New Gaia Surface
Image from Anders Sandberg

Xenobiology is the study of non-Terragen life. This field includes the study of exotic and extremely non-terragen biospheres such as those that gave rise to the Muuh or the Soft Ones, and completely inorganic naturally evolved forms such as the Rheolithoids, as well as the descendants of xenobiological forms known to be partially or entirely of artificial origin, such as the life forms produced by the Halogenics, or the various Cybyotan worlds. Even the evolved mechosphere at Stanislaw has received attention from xenobiologists. Though only a few worlds rival the wealth of life forms present on Old Earth before the Great Dying, a single biosphere is still an entire field in itself from the point of view of ordinary sophonts, though comparative xenobiology is a rich field as well.

  • Abiogenesis, Lithopanspermia and Translocation  - Text by Steve Bowers
    Varying modes by which life may arise on a planet.
  • Animal  - Text by Stephen Inniss
    Strictly speaking, any member of a major group of related Old Earth organisms that are multicellular, eukaryotic, motile at some or all stages of life, and digest their food internally. More broadly, any similar biological organism, Terragen or otherwise, and natural or otherwise.
  • Barkbat  - Text by Todd Drashner
    A large predator, the barkbat clings to the trunks of the skywracks and uses its wings in a gliding flight to hunt other creatures that live in the canopy.
  • Bilateral Symmetry  - Text by M. Alan Kazlev and Stephen Inniss
    Any organism or device having symmetry along only a single axis (left and right), in contrast to radial or spherical symmetry.
  • Chlorine Worlds  - Text by Stephen Inniss
    Chlorine worlds are like typical Eugaian worlds, with one important difference: the planet has an unusually high proportion of chlorine, and the process of photosynthesis releases free chlorine in significant quantities.
  • Chorus  - Text by Stephen Inniss
    Homeworld of the xenosophont provolves the Jade Chime Singers.
  • Chorus - Xenobiology  - Text by Stephen Inniss
    Of the known Chlorine Worlds, Chorus has one of the richest and most diverse biospheres.
  • Conchsquid  - Text by Steve Bowers
    An apparently naturally evolved species of space-dwelling lifeform, confined to a single gas giant's ring system.
  • Cookie Fiend  - Text by John B
    A subsophont predatory lifeform native to the planet Elmo resembling a giant chocolate chip cookie with legs.
  • Cosmoamoeba, Giant Space Amoeba  - Text by M. Alan Kazlev and Oliver
    Cosmoamoeba gigas lagoonensis, one of the curious phenomena discovered in the Lagoon Nebula (and later in the Trifid Nebula) are a population of amorphous blobs that vary in size from 500 meters when contracted to several tens of kilometers when extended.
  • Cybyota  - Text by Steve Bowers
    Mechanical/biological world-seeding and terraforming agents of non-Terragen origin that have apparently evolved into independent life forms since their origin.
  • Deepwood  - Text by Todd Drashner
    Deep space orwood species of probable alien origin.
  • Devil's Rose  - Text by Todd Drashner
    Carnivorous xenobiotic plant.
  • Doreen/Doreens  - Text by Stephen Inniss, expanded and amended from original material by Anders Sandberg
    Chlorine world, former home of the extinct Doreens.
  • Duxed  - Text by Everything4404
    Garden World, a moon with an extreme tidal range.
  • Eden Institute of Xenoscience  - Text by M. Alan Kazlev
    A successful, respected, highly formalized and highly conservative Institute and academocracy, located at Niu Mynti. The Institute specializes in xenobiology, xenology, xenopsychology, xenodiplomacy and xenolinguistics, although it also covers many related disciplines. It collects information from all known alien biospheres and cultures, sending out expeditions to study new alien species and acting as consultants on all forms of Terragen-alien interactions.
  • Elmo  - Text by Steve Bowers
    Garden World in Monoceros, 1071 ly from Sol.
  • Exobiology  - Text by M. Alan Kazlev
    Also Xenobiology, Astrobiology. During the Atomic, Information and Interplanetary periods this was the speculative study of biology, biochemistry, and life forms on worlds other than Earth (at that time no non-Terragen life was known through direct contact). The termed was coined by atomic age scientist Carl Sagan. It is now very rarely used.
  • Exotic Biochemistry, Alien - Text by Anders Sandberg
    Although Non-Terragen biochemistries are rarer than terrestrial ecologies, they are not uncommon. Cold ammonia or methane ecologies are rarer, while chlorine, neutron star, free space or plasma ecologies are very rare.
  • Extremophile  - Text by M. Alan Kazlev
    A rather chauvinistic term for any biological organism, whether terragen or xenobiont, natural or tweaked, that requires extreme (non-Earthlike) environments for growth or metabolism.
  • Felis Minoris II  - Text by M. Alan Kazlev
    A cold planet altered by the unnamed species HIE236PPE (an extinct xenosophont race) so that it supports an ecology of cold-adapted lifeforms. These lifeforms share a common ancestry with those found on 12 other worlds.
  • Flitterhounds  - Text by Andrew P.
    Flying animals from Chorus.
  • Garden Worlds  - Text by The Astronomer, Steve Bowers 2020
    Worlds that support a complex biosphere and macroscopic life forms.
  • Grabgrass  - Text by Todd Drashner, Ryan B, and Mark Ryherd
    Carnivorous plant-form native to most of the temperate and sub-tropical regions of Ridgewell.
  • Hamilton Institute of Exopaleontology  - Text by Aaron Hamilton, M. Alan Kazlev, John M. Dollan
    One of the great scientific Houses of the Integration, the Institute was founded on the new University planet of Upali C/D II during the golden age of the 6th millennium, when relativistic exploration ships were increasingly encountering ancient and enigmatic ruins and relict tech of lost civilizations.
  • Hellswarm - Text by Todd Drashner
    A creature that combines all the less pleasant traits or aspects of terragen Africanized 'killer' bees, army ants, and locusts. On its homeworld, a hellswarm can strip a region of life as effectively as a major forest fire. The only defense is to either run away or burrow deep underground. Fortunately, the swarm is a short lived phenomenon, living only long enough to swarm, feed, breed, lay eggs in the soil, and die. The entire life cycle of the creature is only about 3 Terran days. The eggs may lie dormant in the ground for many years until environmental conditions (usually a warm, wet summer) triggers a mass hatching and a new hellswarm.
  • Honeywhip  - Text by Todd Drashner
    Carnivorous arboreal predator from the planet Trees
  • Invertebrate  - Text by Stephen Inniss
    Generic term of convenience for animals that do not have a vertebral column. The vast majority of Terragen animals, including such important phyla as the arthropods, annelids, nematodes, echinoderms and molluscs are invertebrate.
  • Jovibiota - Text by M. Alan Kazlev
    Generic term for large aerial xenobiota (sometimes called "gasbags") that have evolved on a number of Jovian Class worlds. Although vaguely similar in form, genetic and biochemical analysis reveals that nearly all evolved independently, hence the Jovibiotic set of morphotypes is an attractor that has appeared a number of times on different worlds.
  • Khowagong  - Text by M. Alan Kazlev
    Large aquatic animals not unlike a Terragen sea slug crossed with a dugong, native to the Pelagic planet Tamarinde (Phoebus Prefecture, Solar Dominion).
  • Leviathan  - Text by Todd Drashner
    Very large sea-going animal native to New Poseidon.
  • Life-zone - Text by M. Alan Kazlev
    The region around a star within which a planet can have a temperature allowing liquid water on the surface. Also known as bio-zone.
  • Ndiangu Mme Anwu System, The  - Text by Radtech497
    Carbon world with a natural ecosystem.
  • Palaeoxenology - Text by M. Alan Kazlev
    The study of ancient or extinct non-Terragen sentient life.
  • Papercutters  - Text by Banelord, Salty, TSSL, Martine, Worldtree, Schwefel Kamm, & DocViviLeandra
    Tiny organisms which cut vegetative matter to feed the symbiotic "molds" they cultivate. Papercutters live in communities of hundreds to thousands of individuals. Since their discovery on the garden world of Macrystis, they and numerous variants have been spread across the Terragen Sphere to millions of worlds and orbitals.
  • Paralymph - Text by M. Alan Kazlev
    Limner blood/lymph circulatory fluid.
  • Phytoplankton  - Text by Stephen Inniss
    Autotrophic planktonic organisms that are the primary producers within their ecology, usually via photosynthesis. Most often they are of microscopic size.
  • Pspyder  - Text by Todd Drashner
    Colony life form native to the planet Trees.
  • Puffer Patch  - Text by Todd Drashner
    A small predator native to Ridgewell, that spends most of its life in a sessile state, but is capable of using metamorphosis to change to a mobile form when environmental conditions require it.
  • PuYlong Ring  - Text by M. Alan Kazlev
    A quasi-living field of planetary ring material.
  • Radial Symmetry  - Text by Stephen Inniss
    Symmetry around a central axis; organisms with radial symmetry have a dorsal and ventral surface but are roughly similar on every side, though they may show fourfold, fivefold, sixfold, or eightfold symmetry.
  • Ran (Epsilon Eridani)  - Text by Updated by The Astronomer 2021
    Inner Sphere system; the birthplace of the Eridanus League, Terragens' first known interstellar polity.
  • Rheolithoids  - Text by Steve Bowers, updated by The Astronomer, dangerous_safety 2021
    High plasticity mineral-based high temperature lifeforms.
  • Rollerox  - Text by Todd Drashner
    Plains dwelling, herbivorous creature indigenous to Nui Spiridonia.
    of their world, using their sonar to navigate.
  • Ruach Singers  - Text by Anders Sandberg
    Tube-like predators from Ruach, able to swim like sea snakes in gas giant atmospheres. They get their name for their extremely powerful sound, which they use for navigation, internal signaling, mating displays and as a sonic weapon. Mirrored Owl hosts.
  • Ruach Toroids  - Text by Anders Sandberg
    Natural inhabitants of Ruach. Symbiotic autotrophs-heterotrophs shaped like translucent toroids, covered with brightly colored photosynthetic symbionts. They filter nutrients through the central hole, which they can also use as a jet to move away from danger and steer. Mirrored Owl hosts.
  • Sailfin  - Text by Todd Drashner
    Aquatic crustacean-like lifeform that is a natural sailboat. Native to the planet Trees.
  • Shona  - Text by Radtech497
    Outer Volumes moon with an unusual indigenous biosphere orbiting a resonant MesoJovian world
  • Shur'rooss'hur  - Text by Steve Bowers
    A domesticated beast on To'ul'h Prime, about the size of a Shetland Pony.
  • Skywhale (To'ul'h species)  - Text by Steve Bowers and Andrew P.
    Large flying invertebrate filter-feeder native to To'ul'h Prime.
  • Skywrack  - Text by Steve Bowers
    Giant plants from the planet Trees up to a kilometre in height.
  • Species  - Text by M. Alan Kazlev
    The basic unit of biological classification in Linnean or neoLinnean systems.
  • Spherical Symmetry  - Text by Stephen Inniss
    Symmetry such that an organism is similar if divided in half along any plane.
  • Spockbat  - Text by Andrew P.
    Flying predator on To'ul'h Prime.
  • Stiltwalker  - Text by M. Alan Kazlev
    Large tetrapodal terrestrial herbivore indigenous to the savannas of the northern continent of Calinder's World (Lacustric Subtype. Cygexpa middle region, near the Zoeific Biopolity border. Eden Institute Scientific Reserve).
  • Terralife - Text by John B (credit to Jonathan Burns)
    Any form of life which developed naturally on Terra (Old Earth). Specifically excludes any mods to the base lifeform.
  • Thiogen Plant Life  - Text by Liam Jones
    In many of the biospheres of the 158 known Thiogen-colonized worlds, Terragen explorers have categorized two main kingdoms of photosynthesising multicellular life: the ribbon plants and the bubble plants, each of which appear to have evolved multicellularity separately. Both kinds have a dark red photosynthetic pigment characteristic of Thiogen biospheres.
  • Tho'rahl'shothan  - Text by James Rogers
    A landsponge native to the planet To'ul'h Prime, commonly used as a recreational drug.
  • To'ul'h Prime Phylogenetic Tree  - Text by Andrew P.
    Evolution of To'ul'h fauna and flora.
  • Tohul Fauna  - Text by Andrew P.
    Complex lifeforms found on Tohul.
  • Trees (Garden World)  - Text by Anders Sandberg
    A self-sufficient Garden World with a spectacular vertical ecosystem; the planet is named after the gigantic trees that grow there.
  • Vijayanta III  - Text by M. Alan Kazlev
    Terraformed by HIE236PPE.
  • Whisper  - Text by Todd Drashner
    Planet covered in a sophont grassland xenoecology, perhaps of artificial origin.
  • Xenobacter Mirabilis - Text by M. Alan Kazlev
    Derived bacterium found on Mykropht III - easily gengineered to form symbiotic upregulated DNA repair systems used by soft radnads.
  • Xenobiochemistry  - Text by Stephen Inniss
    Xenobiochemistry is the study of the comparative biochemistry of Terragen, neogen, and xenobiont organisms. This includes alternatives to water as a solvent, alternative photosynthetic processes (xenophotosynthesis), and many other topics.
  • Xenobiologist  - Text by M. Alan Kazlev
    One who studies non-terragen lifeforms.
  • Xenobiont  - Text by M. Alan Kazlev
    Generic term for alien (non-terragen) lifeform. May be animal-like, plant-like, protistan, exotic chemistry, or any other possibility. Does not have to be sophont. In fact just as on Earth, very few alien species ever evolve any measure of cognitive intelligence.
  • Xenobiota - Text by M. Alan Kazlev
    The totality of non-terragen life on a specific planet or non-terragen ecosystem.
  • Xenophotosynthesis  - Text by Stephen Inniss
    On Old Earth the dominant photosynthetic organisms split water to release oxygen. This is the most common sort of photosynthesis on inner system gardenworlds. However, water is not the only source, and oxygen is not the only possible result.
Related Topics
Development Notes
Text by Stephen Inniss

Initially published on 31 December 2007.

Additional Information