur Reconstruction

The image of the terrible lizards has been rebuilt roughly four times. Each rebuild was driven by new fossils, new techniques, and new cultural expectations.

The Victorian version treated dinosaurs as oversized lizards. The mid-century version made them monsters: tails on the ground, bodies hauled upright, blood assumed cold. The Dinosaur Renaissance flipped the script, arguing that many dinosaurs were fast, social, and far closer to birds than to any living reptile.

Modern reconstructions go further still. Soft-tissue evidence suggests many theropods had lips covering their teeth, and feathered fossils have turned the classic scaly Velociraptor into something closer to a large, bad-tempered hawk.

Terrible Lizards on Screen: The Animated Short

Independent animator David James Armsby, who works under the name Dead Sound, built an entire animated series around this history. His short film Terrible Lizards is the sixth entry in the Dinosauria series and the first of its second volume, arriving in 2024 — exactly 200 years after Megalosaurus was first described.

The plot is simple and effective. An Iguanodon wanders into a cave, helps itself to plants, and discovers too late that he has walked into a Megalosaurus nest. The mother attacks. What follows is a brutal fight, and then a twist: the Iguanodon realizes the predator was only protecting her eggs. He backs away, and both animals survive.

What makes the short unusual is that the same confrontation is staged four times, once for each era of dinosaur art.

Armsby has said the project grew out of an earlier, cancelled idea called "Through the Ages," which would have traced the changing image of Spinosaurus. He also frames the film as a celebration rather than a correction — no era is treated as stupid, because every era was doing its best with the evidence it had.

Production details are worth noting. The short required more than fifteen distinct character models, each modeled, rigged, textured, and animated for a single appearance. Backgrounds were painted in 2D and reused where possible. The score, by Ivan Dutch, deliberately echoes everything from Fantasia's "Rite of Spring" to the orchestral nature documentaries of today.

Sharp-eyed viewers have spotted a date stamp reading "Oct. 4, 1999" during the Dinosaur Renaissance segment. Community reports connect it to the premiere of the BBC's Walking with Dinosaurs, the documentary Armsby credits with sparking his own interest in the subject.

Myth vs. Reality: What "Terrible" Gets Wrong

The name survives because it is catchy, not because it is accurate. Here is how the popular image compares with the evidence.

The extinction that ended the non-avian terrible lizards was not a failure of design. It was a roughly 66-million-year-old asteroid impact compounded by volcanic activity — an event most lineages would not have survived.

How to Read a Dinosaur Reconstruction

If you want to judge paleoart instead of simply enjoying it, a few habits help.

• Check the date first. A 1975 illustration and a 2025 illustration are answering different questions with different evidence.
• Look at the hands. Modern reconstructions show palms facing inward. Older ones often show pronated, downward-facing wrists, which the anatomy does not allow.
• Look at the mouth. Lips covering the teeth are now the default for many theropods.
• Look for feathers. If a small theropod is drawn as a smooth scaly lizard, the artist is working from an older playbook.
• Check the source. The Natural History Museum's Dino Directory is a solid, regularly updated starting point for genus-level facts.

None of this means older art is worthless. The Crystal Palace statues are wrong and magnificent at the same time, and they are the reason the word "dinosaur" entered the public imagination at all.

FAQ

Why are dinosaurs called terrible lizards? The name comes from the Greek deinos ("fearful" or "fearfully great") and sauros ("lizard"). Richard Owen coined Dinosauria in 1842 to describe three unusual fossil reptiles, and the phrase terrible lizards has been attached to the group ever since.

Which dinosaurs were the first terrible lizards? Megalosaurus, Iguanodon, and Hylaeosaurus — all described from English fossils between 1824 and 1833, before the group even had a name.

Is "terrible lizards" still an accurate description? Not really. Dinosaurs were a diverse group of archosaurs, and birds are their living descendants. Calling them lizards describes a mood more than a family tree.

What is the Terrible Lizards animated short about? It is a 2024 short film by David James Armsby that retells one confrontation between an Iguanodon and a Megalosaurus four times, each in the visual style of a different era of dinosaur science.