Follow TV Tropes


Speculative Biology

Go To
Just one example of the huge diversity of future creatures imagined by both biologists and artists.

"Speculative biology" (also referred to as "speculative zoology", though it is by no means limited to animals) is a sub-genre of science fiction which combines Speculative Fiction with creature design, and deals with evolution in the future, on other worlds, or in alternate timelines, the same way that many other sci-fi works discuss technology.

The broader genre of speculative biology contains a number of distinct subgenres within itself:

  • Alternative Evolution: A subgenre of both Speculative Biology and Alternate History, these works focus on exploring how life would have developed if some crucial event in Earth's deep past had gone differently. A particularly common scenario focuses on what would have happened if non-avian dinosaurs didn't become extinct. Some works attempt to entirely restructure the Earth's present biosphere to account for these changes; others maintain its present form while changing, adding or removing features or species as needed.
  • "Bottle Worlds": These settings focus on creatures native to isolated environments, away from established biospheres and more familiar beings. The oldest permutation of this subgenre uses isolated islands, plateaus or other inaccessible locations, whether real or invented ones, home to relics of bygone linages or bizarre creatures evolved in isolation from the world.
    • "Seeded Worlds": A more recent variant, which instead imagines settings where a select number of organisms, usually small and generalized ones, are placed on an uninhabited world to evolve on their own.
  • Cryptozoology: Some speculative works try to re-design mythical creatures from fantasy and folklore to be more "realistic" and biologically plausible. Mer-people and dragons are among the two most popular candidates, exploring the development of sapient aquatic humanoids or the evolution of large flying reptiles, though other monster reconstructions such as Bigfootnote , Angels and Demons note , Unicorns note , Giantsnote , Vampiresnote , and Fairies/Pixies note  are not unheard of in this subgenre.
    • Reconstructed Fiction: A subtype of Cryptozoology which focuses on reconstructing fictitious animals or monsters from modern media such as Godzilla, King Kong, or Pokémon into more biologically plausible forms.
  • Future Evolution: Probably the most iconic of the subgenres and the one most people are familiar with. Instead of asking "what could have been?", this subgenre asks "what will happen in the future?" The most common situation discussed in these works is After the End, and almost invariably involves dealing with the eventual fate of humanity. In some cases, exploring the fate of Humanity's Wake is a major concern; one particular variant involves the hypothetical future evolution of humans into different species. In others, humans are written out early on, such as by having humanity go extinct or migrate off-world, to focus on the development of other creatures instead.
  • Xenobiology: This subgenre leaves Earth and its history behind entirely to instead construct and explore entirely alien biospheres, whether on other worlds or in other dimensions entirely. Common concerns include considering what traits are intrinsic to life, instead of simply being native to Earth's family of beings, and exploring what shapes living creatures might take under truly alien or hostile conditions, such as evolving on a tidally-locked planet or in the atmosphere of a gas giant or on the moon(s) of said gas giants.

Most of these stories tend to have no defined villains, or if there are, they're mostly just treated as an afterthought as the predators of the ecosystems portrayed in the story are enough of forces to provide conflict to these stories just like their past/earth counterparts. If an antagonistic force is prevalent in the story, it's often either in the form of Evilutionary Biologist who wants to see how humans/certain animals would end up if they hasten their "evolution", an invasive species ravaging any ecosystem they weren't in before, or from a sapient species or culture that has little to no respect of their homeworld's ecosystem. Often, there is no real story to speak of, with many works simply stating facts regarding their fictitious ecosystems and life-forms, like a field guide or documentary.

Speculative biology is very popular online among amateur biologists, worldbuilders, and animal fans, especially on sites like Deviantart and Reddit. This sort of work is also common in fandoms that feature fantastical animals; artists will invoke realism in their works and try to revamp the characters in a way that makes more biological sense. However, it's also a topic that gets professionally discussed. Several books and a few documentaries have also been created on the topic of speculative biology. Most works of speculative biology at least try to obey real-world laws of science and are (in theory) generally harder science fictions, and if any sort of supernatural Hand Wave is involved, Magic A Is Magic A will be in full effect. Indeed, providing real-world explanations for fantastical and fictional creatures (just how do dragons breathe fire?) is another popular form of speculative biology.

That being said, many works of speculative biology are not very biologically rigorous, even less so from works made by beginner worldbuilders just getting into the genre. Many artists end up coming up with inaccurate animals and circumstances that most likely couldn't occur. Every so often however, years later a species is discovered that resembles a previously fictional animal. It's also worth nothing that our ideas of what is biologically plausible and what isn't changes all the time.note 

These works often, but not always, take the form of a Speculative Documentary. Related to Fantastic Science and Bizarre Alien Biology. Subtrope of Worldbuilding.


    open/close all folders 

    Anime and Manga 
  • Delicious in Dungeon, despite being primarily a plot-driven Dungeon Crawler story, goes into great detail about the dungeon's ecology and how the monsters there function. For example, suits of Animated Armor are actually colonial mollusks with very specialized shells, each of which makes up one piece of the suit. There are also discussions of how a dragon's physiology works, with most of them usually asleep to conserve energy.

    Fan Works 
  • Chritopher Stoll, a Deviantart-based artist, does this with his two series, A Natural History of the Fantastic (which cover mythical creatures) and PokeNatomy (which covers Pokemon).
  • Fixing RWBY: The "History" video tries to explain the faunus in a bare minimal scientific manner. In contrast, RWBY canon just goes for a "The gods did it" answer. Faunus are related to humans through a common ancestor. They're closely enough related to interbreed with humans, but faunus have various behavioral and physical differences from humans.
  • The Pokédex - Extended Fanon Edition is a Just for Fun series on This Very Wiki that ratchets up the premise of Pokémon and documents the creatures as if writing a scientific article about real-world animals, dealing their biology, behavior, reproductive habits, diet and depiction in human culture.
  • Realistic Pokémon is a series of fanarts depicting interpretations of Pokémon as if they were, or had evolved from, real-life animals. Some, like Zapdos and the Eeveelutions, remain largely what they are in canon, albeit with more realistic anatomy. Others get more drastic redesigns — Giratina is interpreted as a giant insect native to extremely deep caverns (the Distortion World) where the air pressure is high enough for its larval form (Giratina's Origin Forme) to "swim" through the air. Likewise, Voltorbs are drawn as red-and-white armadillos that "explode" by violently uncoiling.
  • Tiny Sapient Ungulates is a realistic take on My Little Pony: Friendship is Magic:
    • The ponies themselves are a species of basal ungulates with short muzzles and big ears, as well as legs still ending in five digits tipped with hoof-like nails and with some limited mobility (explaining their in-show ability to hold objects with their hooves). Pegasus wings are reimagined as lobed wings of skin supported by elongated fingers like a bat's.
    • Griffons become hexapodal birds that evolved from solitary predators. As such, they only typically interact for territorial posturing or trade and are mentally predisposed to see all forms of interaction as one of these two, explaining their aggressive and greedy behaviors.
    • Changelings become enormous four-legged insects who evolved to mimic ponies (their food source) and that feed on both emotional energy and solid matter. Their transformation in "To Where and Back Again" is interpreted as Chrysalis essentially starving her hive by denying it both physical food (as she wrongly believed they didn't need it) and the social interaction they need for optimal feeding, only allowing them to grow into stunted neotenic forms. Thorax's takeover allowed them to start feeding properly again and morph into their true adult shapes.
  • Oceaniz's The Nature of Monster Hunter series is Exactly What It Says on the Tin: An in-universe documentary series analysing the many ecosystems of the Monster Hunter universe and the monsters that live within them through a scientific lens, up to and including Elder Dragons. There are two seasons as of writing: one focusing on the New World, and one focusing on Kamura. There are also several specials that take an in-depth look at other miscellaneous topics like monster sub-species and variants.
  • The Yeerk and the Gedd: A Natural History is an attempt to explain the evolutionary origins of the Yeerks and their natural hosts the Gedds, alien species from Animorphs.

    Film — Animation 
  • The Good Dinosaur presents a What If? scenario in an Alternate Universe where the asteroid that doomed the dinosaurs completely missed Earth and non-avian dinosaurs never became extinct and continued to evolve. The film itself speculates that after a few further millions years several species including Sauropods and Tyrannosaurs could evolve human-level intelligence and develop language, tool use and agriculture.

    Film — Live-Action 
  • After Earth sees an alternative future Post Apocalyptic Earth where humans evacuated the planet and all the animals have continued to evolve for a few thousand years (including baboons, condors, tigers and even whales).
  • Anonymous Rex imagines a world where dinosaurs didn't go instinct but instead evolved into humanoids who live among humans in disguise. The narrative occasionally references how different species of humanoid dinosaurs have evolved traits that are distinct from humans and other species of dinosaur.
  • Avatar explores the moon of Pandora, detailing its atmosphere, geography and biomes, as well as the flora and fauna. Surprisingly, the creatures of Pandora show an interesting amount of evolutionary relatedness in their anatomy, all sharing a "vertebrate" body plan of six limbs, four eyes, a pair of neural whips on the head and breathing holes located on their chests. Strangely however, the local sapient species, the Na'vi, defy many of these anatomical designs and are much more Humanoid Aliens.
  • King Kong (2005) presents a world where a population of dinosaurs and other prehistoric creatures that survived the KT event and have continued to evolve on Skull Island for a further 65 million years, the ecosystem and creatures are further expanded on in “The World of Kong: A Natural History of Skull Island” book.
  • Monsterverse takes a surprisingly scientific approach on its Kaiju, featuring the likes of Godzilla and King Kong in a more scientific light and portraying them as ancient superspeciesnote  from a more-radioactive Permian period. Granted, there is a lot of Artistic License – Biology regarding how such big creatures can live in Earth's gravity or how they can sustain nutrition from radioactive material, but nonetheless the series explores the behavior, ecology and biology of the creatures of Skull Island and the Hollow Earth in a way that portrays them like an actual ecosystem that once existed in nature.

  • All Tomorrows by C.M. Kosemen chronicles the evolution of various human descendants across dozens of planets over a billion years after some nasty intervention from the Qu, a malevolent godlike alien race. It can be read here.
  • Animorphs: In the prequel novel The Ellimist Chronicles, the Ketrans play a game that revolves around slightly modifying the conditions of their chosen virtual creatures' planet in order to influence their evolution towards a specific direction. Different players' creatures can even come into contact with one another through space travel.
  • Cryptozoologicon tries to reinterpret cryptids as plausible animals, although sometimes they choose a more creative interpretation rather than one that best fits the myth (such as making the Mbielu-Mbielu-Mbielu into a giant amphibious bichir).
  • Dougal Dixon is probably the Trope Maker of this genre. Many of his books center around using their fictional lifeforms and ecosystems to illustrate various concepts in biology.
    • After Man: A Zoology of the Future is a 1981 book on how Earth could evolve in the fifty million years after humans go extinct. The earliest and least specialized of the books, it simply uses its creature to depict the process of evolution and natural selection. It is one of the most famous and influential examples.
    • Greenworld is a 2010 book describing an entirely alien ecosystem, as well as its gradual collapse as a result of overhunting and habitat destruction by human colonists. It mainly illustrates the harmful effects of human exploitation on nature.
    • Man After Man: An Anthropology of the Future is a 1990 speculative fiction book that focuses on individual characters rather than whole species. It starts After the End in the 22nd century, when the Earth has been ruined by human overpopulation and destruction of the environment and the humans decide to launch spaceships to find other livable planets. Scientists created two humanoid species — the frog-like "aquamorph", and the "vaccuumorph" that only can survive in the airless voids of space — in order to help build the ships, as well as a species of gilled manatee-like humans. Other human descendants reverted to an animalistic state, becoming giant yeti-like herbivores and saber-toothed predators. It illustrates the concept of evolutionary radiation.
    • The New Dinosaurs: An Alternative Evolution is a 1988 book about how dinosaurs could have evolved over 68 million years if the mass extinction had not happened. Due to being made in the 1980s, the book is very outdated in many respects. It's used to illustrate zoogeography and biogeographic realms, where distinctive flora-fauna communities dominate large stretches of the Earth's surface alongside more isolate assemblages on islands and island continents.
  • Evolution: The last third of the book, "Descendants", describes the gradual evolution of the Earth and its organisms after the extinction of humanity. After a near-future age of feral posthumans, there is a Cretaceous-like period of titanic predatory rodents and animalistic human descendants adapted to fill the niches of monkeys and elephants, and much later the last gasps of a dying world and the strange creatures adapted to live in its empty deserts.
  • Quite possibly the first instance of speculative biology ever was by none other than Charles Darwin himself. After watching bears fishing, he hypothesized in On The Origin Of Species that in the future, bears might become more adapted to aquatic life and evolve into whale-like creatures note .
  • Expedition is a 1990 book by Wayne Barlowe about the biology, native lifeforms and ecosystems of the fictional planet Darwin IV. It was adapted into the TV movie Alien Planet by Discovery Channel.
  • Fantastic Beasts and Where to Find Them, the prequel novel of the famous book series Harry Potter, has more of a focus on the titular beasts and how their adaptations compare to their muggle counterparts.
  • The Flight Of Dragons by Peter Dickinson imagines how dragons might have existed, explaining everything from how such huge creatures could fly (they were basically living hydrogen balloons), how and why they breathed fire (once again, they were basically living hydrogen balloons) and why nobody's found any fossils (the internal chemistry necessary to be a living hydrogen balloon was so volatile they dissolved on death). This very loosely inspired elements of the animated film of the same name.
  • Fragment: Most of the action takes place an isolated island with a bizarre biosphere descended from Ediacaran and Cambrian life. However, much like Green Antarctica, it is a Death World strongly informed by Rule of Scary.
  • Many of the Humanx Commonwealth novels contain heavy doses of this trope, presenting alien ecosystems and sentients existing in a variety of Single-Biome Planet habitats. It helps that Alan Dean Foster is as much a biology-geek as a scifi-geek.
  • InCryptid explores the possible biologies of cryptids and mythical creatures, with a heavy dose of magic. Some of the ones that don't make sense with evolution on Earth are implied to have originally come from Another Dimension.
  • King Kong (2005) got a companion book called The World of Kong: A Natural History of Skull Island, where the biology of the various monsters, from the dinosaurs through the giant bugs to Kong himself, got described in a semi-scientific way. Hundreds of life forms that didn't make it onto the big screen are also presented, many of them in full-color artwork and with proper biological nomenclature.
  • Known Space: Niven often uses this trope. The Ringworld sub-series in particular explores the many potential hominids that Homo habilis might have diversified into, given unlimited space, no predators, and a variety of vacant ecological niches to occupy.
  • The Long Earth series explores parallel Earths, including ones where hominids developed along different lines or where other animal lineages developed intelligence instead.
  • Steve Alten’s Meg central premise is that megalodon had not gone extinct but rather evolved to live in the deepest part of the ocean — the Mariana Trench, surviving for millions of years and into modern times, evolving to breed asexually with such low populations and losing pigmentation in their skin in the abyssal waters. Many species of marine reptiles like pliosaurs, ichthyosaurs, giant sea turtles, and mosasaurs also managed to survive by all evolving gills.
  • A Memoir By Lady Trent describes a Low Fantasy world with largely the same culture and animals as real life, but also home to very diverse dragons. The dragons are given extensive analysis through the character of Lady Trent, a naturalist dedicated to studying their taxonomy, anatomy, behaviors and ecology.
  • The Mote in God's Eye: One of the plot elements is how the various subspecies of Moties evolved. Determining how this occurred is crucial in determining that some of the Motie bodies ejected from the Crazy Eddie Probe are Warriors, which exposes one of the Moties' darkest secrets.
  • Rust And Humus is an extremely unique case in that it is also High Fantasy. It is pretty light on biological accuracy because of its surrealist tones, but it does closely follow evolutionary paths of the various life forms it chronicles.
  • The Snouters: Form and Life of the Rhinogrades, by the German zoologist Gerolf Steiner in 1957, may be one of the earliest semi-serious examples, as the book documents the bizarre endemic inhabitants of a fictional island chain, cartoonish shrew-like creatures that have evolved to do every conceivable activity with their noses (walking, eating, jumping, swimming, reproducing etc.). Despite the absurdity of the subject, the snouters are treated with absolute seriousness and strict scientific rigour.
  • Tales of Kaimere is a low-fantasy universe where prehistoric animals from different time periods come to coexist in a fantasy world. Derived theropod dinosaurs called megaraptorans take the role of "dragons", large derived giraffids are "unicorns", and a wide variety of other fauna, such as hyena-like entelodonts, flightless ape-like pterosaurs, and manatee-like aquatic dicynodonts, to name a few.
  • What Does a Martian Look Like?, by Jack Cohen and Ian Stewart, imagines how alien life might evolve, including a lengthy speculation on how tribbles might actually work.

    Live-Action TV 
  • Alien Worlds (2020): The series alternates between describing real-life processes and events in the natural world, such as sexual selection, hunting behaviors and mass extinctions, and attempts to use this knowledge to model imagined alien ecosystems and describing the ecologies and life cycles of alien organisms.
  • Cosmos: One episode has Carl Sagan discussing a theoretical ecosystem on Jupiter in which the animals had evolved into Living Gasbags in order to cope with the planet's conditions.
  • Dinosapien asks "what if non-avian dinosaurs hadn't gone extinct?" and goes with it. In it, an earthquake opens up and reveals a Lost World where dinosaurs survived the mass extinction and evolved for a further sixty five million years. The show specifically features two species, Eno, who is a species descend from dromaeosaurs and the Diggers, a pair of aggressive semi-bipedal Pachycephalosaur/Ankylosaurids.
  • Doctor Who: "The Lazarus Experiment" has Richard Lazarus being mutated into a fearsome giant centipede/scorpion-like monster after an experiment with an anti-ageing machine goes wrong. The Doctor describes the monster as a creature of evolutionary potential — something that evolution could have turned humanity into if it hadn't gone the "two arms and legs, ten fingers and toes" route — lying dormant within Lazarus' genes.
  • Dragons: A Fantasy Made Real is a 2004 mockumentary where the remains of dragons are discovered in a cave. It goes onto describe how different dragon types could have evolved, how they would have worked, and why they went extinct.
  • Extraterrestrial (2005) describes imagined alien environments on two alien worlds, using them as ways to exposit on natural processes and on the possible nature of extraterrestrial life.
  • Future Cat is a documentary discussing how big cats could evolve in the future. It's also briefly mentioned that smaller cat species could start going underground, similarly to foxes.
  • The Future Is Wild is a 2002 Animal Planet documentary. It is a Spiritual Successor to the speculative evolution book After Man: A Zoology of the Future. In contrast to the book, the documentary says that humans simply left to live on another planet rather than went extinct. The documentary has been criticized for containing animals that are implausible, such as a giant land squid millions of years into a future where mammals have died out and other species fill their niches. Nonetheless, the documentary has a solid cult following, and was popular enough to warrant a spin-off children's show courtesy of Nelvana, which is something one can't really say for most of the other Speculative Biology works on this page.
  • Life After People wandered into this occasionally, most notably when it posited that descendants of the domestic house cat might, in adapting to hunt birds in the decaying remnants of vine-choked empty skyscrapers, evolve skin-fold parachutes like a rudimentary version of a flying squirrel's.
  • Mermaids: The Body Found is a 2012 mockumentary and is the Spiritual Successor to Dragons: A Fantasy Made Real. It describes how a species of ape could have evolved into an aquatic animal, eventually becoming mermaids. Unlike its predecessor, it is a Found Footage Film. It's most famous, though, for being mistaken for an actual documentary when it aired, since the disclaimer that it was a work of fiction was hard to see.
  • Natural History Of An Alien, also known as Anatomy of an Alien in the US, is a Discovery Channel series with a green alien viewing various theoretical ecosystems including the depths of Europa's oceans and a planet with 1.5 times Earth's gravity to the world of Greenworld created by Dougal Dixon and Helliconia created by Brian Aldiss.
  • Primeval dips into this, with creatures from the far future (including expies of creatures from After Man: A Zoology of the Future) alongside those from the distant past that were never preserved in the fossil record.
  • Through the Wormhole: One episode is about how aliens could realistically look like depending on the planet they are from.

  • Tides is mostly a showcase of the lifeforms inhabiting the ocean moon Fons, recorded from the perspective of a xenobiologist stranded on its surface by a freak accident.

    Tabletop Games 
  • Traveller: When the game was first created, a key part of the design of its alien races was deciding not just how they evolved, but how they developed intelligence.

    Video Games 
  • The Eternal Cylinder explores the biology and life cycles of the native wildlife of the Trebhums' home planet in the flavor text. Highlights include the close evolutionary relationship between the Tripoboosh and the Onogrosh as being tundra and desert variants of a common ancestral species, the complex life cycle of the metamorphosing Tonglegrop, or the omnivorous Omnogrom with blunt teeth designed for durophagy. Some creatures, however, cross over to outright fantastical elements such as the Zooshgarg, which floats in the air and hunts by literally manipulating gravity, or the protagonist Trebhum who can mutate instantly by eating various food.
  • Evolution: The Game of Intelligent Life: Animals can evolve into fictional or speculative species, like intelligent elephants, parrots, wombats, or dinosaurs.
  • In Other Waters follows a xenobiologist exploring the oceans of the exoplanet Gliese 667 Cc, documenting its many bizarre species. Their notes, unlocked via observing creatures and collecting samples to analyze, go into quite a bit of detail regarding the anatomy, ecology and behavior of the local wildlife.
  • Metroid Prime Trilogy: Scanning enemies and other alien lifeforms gives biological and behavioral details about them.
  • The Pikmin series is best known for its dabbles in this in the enemy entries in the Piklopedia, with Olimar's notes giving them scientific names, attempting to classify the alien beasts into taxonomic families (such as the Mandiblard family, the Arachnorb family, the Grub-Dog family and the like), and describing and speculating on their behavior and ecological relationships with other species. In Pikmin 3, Alph adds his own observations on the creatures anatomy and physical structuring. Louie's notes, however, are just all about cooking them. Again, some of the creatures' hunting and defense mechanism border on fantastical elements such as Creatures like Gatling Groinks and Careening Dirigibugs hunting by creating bombs, Jellyfish-like creatures that can fly without any apparent parts to assist flight, and all the final bosses, barring the Emperor Bulblax in the first game, either literally using man-made weapons as both hunting and defense mechanisms such as the Titan Dweevil, or near-otherworldly powers, such as a near-Eldritch Abomination creature that can split itself apart to create copies of other animals and hazards like the Plasm Wraith.
  • Pokémon occasionally dabbles in this, mostly through PokeDex entries that detail the creatures' biology. The Alola games specifically go into detail on the hunting habits of Pokémon. However, they're just as likely to go for Rule of Cool, and most of the "science" they contain is pure nonsense. Then again, this is a universe where almost every animal has Elemental Powers, and "egg groups" completely invalidate the very definition of a species, so it's obvious realistic biology doesn't really apply in most cases.
  • The Sapling is about creating plants and animals that can survive in certain environmental conditions. The player can edit their creations, or let the game randomly mutate them in sandbox mode.
  • Spore: The game's original premise was the creation of alien species, and making them adapt to the environment and evolve into sapient beings. However, it changed direction mid-production, leading to more cartoonish and unrealistic gameplay and art style.
  • Subnautica delves into this at times regarding Flavor Text surrounding the various marine alien life you encounter, some of which is used to justify gameplay behaviour (such as the Stalker eating scrap metal because it incorporates the material into its teeth to harden them). Of course, this being a video game first and foremost, Rule of Fun trumps scientific rigour here.

    Visual Novels 
  • South Scrimshaw deals with strange sea creatures on the world of Aria, where all life is descended from Ultraterrestrials transplanted there long ago. The main story focuses on Brillo Whales, a cetacean species notable for being able to implant various objects and organisms onto their bodies to gain different abilities, with the main character being a calf learning to survive in this alien ocean.

    Web Original 
  • Alien Biospheres is a series of videos by Biblaridion dedicated to detailing the evolution of life on an alien planet. The two predominant groups of lifeforms in the series are the shelled cephalopod-like tentaclostomes and the spider-like sarcopods.
  • Athyrmagaia by Batterymaster is an alien world dominated by the Athyrmatherians: a clade of typically hexapodal animals that resemble Earth animals at least visually, such as the bovine-like mock oxen, the wolf-like steppe fenrir and the lion-like emperor zouyu. But what makes these creatures truly unusual is the fact that each animal is actually formed from four separate animals that fuse together with their siblings to form a composite: with some species even having two separate adult forms: one where a single larva matures on its own, and one where four of them assemble to form a composite adult.
  • The tumblr paleoartist Alphynix has a month-long event in 2020 called "Spectember", dedicated to speculative evolution art (using ideas submitted by fans on Patreon) with weekly intermissions discussing the history of spec-evo as a genre. Several of their entries have included flying frilled lizards, carnivorous ceratopsians, and terrestrial cetaceans inspired by the below-mentioned Delphinus Archipelago, to name a few.
  • Amphiterra by Javier Valdez, is an experiment dealing with an alternate timeline where frogs, instead of mammals and reptiles, colonized the earth at the beginning of the Triassic period from the ancestral amphibian, Triadobatrachus. While the early descendants resemble frogs of today, they quickly become a wide array of forms, such as barnacle-like sessile filter-feeders, arctic grazers with an insulating coat of secreted foam, or giant T. Rex-sized apex predators, as well as two sapient species that evolve 65 million years apart from each other.
  • Antarctic Chronicles is a project by Reddit user u/RisingMagpie exploring the colonization of Antarctica by flora and fauna, as it warms up and drifts closer to the equator.
  • Astrobiologica, also called the Wallace Project (at least in the first episode; this alternate name isn't mentioned afterward), is about the binary planetary system of Ecco and Xea orbiting the twin stars Wallace (a yellow star like our Sun) and Sarowak (a smaller red dwarf) in a figure-8 pattern. As alien life emerges on the predominantly oceanic planet of Ecco, the barren world of Xea is settled by humans and Earth life. The series notably uses pixelated imagery reminiscent of 16-bit games from the early 1990s.
  • Bosun's Journal describes the speciation and evolution of posthumans on a lost Generation Ship, beginning with a caste culture of genetically engineered humans, then a post-apocalyptic age of posthuman animals descended from the earlier castes, and eventually the reemergence of higher intellect.
  • The Delphinus Archipelago, a Tumblr project about the evolution of land dolphins that started with a criticism of the hideously inaccurate Titan Dolphin from the cancelled The Future Is Wild virtual reality game by Tumblr user Alphynix and was expanded on by various others. It features the evolution of dolphins that become terrestrial, modifying their tails and foreflippers into three hoofed legs, and evolve into a wide variety of forms, ranging from mostly-conservative seal-like forms, to truly absurd forms such as giraffe-like browsers, furry squirrel-like rodent-analogues, and a unicorn-like apex predator that chops its prey apart with its horn (even having a scientific nomenclature named after Guiron).
    • The project was later added upon by Alphynix, adding long-necked brontolphins and herbivorous dolphalopes, and a further installment introduced the beaked dolphins with bird-like bills, which included mole-like burrowers, azdarchid-like ground hunters and even a gliding arboreal species.
  • Played for Horror with Green Antarctica, a work that details a whole ecosystem evolved from penguins, marsupials, sloths, monkeys, and other Gondwanan animals. However, many of the details are informed by Rule of Scary, and/or are inspired by H. P. Lovecraft.
  • Har Deshur: Visions of an alternate, slightly more habitable Mars tries to explore what alien life on the surface of Mars might be like, if conditions had remained more stable and if predictions from before Mariner-4 had turned out to be true. While complex, multicellular life does now exist on the surface in this reality, most of it is small and adapted to extreme conditions. Also acts as an homage to many earlier speculations about life on Mars. Glimpses of the other alternate planets in the solar system are given on occasion.
  • Jurassic Impact is alternate history by Reddit user u/EpicJM that explores the evolution of fauna in a world where the asteroid that killed off the non-avian dinosaurs hit in the Late Jurassic rather than the Late Cretaceous in our timeline.
  • Life Around a Red Dwarf by Project Rose is a speculative biology project dealing with three Tidally Locked Planets orbiting a red dwarf star called Roseus, loosely inspired by the real life Trappist-1. The first season focuses on Nusku, the planet closest to the star and the most Earth-like of the trio. The creator says the idea and format were directly inspired by Alien Biospheres.
  • DeviantArt artist ElSquibbonator gives us The Neozoic, a long-form project revolving around the evolution of life on Earth over the next 100 million years.
  • Planetcopia downplays the biology part in favor of focusing on general climate and geography of imagined worlds. These worlds include our own Earth if it got tilted in such ways as to reposition the poles, ice caps, and latitude distribution of the continents (one called Jaredia is inspired by Jared Diamond's Guns, Germs, and Steel and tilts the world to give it the largest possible east-west continent extension); Mars and Venus after a thousand years of Terraforming; and more alien worlds with very un-Earthlike land/sea ratios and distributions. The actual biology consists of transplanted Earth creatures and/or straightforward Intelligent Gerbils, since the focus is more on how Earthlike organisms would adapt to weirder environments.
  • Polinices is an art project by J. J. Aniorte that deals with a planet where harsh solar radiation leaves the surface uninhabitable but which has many strange asymmetrical and/or colonial organisms in its oceans.
  • Planet Cat Sanctuary is seed world projact by Reddit user u/ExoSpectral that focuses on cats evolving on a seed world. To feed the cats, mice, rabbits, sparrows and lizards are also introduced into the planet, and they evolve alongside the cats.
  • Sagan 4 is a web project about creating an entire alien ecosystem that evolved from a single unicellular life form, inspired by discussions of the game Spore which was then in production.
  • Dylan "Sheather" Bajda has made this genre his specialty:
    • Serina is a web project that takes place over 250 million years on Serina, a fictional terraformed moon where a number of plants, algae, microscopic organisms and invertebrates were introduced, but only 8 vertebrates: 7 tiny fish (guppies, mollies, swordtails and platies) and only one tetrapod: the domestic canary. Over millions of generations, the canaries produce a bizarre array of species, resembling dinosaurs, mammals, reptiles and eventually even resembling insects and fish, while the guppies colonize the land and become analogues of amphibians, reptiles and mammals.
    • Sheatheria, a bizarre alien planet that defies the laws of physics: it has an equatorial ice cap separating the north and south hemispheres, and is three times bigger than Earth but is less dense and thus has the same gravity. On the planet, various Earth lifeforms, from different geological eras from the Cambrian to the Permian to the Mesozoic to the Cenozoic, are introduced at intervals, and evolve alongside other creatures they never coexisted with during their time period.
    • Pluvimundus focuses on the titular alien planet where the alien animals have evolved to be rather convergent with Earthly tetrapod life...but not quite. Most notably, the "birds" are most closely related to the "mammals", with beaked feline predators and hand-standing "pterosaurs", as well as a sapient species resembling small, green-furred lemurs. It is largely a rework of Sheatheria, using most of the same animal groups.
    • The tongue-in-cheek An Ordovician Tomato, where a time traveling accident sends a tomato back 479 million years, before there were even any land plants, and starts a parallel timeline that resets the history of all life on Earth. Sadly, the project appears to have been deleted from the internet completely.
  • Snaiad is a project by C.M. Kosemen, author of All Tomorrows, envisioning "vertebrate" life on an alien planet. All of these creatures have two heads, neither of which contains the brain - that's located in their chests.
  • The Speculative Dinosaur Project is a modern-day Spiritual Successor to the 1980s book The New Dinosaurs: An Alternative Evolution. It's a speculative biology project on how dinosaurs could have evolved if the K/PG mass extinction had not occured.
  • Natural history Youtuber Ben G. Thomas does an excellent three-part history on speculative zoology that can be viewed here.
  • Tlaquanaru by avancna is essentially an alien planet where life forms evolved very convergently with earth's, essentially acting as an alternative evolution project as well. There are analogues for mammals, lizards, dinosaurs, mosasaurs among many groups, but looks can be deceiving: the "lizards", for instace, are more closely related to "mammals". It is in many ways a precursor to Dylan Bajda's Pluvimundus mentioned below.
  • The Youtuber TREY the Explainer usually focuses on actual paleontology; however, he has dabbled with this:
    • He once did a video on what he thinks aliens would actually look like. He is very much against the prevalence of Humanoid Aliens and The Greys in media.
    • In his videos on debunking cryptids, he discusses near the end what he believes they hypothetically would realistically be. For example, in his video on the Loch Ness Monster he speculated that it wouldn't be a plesiosaur but instead would be a giant leech.
    • Likewise, his video on The Flatwoods Monster ends with the theory that it would be a giant salamander, rather than an alien.
  • Tribbetherium's projects:
    • Hamster's Paradise: Concerns a seeded world, where the colonist animal of choice is the Chinese dwarf hamster, introduced to a planet with Binary Suns and a habitable biosphere by human colonists who then abandon the planet and leave them to evolve for 500 million years. The project is Reference Overdosed, featuring creatures such as hopping kangaroo and wallaby-analogues called the boingo and the oingo, a saber-toothed big-cat-like predator called the jeggo, a diverse clade of flying rodents called ratbirds, two reptile-analogue "ratptiles" at different geological ages called the fastoise and the baryzard, and a sapient race of humanoid ape-like rodents called the mousey micks.
    • Planet of the Pseudosnakes, an earlier project by Tribbetherium, features a parallel evolution on Earth in which the land ended up being conquered not by lobe-finned fish, but by an unspecified eel-like bony fish lacking paired fins entirely. These become a group of terrestrial, limbless snake-like forms, which diversify into clades such as the snogs (monopedal frog-like hoppers), theriodontophidians (serpentine analogues of mammalian carnivores), and the arboreal twintrunks, among which is a sapient species that makes homes out of living trees.
  • A World of Dinosauroids, a speculative evolution project by C.M. Kosemen and Simon Roy set in an alternate timeline where the K-Pg event did not happen, where a few species of sapient troodontids call the planet home. The societies and fauna of the world is also shown in great detail.

    Western Animation 
  • How to Train Your Dragon sometimes dabbles in this, displaying different types of Dragons as different species with a couple overlapping traits, implying that they evolved from a common ancestor. This is most prominently shown in Book of Dragons which describes at least 6 major taxonomic families of Dragons that most dragons in the franchise belong to.