Transplanted Aliens

These are alien species that have established multi-generational communities on a different planet from where they originated, effectively ending up as native to their new home. These aliens might wind up on this new planet in a number of ways such as: getting dumped there by another spacefaring species or being transported through an interdimensional portal.

Overlaps with Alien Animals if an entire animal species thought to be of Earthly origin turns out to be this. If humans turn out to be the transplanted aliens, then it's Humanity Came from Space while Transplanted Humans would be the reverse situation. A general way to distinguish this from panspermia is that while the latter explains the origin of a planet's entire biosphere from a sample of extraplanetary life, this is more along the lines of aliens integrating into a preexisting ecosystem. May result in an Introduced Species Calamity if the transplanted species don't play well with their new environment.

If the aliens colonized a new planet on their own without some other force's interference it's Settling the Frontier, a Lost Colony if the colony's existence has been forgotten. Transplanted Humans do not include human colonies established by human means so we hold non-humans to the same standard.

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Examples

Anime & Manga

• Gate: All of the races on the other side of the Gate had come through the Gate at Alnus at one point or another, as the goddess Hardy would open it to various worlds at intervals to stir up social changes and development.
• Goblin Slayer: The goblins are speculated to have originated on another world, but crossed over to the human world via a portal.
• Nadia: The Secret of Blue Water: Attempted by the Atlantes when they brought animals to Earth from their own planets in their arks. The protagonists find some skeletons in these arks.
• Robotech had a series of novelizations of the series that also went beyond what was televised. One of the revelations of the novels is that the "Invid flower of life" and the Pollinators were, in fact, originally from Earth, which is why they flourish so readily in the Mospeada segment when they're reintroduced to our world.

Film — Animation

• Doraemon: All over the place in the movies:
  • Doraemon: Nobita and the Steel Troops: The titular Steel Troops hails from Planet Mechatopia, a world where all their inhabitants are robots. When an injured Robot Girl named Riruru comes under Shizuka's care and Shizuka enquires "someone must've created your kind", Riruru reveals their ancestor to be a human scientist who fled from his dying planet to an empty world, and created the robot equivalent of Adam and Eve 30,000 years ago.
  • Doraemon: Nobita and the Winged Braves: Doraemon and gang visit Birdopia, a parallel world accessible by a wormhole ruled by andromorphic, humanoid birds. They found out at the end that it was created by a 23rd-century scientist and ornithologist named Mamoru Torino, who hates humans and travels to another reality with his hundreds and hundreds of avian pets, arriving in an empty world where he then accelerates evolution in the birds using an Evolution Ray. Thousands of years later into the present, the sentient birds now have their own community and culture.
  • Doraemon: Nobita in the Wan-Nyan Spacetime Odyssey: An accidental example. Nobita and friends come across a pack of stray cats and dogs and decide to bring them to a time before the existence of humans, 300 million years ago, with Nobita using one of Doraemon's Evolution-Accelerating Gadgets on the animals. The gang leaves for the present, with Nobita promising to return the following day, but their next Time Travel trip hits a snag when they're caught in a time warp, leading them to 299,999,000 years back - a millennia off the mark. And then they discovered the sentient dogs and cats have established their own bustling city.
  • Doraemon: Nobita and the Animal Planet have Doraemon and friends visiting the titular planet, a World of Funny Animals whose animal ancestors used to be from a once-glorious neighboring human planet destroyed by pollution and mass deforestation centuries ago, where a human scientist then decide the animals deserves a second chance, and transports selected populations of animals via a futuristic portal made of gas. The gas' effects, combined with the planet's environment, allow the animals to evolve and become sentient in generations to come.

Film — Live Action

• In Alien Nation and its spin-off series, the Tenctonese (aka the Newcomers) are a group of enslaved humanoid aliens whose transport ship crashlands near Los Angeles, so they integrate into the local population.
• Star Trek: Insurrection: A Starfleet Admiral attempts to transplant the Son'a to another planet, but the attempt is ultimately foiled, and the Son'a return to their homeworld.

Literature

• All Tomorrows: At one point, spacefaring posthumans discover a dinosaur fossil on a planet where all the other creatures were clearly alien.
• Animorphs:
  • The Yoorts are descended from Yeerks who were brought to another planet by an unknown civilisation.
  • Broccoli is revealed to be an alien plant brought to earth in the Cretaceous. The aliens didn't survive, but the plant did.
  • The Chee are a "race" of robots built by the extinct Pemalites, who fled to Earth before they died of a Synthetic Plague. The Chee combined the Pemalites' essence with wolves, creating dogs, and have lived on Earth since the Stone Age.
  • A small colony of escaped Hork-Bajir (brought to Earth as Yeerk slaves) live in a secret valley on Earth, and after the war, they seem to have come to an arrangement with the US government similar to Native American tribes.
• Dune: One obscure fact about the famous sandworms is that they aren't actually native to Arrakis, having been introduced to it from another world by parties unknown. Arrakis's inhospitable desert landscape is the result of an ecological collapse perpetrated by the worms' life cycle, in which their larvae encyst all liquid water deep underground. In the later novels, the Bene Gesserit begin transplanting worms onto other planets in order to prevent the Spice they produce from disappearing after Arrakis is destroyed.
• Ringworld: The titular Ringworld was built and colonized by a different branch of the pak evolutionary path that evolved into several thousand sapient and non-sapient species. One of the sapient species then went on to develop spaceflight and transplant primitive populations of other alien species found in the setting such as bandersnatchi, kzinti, and martians to the Ring.
• Planet of Adventure: Of the five intelligent species (including Humans) on the planet Tschai, only the Pnume are native to the planet. The others had invaded or been brought as slaves at different times in the planet's history.
• Star Wars Legends: In order to explain the very wide variety of sapient and nearly-sapient beings living on it in spinoff material, Endor is described as something of a lost island in space, as the nature of hyperspace around it has drawn an unusually high number of interstellar wrecks to its metaphorical shores. Of the beings found living there by the time of the movies, only the Ewoks, their Dulok cousins, the long-legged Yuzzums, and the fairy-like Wisties are local natives. Sharing the moon with them are well over a couple dozen other species, descended from the crews, passengers, and/or slave cargoes of ancient ships whose wrecks occurred so long ago that few of them now remember that they came from other worlds at all.
• The Stormlight Archive has alien wildlife that apparently occupied the world of Roshar before humans were brought over, though there are also more familiar species such as horses, pigs, cats, and birds that must have arrived with the humans.
• Tales of Kaimere: On a planet called Kaimere, which is about 50 light-years from Earth, a bizarre "alien" intelligence, composed of microorganisms that evolved on Kaimere itself, has harvested Earth life forms through portals since the Devonian, and has continued to do so until roughly present times. The result is an incredibly diverse ecology and evolutionary history, where groups of Earth's organisms evolved and then met new arrivals from earth, which then continue to co-evolve. Dinosaurs, mammals (including basal groups), and many others populate this ever-evolving world. One of the recent arrivals were a group of humans from North Africa, which have developed their own culture and history in Kaimere.
• The Witcher has a cataclysmic event in the backstory called the Conjunction of the Spheres when various races and creatures were transported to the setting from other dimensions.

Live-Action TV

• Defiance: Earth has become the reluctant home to a group of different species called the Votanis Collective, whose arrival drastically altered Earth's climate and flooded it with a whole lot of extraterrestrial creatures. The series deals with the humans and the Votans struggling to live together despite differing ideas and values.
• Star Trek: The Next Generation: In "Homeward", the Enterprise helps relocate a group of aliens native to Boraal II to another planet because their homeworld has become uninhabitable. Unusually, the aliens aren't aware that they have been transplanted; Worf's adoptive brother Nikolai helps trick them using holo-technology into thinking they're travelling on foot.

Tabletop Games

• BattleTech:
  • Clan Ghost Bear gets their name from a large arctic bear-like predator native to the Clan homeworld of Strana Mechty. When they abandoned the Clan homeworlds in the late 3050s, they brought many ghost bears with them and introduced the species to their new capital world of Alshain.
  • Clan Sea Fox initially named themselves after a seal-like aquatic predator native to Strana Mechty, which was rendered extinct in the wild by genetically engineered diamond sharks created by Clan Snow Raven in 2985, and Clan Sea Fox temporarily renamed themselves Clan Diamond Shark as a result. However, they secretly bred sea foxes in captivity and released them on multiple Inner Sphere worlds, reclaiming their old name in 3100.
• Coriolis: The Third Horizon: The Horizon’s native intelligent lifeforms were at a stone age level of technology when humans arrived and are treated like animals by most of the factions, leading traders to export them to several planets. Nekatra in particular are found on so many planets that nobody can tell which is their homeworld, or if they were transplanted by humans or the portal builders.
• Empire of the Petal Throne. After the planet Tékumel was terraformed by explorers from Humanspace, it was settled by humans and their alien allies. After the planet was cut off from the rest of the universe, it became their new permanent home.
• Numenera includes alien life forms that were apparently transported to the Ninth World by extraterrestrial and extradimensional civilizations that conquered the planet and then departed in the backstory.
• Pathfinder: The land of Numeria has aliens and advanced technological artifacts as a result of a spaceship crashing there millennia ago.
• Traveller:
  • The planet Urunishu is the site of an Ancient zoological park. Three hundred thousand years ago, the Ancients transported a large number of Earth animals there. When the Ancient civilization ended, the animals were released from the park and eventually adapted to the planet.
  • The Ancients also transplanted humans to multiple planets, but they're their own trope.
  • The Vargr were engineered from wolves and other canines by the Ancients and dropped on a distant planet called Grnouf in most Vargr languages, usually translated as "Lair."
• Warhammer: The Greenskins — orcs and goblins — are said by some of the fluff to have been accidentally introduced to the planet as spores that hitched a ride on the Old Ones' starships.

Video Games

• Borderlands: The Pre-Sequel! reveals that Threshers, tentacled worm-like creatures that first appeared on Pandora in Borderlands 2, are an invasive species originating from Pandora's moon Elpis. A side mission midway through The Pre-Sequel! has Sir Hammerlock ask Jack's Vault Hunters to send a pair of Threshers down to Pandora so he can study them, with the implications that the Threshers would go on to escape into the wild sometime between the two games.
• Ecco the Dolphin: Crustaceans and arthropods are devolved descendants of the Vortex that remained on Earth after Ecco defeated them in the original game and then averted the Vortex Future and repaired the time stream after the queen followed Ecco to Earth and the Vortex escaped into the distant past in Ecco: The Tides Of Time.
• Final Fantasy XIV: In Shadowbringers, several species of creatures and a number of Elite Marks were brought from the Source to the First by the arrival of the Crystal Tower. Once the tower's gates were opened, the freed creatures raced into the wilderness, after which they became part of the natural ecosystem.
• Half-Life 2: After the portal storms that caused creatures from the extradimensional world Xen to be brought to Earth, most of Earth's wildlife has been thoroughly replaced by the alien lifeforms, possibly killed off by either them or the ruling Combine army. Headcrabs, barnacles, and antlions are everywhere, just to name a few, and the player never sees any normal animals other than birds. Crabs and a single cat are mentioned, and fish, dogs, and rodents can be heard but not seen. Monkeys controlled by headcrabs are also found, and Half-Life: Alyx shows that cockroaches still exist.
• Mass Effect:
  • The drell race originally came from the arid planet Rakhana, but overpopulation caused it to fall into ruin. Fortunately, the hanar were able to save 375,000 (out of billions) of them and take them to their own planet Kahje. Most drell voluntarily serve the hanar in some fashion due to the fact they owe their existence to them. Unfortunately, Kahje is a humid planet and, while perfect for the aquatic hanar, is less than suitable for the drell, who evolved to live on their own arid planet. As a result, they are susceptible to serious illness, including a fatal bacterial lung disease called "Kepral's Syndrome".
  • The Thresher Maw, despite being a huge worm-ish bug thing has been transported unintentionally to many planets, as they reproduce through tiny spores that can be carried by unsuspecting spaceships on interstellar journeys. The biggest worm, said to be the ancestor of them all, comes from Tuchanka, explaining why they're so tough.
  • Varren are a species of aggressive predatory aliens that look vaguely like a cross between a dog and a deep-sea fish that are native to Tuchanka and have been intentionally introduced to a number of other planets by the krogen (and later batarians) as both a beast of war and food source.
  • Pyjaks are small monkey-like creatures that are known for spreading around easily because of their habit of stowing away on transport ships. They're a pest species pretty much everywhere due to their habit of getting into everything, stealing or fouling food stores, and breaking equipment. They're one of the few creatures that was accidentally introduced to Tuchanka and turned out to be adaptable enough and reproduced quickly enough to thrive there.
• Metroid: Occurs to multiple species:
  • The so-called Zebesians, the most common breed of Space Pirates in the 2D installments aren't natives of Zebes, but conquerors that claimed this planet as their own.
  • The logs in Metroid Prime 2: Echoes, which is set on the Rogue Planet Aether, make it pretty clear that the inhabitants of Aether, the Luminoth settled down there, but it isn't clear from where they come. As they say, "It is told that the Luminoth were not born of Aether but of the stars."
  • The Chozo settle many planets such as Zebes (seen in Metroid, Super Metroid, and Metroid: Zero Mission), SR-388 (seen in Metroid II: Return of Samus and Metroid: Samus Returns), Tallon IV (Metroid Prime), Elysia (Metroid Prime 3: Corruption) and ZDR (Metroid Dread). The original birthplace of the Chozo, however, is unclear.
• The Mother series has some ambiguous examples, particularly the Mr. Saturns. Also hinted at with the strange Gabilans, which are described as something that shouldn't exist on Earth.
• Pokémon: Certain Pokémon are said to have come from outer space, such as the Clefairy and Elgyem families.
• Przygody Reksia: The space hens, which are usually green in color, are a common sight on Planet Kuran. However, they were brought to the planet, which was previously only inhabited by moles, relatively recently
• Spore: The process of terraforming a world requires the player to gather species of flora and fauna from inhabited worlds and transplant them onto ones that may or may not have their own inhabitants, resulting in many worlds being populated by creatures who originated elsewhere. Sometimes, the player will also encounter offshoots of their own species on other worlds, presumably planted there by other terraforming civilizations.
• Knights of the Old Republic II: The Sith Lords: The Telos Restoration Project is a massive terraforming effort by the Republic to make a planet glassed by the Sith during the preceding Jedi Civil War livable again. Part of the project involved importing cannoks from the planet Onderon as the predator in an artificial food chain; however, when Czerka Corporation secured part of the contract, they cheaped out on monitoring and the cannoks ran completely amok in their zones.
• Star Wars: The Old Republic: A lot of animal species exist on multiple planets due to being transported to and fro by spacefarers: for example nexu, which are native to Cholganna but are chronologically first encountered in the game on Taris, having escaped from zoos and private collections when the planet was bombarded by Darth Malak back in Knights of the Old Republic.
• World of Warcraft: After the draenei fled their homeworld of Argus to escape the corruption of the demonic Burning Legion, they arrived on the planet Draenor (the homeworld of orcs), where they stayed for centuries. They also brought with them some talbuk, an antelope-like creature native to Argus, that thrived in Draenor, becoming a viable food source for the native predators and a part of orcish culture (in fact, when they were first introduced during the "Burning Crusade" expansion, it was assumed they were native to Draenor; it wasn't until "Legion" that were retconned as being transplanted from Argus).

Web Original

• The premise of Hamster's Paradise is that human colonists terraformed a lifeless planet by introducing enough organisms to form a stable ecosystem, and then some Chinese dwarf hamsters as test subjects. For reasons unknown, humans didn't end up living on this planet, so life was left to evolve on its own.
• In Jix the Tarians transplanted an evolutionary ancestor species of the Ambis, Amblians, and Earth foxes onto at least two planets.
• Neopets has the Grundos, a race of aliens from a distant planet known as Doran. They were enslaved by Dr. Sloth and brought to Virtupets Space Station to act as his mutant army and labor force. The plot from there consisted of players adopting the Grundos. Since then, the Grundo has always been considered a proper Neopian race, and though most of them live on the moon Kreludor ^note which eventually was retconned into being their original home since the Virtupets story, they can be found all over Neopia and aren't treated as being out of the ordinary.
• Serina is a Speculative Biology project which follows this premise; an unknown party plants Earth species in the moon Serina — canaries, and things that serve as their food sources (insects, sunflowers, etc), and some fish. For the next several million years, the project follows how those species evolve into completely alien forms.

Western Animation

• Dungeons & Dragons The unaired (but later made as an audio drama) final episode revealed that the various species living in The Realm came from other worlds and were brought there by Venger, as portals opened up to return each of them to their homeworld after Venger's defeat and redemption.
• Inside Job: It turns out Myc the psychic mushroom's people arrived on Earth via an asteroid millions of years ago and migrated to Hollow Earth after some apes started eating them.
• Mighty Max: Max finds himself up against a powerful robotic beetle named Beetlebrow which seems be attacking at random and drawing thousands of beetles to it. Turns out the beetles themselves are stranded aliens who crashed in the time of the dinosaurs and Beetlebrow is the robot they created to protect them. Beetlebrow has only reactivated because the rescue ship from their home planet is arriving and it's collecting the survivors for transport. Max is able to prove humans are no threat when one of the beetles shows him the movements needed to communicate non-aggression to the robot.
• The Owl House: Eda states in the first episode that giraffes were originally from the Boiling Isles, but were banished to Earth for being a bunch of freaks.
• South Park: Exaggerated in the episode " Cancelled", where it's revealed that every single species on planet Earth was actually put on the planet eons ago by aliens so they could broadcast the struggles of these species trying to live together on the same planet as part of a reality show.
• ThunderCats (2011): Most of the various animal peoples are revealed to originally have come from elsewhere as part of Mum-Raa's empire before his ship crash-landed on Third Earth millennia ago, long enough for them to have forgotten where they originally came from.

Real Life

• Real-world space agencies such as NASA go to extreme lengths to prevent this. Even though very little Earth life can survive for long in space, since many probe missions involve looking for signs of life or its chemical building blocks on other planets and moons of our solar system, it has become customary to repeatedly test components for the presence of Earth microbes during assembly and sterilize them, just to make sure samples (and possibly off-world biospheres such as might exist under Europa's glaciers) don't get contaminated.
• The Beresheet lunar lander, developed and built by the Israeli government and contractors, included a nickel wafer with a library microscopically printed on it that was provided by a private organization called "Arch Mission". Arch Mission did not announce that it had packed thousands of potentially-viable dormant tardigrades in between the layers of the wafer. Beresheet then crashed, scattering the wafer across the lunar surface. Arch Mission avoided legal consequences only because this happened on the Moon, which is mostly exempted from planetary protection rules because not even tardigrades can survive that place.

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