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Questions tagged [xenobiology]

For questions related to the biology of extra-terrestrial organisms. This tag implies the use of the science-fiction tag. Use the science-based or hard-science tags to impose greater scientific restrictions (see warning in tag wiki). The goal of this tag is to answer the question using known science.

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Would humans be able to derive nutrition from foodstuffs found on alien planets?

Suppose humans have developed the technology to travel between star systems. This might be some science-fiction method like warp drive, jump drive, peanut butter drive, hyperspace drive or whatever, ...
user's user avatar
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40 votes
6 answers
3k views

How to evolve biological radios?

Radio Thinkers Creatures that communicate by biological radio pops up in science fiction occasionally and it's a fun idea. However, there are some practical concerns with regards to evolving a radio ...
Green's user avatar
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28 votes
6 answers
10k views

Maximum size of an exoskeletal creature

On a world I am building, I have a species of creatures that evolved from crustaceans. The problem is that while they have an exoskeleton, they also live on a world with the same gravity as Earth. I ...
TrEs-2b's user avatar
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66 votes
13 answers
19k views

What kind of natural armor would stop bullets?

It should not resist 50 cal bullets, but an armor which could protect a creature from the US standard issue rifle, for example. Here are a couple of things the armor needs to do: Protect the creature ...
OneSurvivor's user avatar
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31 votes
2 answers
1k views

Hydrogenenic Photosynthesis: Strategies for animals

Hydrogenic photosynthesis reduces methane and water to build biomass ($\text{CH}_2\text{O}$) and releases hydrogen: $$\text{CH}_4 + \text{H}_2\text{O} + \text{photons} \to \text{CH}_2\text{O} + 2\...
rumguff's user avatar
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44 votes
14 answers
12k views

Anatomically correct Arachne

In the fantasy culture it's not uncommon to find Giant spiders with the upper body of a human. There are many variants as the spider body having only 4 legs and the upper human body have 2 additional ...
Charon's user avatar
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29 votes
6 answers
4k views

Plausible biological alternative for normal photosynthesis

People have been trying to imagine elaborate alien biologically possible ecosystems for a while. A lot of people seem to both want but ignore one of those fundamental aspects of our own ecosystem, ...
anon's user avatar
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28 votes
5 answers
25k views

Humanoids with digitigrade legs?

I've designed an alien race of bipedal humanoids with digitigrade legs. This race's advanced scientific progress means that they use traditionally human-associated technology, or similar (such as ...
XenoDwarf's user avatar
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18 votes
5 answers
2k views

How might kinetosynthesizing "plants" look?

Suppose that there is a moon, orbiting a gas giant, and that gas giant is a rogue planet - it moves freely through the universe, unbound by the gravity of a star. This means that one, the moon will ...
SealBoi's user avatar
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23 votes
5 answers
5k views

What else is involved in "silicon based" life?

Silicon is often brought up in science fiction as being very similar to carbon, just below it on the periodic table. The silicon-based "organic" molecules are more tightly bound and thus would find a ...
JDługosz's user avatar
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13 votes
6 answers
3k views

How CAN we scale up living creatures to be giant sized?

Piggybacking on this question: Can you simply scale up animals? how CAN we scale up living creatures to be giant sized? What would need to done to make truly giant animals (Dragons, Kong, Godzilla, ...
Len's user avatar
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8 votes
11 answers
3k views

Why might a plant evolve a brain and the ability to move?

I was thinking of a situation in which an Extra Terrestrial plant life form evolves a nervous system and eventually a brain. This plant diversifies into a variety of different life forms with some ...
Anders Gustafson's user avatar
32 votes
10 answers
8k views

Is it a forgone conclusion that any exo-bacteria discovered on an alien, albeit Earth-like planet will be deadly to human life?

Would the discovery of alien bacteria found on even an Earth analog planet preclude the possibility of colonization due to the potentially deadly nature of bacterial/viral infections? Put differently, ...
Brian's user avatar
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16 votes
7 answers
2k views

Which conditions would make aerial filter feeding successful?

Premise On Earth the seas have numerous filter feeding species, large and small, sustaining themselves on the microscopic nutrients and organisms that drift in the current. The largest animal ...
rek's user avatar
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16 votes
3 answers
848 views

Heterochiral biosphere: a two-handed world

Original post: Imagine a world in which both left- and right-handed chirality appeared and evolved into a variety of complex organisms comparable to post-Cambrian Explosion Earth (both plant and ...
rek's user avatar
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11 votes
3 answers
4k views

Vertebrate-like creatures with more than four limbs

On Earth, land vertebrates generally have four limbs. Other creatures such as insects can have more limbs, but those creatures tend to be small. I'm thinking of creating an alien ecosystem with ...
Inflationary_Bubble's user avatar
8 votes
3 answers
4k views

Alternate Elemental Bases for Life

Here on Earth, Carbon is the base of all life from plants to fungi to animals. The most common alternative that exists is Silicon, but surely out of the over 100 elements other than Carbon and Silicon,...
TrEs-2b's user avatar
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22 votes
14 answers
3k views

Would an alien lifeform be able to achieve space travel if lacking in vision?

Think of this alien life form as something resembling earth bats, placed in a planet with Earth-like conditions. Micro-bats have small and poorly developed eyes. Similarly, this alien species is ...
Liam00's user avatar
  • 267
19 votes
4 answers
3k views

How to make my Beast-Of-Burden work?

Disclaimer: This question is the first of a new series of questions of mine about introducing hexapedae to the fauna of my conworld. There are/will be other questions addressing i.a.: ecosystems, ...
dot_Sp0T's user avatar
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19 votes
7 answers
4k views

Alternatives to DNA

I am in the process of creating my universe, and have based it on semi-hard science. The universe that I have created is quite extensive, and I thought that it would be unreasonable for the only kind ...
user avatar
19 votes
6 answers
2k views

Anatomically correct Ent

The tree small giant creatures resembling people usually with beards are present in many fantasy stories, but that's it... it is fantasy. From a scientific viewpoint how would such creature even exist ...
Charon's user avatar
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17 votes
12 answers
4k views

Are "none-of-the-above" species classifications possible?

Let's not delve into specific genuses, families, orders etc. Broaden your definition of "classifications" to words like "mammal" or "fish", "crustacean" or "avian". Science fiction depictions of ...
Zxyrra's user avatar
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17 votes
6 answers
2k views

Could complex, macroscopic life arise and exist without cells?

For the purposes of this question only, I am making the following definitions: Cell: a microscopic, membrane-bound subunit of a living organism. Living organism: an entity composed primarily of ...
ApproachingDarknessFish's user avatar
12 votes
5 answers
920 views

How could a biological loudspeaker work and naturally evolve?

In this Answer I suggested that an animal could have a tampani acting as a loudspeaker, as in Vernor Vinge’s The Blabber, later featured as the race called Tines in A Fire Upon the Deep. In the ...
JDługosz's user avatar
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8 votes
3 answers
771 views

Gas-based circulatory system?

I'm making a species which has a gas-based circulatory system. How would one go about designing such a system, in which liquid blood is replaced by some kind of gas? What kind of blood vessels would ...
ArborianSerpent's user avatar
8 votes
3 answers
680 views

What sea-dweller did my hexaped Beast-of-Burdern evolve from?

Disclaimer: This question is the third of a new series of questions of mine about introducing hexapeds to the fauna of my conworld. There are/will be other questions addressing i.a.: characteristics, ...
dot_Sp0T's user avatar
  • 12.1k
16 votes
6 answers
3k views

Plant based lifeforms: brain equivalent?

In lots of science fiction works that visit other planets we are often introduced to intelligent plant based lifeforms, be they humanoid looking or potted plant looking. I'm curious as to what part ...
EveryBitHelps's user avatar
16 votes
17 answers
5k views

Can a reproductive system that allows interspecies breeding be made believable?

I have in mind this alien species that can reproduce with humans. The result will always be of the same species as the alien; the human is used only to vary the genetics so the newborn won't be a ...
Hatoru Hansou's user avatar
15 votes
3 answers
3k views

What kind of planet could have giant sand worms?

I would like to have giant sand worms similar to the ones in the 'Dune' novel. What should the planet be like so that they are realistic? Giant sand worms are roughly 100m long and 5 meters in ...
quarague's user avatar
  • 1,651
12 votes
4 answers
7k views

How could mermaids talk with gills?

Recently I was pondering mermaids and was wondering how their respiratory systems work. Most importantly, how could their vocal chords continue to function? Secondly, how would they draw the water ...
Emily Campbell's user avatar
11 votes
7 answers
2k views

Is it possible for a creature to exist as a biological nuclear reactor?

This is somewhat different to this question on the possibility of biological fusion reactors as I am curious if a living FISSION reactor is more plausible.
Jacob Blaustein's user avatar
10 votes
5 answers
506 views

Alternative biological oxidizer

A concept I've encountered a few times is aliens with "vastly" different biology than terrestrial creatures. In this case, I'm interested in replacing the parts that use oxygen with something a bit ...
Andon's user avatar
  • 11.6k
10 votes
1 answer
2k views

Ultraviolet bioluminescence

Bioluminescence is badass. It involves living beings emitting bright light in the visible spectrum. Would it be, though, possible that a lifeform emits UV (ultraviolet) light? Does it occur in ...
Z..'s user avatar
  • 5,356
7 votes
1 answer
759 views

Can we scale down humans to the size of a mouse?

Can we make a human brain and body the size of a mouse’s while still retaining the same level, if not more intelligence? Like how tech has evolved to be smaller but more efficient or how cars are ...
Razorlazer's user avatar
6 votes
3 answers
644 views

No Iron for your fair-folk maiden? (Part 1: alkaline)

Excuse the broad question but I couldn’t resist making a metal pun. So in my universe the Fair Folk encompass a large group of creatures. They live in their own little pocket universe, in which ...
Nick's user avatar
  • 5,293
4 votes
2 answers
595 views

Biological explanation of age stopping in near-human aliens

There's a species called Foos. Foos are fairly similar to humans. In a primitive society, in fact, they would appear identical to humans in actual physical appearance, mannerisms, and base behavior. ...
Ranger's user avatar
  • 17.5k
0 votes
1 answer
128 views

How to support the evolution of a giant creature across generations [closed]

In my story, in which I want to rely on scientific logic as much as possible, I want a creature to evolve to become at least the size of a country and you can live in space. The means of evolution for ...
The villager's user avatar
148 votes
12 answers
18k views

How do Glass Ants create their tunnels?

***** Xenobiology expedition 'Profundity': Log entry 504 ***** Glass Ants are a fascinating species. We discovered them on an arid desert world last visited by humanity aeons ago. They seem to have ...
Joe Bloggs's user avatar
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35 votes
7 answers
6k views

What would an efficient swimming creature in magma be like?

This question is specifically about the mechanics of an alien creature swimming in highly viscous magma, the unlikeliness of life surviving at magma temperatures etc isn't relevant. Just imagine it's ...
Fred the John's user avatar
20 votes
4 answers
1k views

Physiological adaptation of life on a planet orbiting a red giant.

Let's say there exists an Earth-like exoplanet which orbits a normal star, with a similar process regarding the evolution of life on earth, yet the star became a red giant during said evolution. ...
Lutro's user avatar
  • 1,018
18 votes
4 answers
2k views

Are 'ambiskeletons' viable?

A recurring problem in trying to create large creatures is the square-cube law as it applies to upscaling familiar animals, particularly those with exoskeletons: if you double an animal's size, its ...
rek's user avatar
  • 13.1k
15 votes
2 answers
1k views

How far could a planet be from its star and still be kept habitable by intense greenhouse gases?

Epimetheus is a planet with about three times the mass of Earth orbiting a sun-like star in the Andromeda galaxy. However, two major factors separate Epimetheus from Earth. First, it has a thick ...
ckersch's user avatar
  • 46.4k
15 votes
6 answers
3k views

Xenotaxonomy: the Science of Categorizing Extraterrestrial Life

On Earth, we use taxonomy to organize biological organisms into an identifiable hierarchy in which organisms that are evolutionarily related are placed in close proximity. This evolutionary approach ...
Frostfyre's user avatar
  • 25.2k
14 votes
2 answers
639 views

How big can Europan fish get?

Assumptions: Jupiter's moon Europa has a salty subsurface ocean in contact with a rocky mantle. The ocean is populated by hydrothermal vents produced by tidal heating. Global heat flow is similar to ...
Zxyrra's user avatar
  • 20.6k
14 votes
3 answers
544 views

Are there physiological traits common to all tool-building species?

Alien and fantasy creatures can be designed in an infinite number of ways. But are there physiological traits that would be common among all tool-developing (technology-building) species? As an ...
JBH's user avatar
  • 127k
12 votes
4 answers
2k views

Why would a land creature have tentacle-like appendages

Why would a creature that lives on the surface of a planet evolve limbs that can bend at many points (like a tentacle or elephant trunk) and still end in some sort of hand-like appendage?
TrEs-2b's user avatar
  • 56.2k
12 votes
5 answers
4k views

Alternative elements for oxygen transport in an alien blood

I am designing an alien civilization for a story, and I am currently in the biological part. They will be oxygen breathers, so they will need to have that oxygen delivered inside their bodies, and I ...
Carlos Zamora's user avatar
11 votes
3 answers
656 views

What would be the human physiological reaction to an alien biosphere?

This is the first question about colonizing an alien world; the second question on agriculture on this planet is here. So here's the idea: human beings travel to and land on an Earth-like world with ...
Kryten's user avatar
  • 371
10 votes
2 answers
1k views

How could non-photosynthetic non-chemotrophic autotrophs create usable energy?

On Earth, the vast majority of the biosphere is ultimately dependent on a large number of autotrophic organisms that produce usable energy in the form of glucose by using photosynthesis. However, on ...
ckersch's user avatar
  • 46.4k
10 votes
1 answer
497 views

Where would my hexaped Beast-of-Burden fit into Linnaean taxonomy?

Disclaimer: This question is the second of a new series of questions of mine about introducing hexapeds to the fauna of my conworld. There are/will be other questions addressing i.a.: characteristics, ...
dot_Sp0T's user avatar
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