The Age of Reptiles is a fictionalized view of the past derived from popular, and generally fairly outdated, views of the succession of the dinosaur-dominated Mesozoic and the mammal-dominated Cenozoic. This concept, which is particularly popular in fantasy and pulp settings, posits that before the modern age where warm-blooded species dominate, there was a period where reptilian, cold-blooded beings ruled the world.
Depending on the setting in question, the modern age will be ruled by humans, Demihumans such as elves, dwarves and orcs, mammalian Beast Men, Bird People or any combination thereof. During the earlier Age of Reptiles, the world was instead dominated by Lizard Folk, Snake People, dragons, or similar reptilian beings. Dinosaurs of varying levels of accuracy are also a common element, both as wildlife and as sapient beings themselves. In particular, Snake People and Lizard Folk are very popular choices for fantasy Precursors, often being portrayed as civilizations that were ancient and declining when the oldest warm-blooded empires were still young. Elements of 1 Million B.C. are often mixed into this, and during this period the world was typically warm, tropical, and lush. At least some of the fauna will be portrayed as Prehistoric Monsters.
The decline of the Age of Reptiles and beginning of that of the warm-blooded species tends to be caused by a number of recurring factors. The reptiles are often portrayed as ponderous in personality, and slow to innovate and breed; this often allows the mammal races to outnumber, outcompete and displace them. Global cooling making the world more inhospitable to cold-blooded beings is also a common factor. Occasionally, a more elaborate disaster may have brought about the end of the Age of Reptiles, in which case this may overlap with Phlebotinum Killed the Dinosaurs. Regardless, the rulers of the Age of Reptiles rarely vanish entirely, and often hang on in Vestigial Empires and Lost Worlds tucked in scattered corners of the land, clinging on to scraps of their former glories and scheming against the upstart warm-bloods.
Not to be confused with the comic book series Age of Reptiles.
- Black Panther: One arc sees Wakanda being plagued by the Originators, bestial monsters who ruled the country in the ages before humans arrived there. One of these races is the Simbi, a race of snake-like beings with multiple arms.
- Super Mario Bros.: Dinohattan is a dimension where dinosaurs were the ruling species on Earth rather than mammals. The dinosaurs themselves are the Precursors in this case, as the modern humanoids are all descended from dinos like our humans were from early primates; due to budget constraints, however, they look like modern humans with minor physical differences.
- The Balanced Sword: The Saurans are a type of Lizard Folk, reputedly descended from dragons, who serve as the setting's ancient and advanced civilization.
- Conan the Barbarian: The Serpent Men of Kull and Conan's times are the last remnants of a great civilization that ruled the world during the Paleozoic, but collapsed during the Triassic when the dinosaurs arose.
- Malazan Book of the Fallen: The K'Chain Che'Malle were a reptilian race that arose, flourished, ruled the world, and collapsed long before the time of all other sapient species.
- The Nameless City by H. P. Lovecraft narrates a man finding the titular city in the middle of the Arabian desert. When he explores it, he discovers the ancient city was built by ancient reptilian aliens that once in ancient times dominated the land.
- Doctor Who: The Silurian are a race of highly advanced reptilian humanoids who predated men and ruled the ancient Earth.
- Star Trek:
- Star Trek: Voyager: In "Distant Origin", the Voyager crew meets an alien race called the Voth that evolved from dinosaurs on Earth.
- Star Trek: Enterprise: In "Azati Prime", Archer describes the end of Earth's age of reptiles and their supplement by more intelligent mammals to taunt Dolim.
Archer: I'll bet you didn't know this, but at one time most of my world was ruled by reptiles.
Dolim: I wasn't aware of that.
Archer: A comet hit around 65 million years ago — caused a mass extinction. Most of the reptiles died out. Mammals became the dominant species.
Dolim: How unfortunate.
Archer: Still, the reptiles might've come out on top if it hadn't been for a slight disadvantage.
Dolim: And what was that?
Archer: They had brains the size of a walnut. That's very small. Apparently, it is a constant in the universe.
- Dinosaurs: This is the central idea behind the series, which is about dinosaurs having a civilization almost exactly like ours. When Jim Henson first conceived of the show, he meant to parallel the extinction of the dinosaurs to our own potential fate if we don't take better care of the environment. This idea is driven home by the Series Finale, in which the dinosaurs thoughtlessly destroy their environment and cause their own extinction.
- Delta Green: The Serpent-Folk rose in prominence in the Paleozoic era, 500 million years ago. They built a great civilization under the reign of the Great Old Ones but ended up destroying themselves in a self-generated apocalypse. The very few surviving serpent-folk have tried to infiltrate human society, but luckily they're as likely to kill each other as to kill human beings.
- Dungeons & Dragons: In Forgotten Realms, ancient Faerün was ruled by a number of primordial creator races who were for the most part cold-blooded and flourished in the ancient world's tropical climes. The Sarrukh were Snake People, and created an immense variety of reptilian races as servants and soldiers, including the lizardfolk, nagas, yuan-ti, and pterafolk; the batrachi were instead froglike, and created a number of amphibious and fishlike servitor races. The only warm-blooded creator race, the avian aearee, arose last and towards the end of the primordial period, while the humans spent this time as primitive ape-men and the giants as a single kingdom in the north. After the fall of the creator races, the dragons and the yuan-ti arose as Faerûn's dominant powers and remained as such until the former lost most of their power in wars against the giants and elves and the latter gradually overtaken by human, elven, and dwarven civilization.
- Exalted: Downplayed. The prehistoric times when the Primordials ruled the world where home to a large number of species, including humans, but the setting's lore still presents a fairly clear transition in the world's dominant civilizations between the ancient, reptilian Dragon Kings and, once these began to die out and decline, the human civilization that they nurtured and taught.
- Pathfinder: In its ancient days, before its modern warm-blooded races arose, Golarion was ruled chiefly by reptilian beings. The most prominent of these were the serpentfolk, who ruled a vast empire in the upper Darklands and in Garund and whose legacy led this period to being named the Age of Serpents. Besides them, this era also saw the golden age of lizardfolk culture and expansion, while the snakelike nagas ruled an empire in ancient Vudra and the reptilian troglodytes built their own in the deepest parts of the Darklands. Dragons also came to Golarion during this period, often allying with the world's reptilian civilizations and establishing their own direct rule over ancient Tian Xia. Over time, however, mammalian species such as humans and elves established themselves and either outbred their competitors or actively displaced them, as when Azlant destroyed the serpentfolk empire, leading to the modern age of warm-blooded rule.
- Warhammer: The ancient past, both before and during the time of the Old Ones, saw reptilian species rule the ancient world. The Old Ones themselves are often described as reptilian or amphibious in appearance, as are the lizardmen they created as soldiers and servants. Besides them, the dragons and dragon ogres were both widespread and powerful species before the Old Ones came, while the one-eyed, reptilian fimir were the Chaos Gods' favored servants and ruled much of the world in their name; the zoats, a mysterious species of reptilian centaurs, also date back to this period. Over time, however, the Old Ones left, the lizardmen lost most of their ancient holdings, the dragons and dragon ogres gradually began to die out, the zoats shrunk in number and retreated to isolated hermitages and the fimir lost their gods' favor to the rapidly spreading human race, leading to the modern age where warm-blooded races rule over most of the world.
- The World of Darkness:
- Genius: The Transgression: The Lemurians, formally known as the Third Race, were a species of snake people formed from fallacious theories of prehuman precursors and reptilian conspiracies. They ruled the Earth and humanity in days long past until they accidentally erased themselves from the timeline.
- Werewolf: The Apocalypse: The Lizard Kings, the ancestors of the Mokolé werereptiles, were Earth's first sapient inhabitants and ruled during the Mesozoic. They were wiped out entirely in a supernatural event called the Wonder-Work that coincided with the extinction of the dinosaurs and the start of the Cenozoic.
- Chrono Trigger: 65 Million BC shows that the world used to be ruled by a humanoid reptile race called the Reptites, who had a technologically-advanced civilization far superior to that of contemporary humans. However, the Reptites went extinct due to Lavos falling on their lair, leaving humanity to thrive thanks to the Dreamstone that came with Lavos. The New Game+ gives Chrono the option of facing off against Lavos before the downfall of the Reptites, making them the dominant species celebrating at the Millennial Fair.
- Iji: The Tasen and Komato are descendant of Earth's former ruling species, who left long ago. When the Tasen discover the world they just bombed back into the stone age is "Origin", they freak out at what the Komato will do to them for it, but the Komato were already more than happy to exterminate them and finish the planet off.
- Ys VIII: Lacrimosa of Dana: The Isle of Seiren is a holdover of a time when dinosaur-like beasts called Primordials ruled the earth, long before humans and modern beasts came into existence, with said island being the last refuge of these creatures in present day.