Questions tagged [biology]

For questions about living things. Does not exclude aliens, but additional information is usually necessary (consider using "xenobiology" instead).

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194 votes
18 answers
79k views

How could dragons be explained without magic?

Dragons are a grand classic of fantasy. For this question, let's assume we're talking about the following stereotype: hatches from an ostrich-sized egg and can grow to mountain size if nothing limits ...
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166 votes
26 answers
33k views

Can a substance be more lethal in smaller doses?

Yes, I realize this question is a bit ridiculous, and there are no cases of it in reality (that I can find), but with a bit of truth twisting, could it theoretically be possible? In my fantasy world ...
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139 votes
10 answers
27k views

Everything alive in the world dies this instant. Without bacteria to decompose anything, what happens to the remains? What does this look like?

So when I say everything, I mean everything. Humans, animals, plants, fungi, bacteria, all dead. If the bacteria and other detritovores and decomposers can't decompose anything since they themselves ...
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108 votes
19 answers
16k views

What mechanism can prevent super-healing heroes from accidentally budding?

We’re all familiar with the heroes that can’t die. Honey-badger (with the claws and the angry voice), Dreadpeel, that girl with the weird cheerleading obsession... Basically they all have the same ...
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98 votes
14 answers
10k views

Is there a scientific explanation as to why aliens should look similar to us?

In almost all science-fiction stories that include alien races, said aliens are similar to humans in many ways: bipedal (and often humanoid), communicate with sounds coming out of a mouth, orient in ...
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95 votes
14 answers
25k views

Lembas bread (2000 Calories per bite)

In the lord of rings the elves invented an incredibly nutritious bread/biscuit, as Legolas clearly says only a small bite is just enough to satisfy the needs of an adult man for 1 day. An adult ...
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94 votes
19 answers
46k views

Why would vampires be incapable of entering a non-vampire human’s house uninvited?

I'm looking for a scientific explanation as to why vampires would be incapable of entering a human's house uninvited. There have been many terrific scientific explanations for some of the most ...
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84 votes
19 answers
23k views

Would a 'World Tree' be feasible in real life?

A livescience.com article claims that trees can reach a theoretical height of 400 to 426 feet (122 to 130m). This is due to the tree being unable to carry water up to the top at that certain point due ...
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74 votes
11 answers
9k views

Can a human colony survive on a 'hot' world?

A colony ship headed for its new home countless light-years from Earth suffers an unfortunate malfunction on the final part of its descent phase and crashes onto the planet. Thankfully, the ship ...
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74 votes
4 answers
8k views

Can you simply scale up animals?

There have been a number of questions focusing on mythical creatures where the logical approach to answering has been to scale up an existing animal. For example dragon's wings can be extrapolated ...
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68 votes
19 answers
16k views

How would an astronaut conclude he's on Earth, but 600 million years in the future?

Say we have a group of space travelers who have been frozen inside a sleeper ship for an enormous amount of time that left when Earth was recognizable. When they thaw out and reach their destination, ...
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67 votes
25 answers
15k views

How can waste from the body be removed without being expelled from the anus?

Humans are savage creatures. This is indicative in the way they get rid of bodily waste. Squatting over a glorified hole in the ground or aiming their spear tip toward the same hole and hoping for ...
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65 votes
16 answers
12k views

Is Cancer Biologically Universal?

Cancer works by making cells split and reproduce at an accelerated rate, slowly and painfully killing the afflicted. Its true weapon lies in its ability to surpass the immunity system. As far as I ...
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64 votes
13 answers
18k 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 ...
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  • 3,074
63 votes
15 answers
39k views

Would the human body support living on planets with a greater gravity than Earth?

I once read a novel about a prison-planet which was chosen to make the prisoners suffer. One of the different "tortures" was a gravity three times higher than that on Earth. Would the human body ...
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62 votes
9 answers
7k views

How does the Booze-Rat fuel its defensive mechanism?

Of all the creatures in Hatjörn's dominion, there is none as peculiar as the Murinae Spirita, the mean booze-rat. A vermin so resilient that has developed the most wondrous means of defence and thus ...
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61 votes
8 answers
13k views

Does a grenade kill you the same way a gun does?

Disclaimer This seems a particularly stupid question, but the more I think about it, the less trivial I find it. Worldbuilding possess the most appropriate tags. It does not fit in physics-network ...
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60 votes
10 answers
24k views

A Bird that Never Touches Ground

Birds, as we currently know them, build nests and lay eggs on the ground. People and things with sharp teeth live on the ground. There are also things with claws and beaks up in the air, but fewer. I ...
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59 votes
17 answers
12k views

How do you power all the nanobots?

We have successfully put 37 trillion nanobots the size of a red blood cell into the experimental group test subjects' willing participants' bloodstream, but without a power source, the nanobots clot ...
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  • 1,070
59 votes
12 answers
17k views

Is a man-eating plant realistic?

Carnivorous plants live in nutrient-poor, highly lit habitats, such as bogs or rocks. For example Earth's biggest carnivorous plant, Nepenthes rajah, lives on mountain-tops with high concentration of ...
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58 votes
20 answers
8k views

Why Do My Super-Soldiers Constantly Mutter Their Thoughts Out Loud?

I am creating a race (either near-alien or a human sub-species) in a science fiction setting that have an unfortunate "tell." While they can stay silent in non-social (stealth-requiring) ...
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58 votes
12 answers
8k views

How can an organ that provides biological immortality be unable to regenerate?

After Cain killed his worthless brother Abel, he was unjustly cursed by God to wander the earth forever. On his travels, he met a sympathetic woman named Lilith. They discovered that they had a mutual ...
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57 votes
17 answers
7k views

Would charging unicorns survive the impact with a line of infantry?

The unicorns would be used to charge a line of infantry with their horn. They are as big as a horse and the horn is similar to this image: The infantry is a standard medieval army made mostly of ...
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57 votes
3 answers
18k views

Is there a maximum size an ocean bound creature could grow to?

Assuming the ocean is deep enough and not overcrowded is there any upper limits to the size a "sea monster" can grow? On land creatures are limited by gravity, they have to be able to generate the ...
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56 votes
10 answers
8k views

What could cause sugary rain?

In a world very similar to ours, rain has a high concentration of simple carbohydrates in it, enough to sustain life on the surface. After some rainfall, this sugary rainwater is left behind and some ...
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54 votes
25 answers
8k views

Lifeform - resistant to gunfire but vulnerable to melee

Is there a plausible makeup for a lifeform which is highly resistant to even very advanced firearms (or any ranged weaponry for that matter), but can be injured more readily (albeit still a major feat)...
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53 votes
23 answers
13k views

What possible scientific reasons could there be for a vampire to only be killable via wooden stake to the heart?

This excludes metal stakes, knives etc. to the heart, it's not the bleeding out that's the issue. Just for some reason, a wooden stake to the heart ends a vampire. Why? Assume the type of vampire ...
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53 votes
18 answers
13k views

Is it possible for a species to have more than two sexes?

Every species I'm aware of on earth has two sexes (with the possible exception of species which change their sexes to allow self fertilization). Is it possible for a species to evolve which could ...
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52 votes
19 answers
27k views

What would be the possible benefits of pointed ears?

The title fairly well sums up the question. We all know elves have pointed ears. Whether they be LotR style with slight tapers, or full blown foot long impracticalities, all elves have pointed ears. ...
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52 votes
4 answers
6k views

What would a planet spinning fast enough to allow geostationary orbit near the surface look like?

From an answer to a previous question of mine: A planet spinning fast enough to allow geostationary orbit near the surface would result in odd side effects. Any object at rest on the equator would ...
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51 votes
6 answers
7k views

Could Cobalt bind to nitrogen the same way iron would to oxygen in an alien respiratory system?

I'm making this whole other alien world and I made it an ammonia world, so there is a lot of nitrogen in the atmosphere. Would nitrogen be a good gas to breathe in an ammonia world and would Cobalt be ...
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49 votes
12 answers
5k views

Natural Projectile Weapons

I'm not aware of any animals which have evolved projectile weapons that they fire. There are a number that spit venom but none that even throw rocks, let alone using projectiles. On the other hand ...
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49 votes
5 answers
6k views

Anatomically correct sharknado shark

Raining animals is a rare meteorological phenomenon in which flightless animals fall from the sky. Such occurrences have been reported in many countries throughout history. One hypothesis is that ...
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49 votes
3 answers
9k views

How early was the Earth liveable for today's humans?

Say you were to drop a (bunch of) human(s) at some past era of our Earth. I'm assuming they might encounter a few problems such as the composition of the air not being breathable, the water being too ...
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48 votes
25 answers
9k views

With what liquid should I fill my dead, intraversable seas?

My planet has interesting geography; there are large islands, each with a unique civilisation of people. But separating them are impassible barriers; they consist of a double range of tall, steep ...
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48 votes
29 answers
11k views

Poison which constantly needs to be treated by antidote to not get killed

Inspired by Frank Herbert's Dune: Action Joe is kept prisoner in Doctor Evil's prison. Doctor Evil knows that Joe's escape is inevitable. So he decides to introduce poison to Joe's body. Joe gets his ...
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48 votes
15 answers
13k views

What injury would be of little consequence to a biped but terrible for a quadruped?

Let's imagine a group of people who can turn from human to wolf at will. Wolves are quadrupeds, and humans are biped, so I guess their weight is differently shared in their body, notably when they ...
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48 votes
8 answers
11k views

Is it harder for an intelligent octopus to live on land, or a human to live in space?

I have a race of octopodes with the same intelligence distribution as humans. I want them to “colonise” land to a similar extent as we have “colonised” space; have regular transport between the ocean ...
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48 votes
11 answers
15k views

Given immortality can animals become intelligent?

The animal in question starts off with reptile like intelligence, classic gecko and is a singularity, the only individual of his species to be immortal. It can die and be killed but for the sake of ...
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48 votes
9 answers
10k views

Could an organism have evolved to kill its prey by shouting at it?

I've recently been replaying Skyrim (for about the fifth time now), and I've stumbled across something I thought would make for an interesting question. The Greybeards are a group of extremely ...
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48 votes
11 answers
19k views

How could we time travel backwards without killing everyone with germs from the future?

Consider a world in which time travel has been made viable possibility. Initially, many are ecstatic at the new technology and the knowledge it will unlock. However, biologists and other scientists ...
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  • 598
48 votes
7 answers
34k views

If accelerated natural healing were to occur, what would happen to the human body?

The Details: The human body is capable of impressive acts of self-repair, but such processes take a lot of time, and can take a toll on the body. Infection or other complications can also develop, and ...
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  • 1,628
46 votes
11 answers
8k views

Is it possible for two symbiotic lifeforms to be born from the same egg?

Firstly, I'm not looking for an organism that gives birth to two separate species (like a human that gave birth to a human baby and a puppy) as I'm fairly sure that is impossible (though feel free to ...
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  • 12.4k
46 votes
12 answers
11k views

Is there an evolutionary advantage to having two heads?

This is a classic of fantasy/sci-fi stories. A creature with two heads, two brains, two distinct personalities, sharing a single body. An entire race of Siamese twins. But the question is, what ...
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  • 2,703
46 votes
8 answers
26k views

Can plants survive without animals?

Could a world with no animals whatsoever (not even insects, no humans, etc) still have plant life? These plants do not have to include all the plants in our world, or even any of the same plants. I ...
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  • 3,480
45 votes
22 answers
8k views

Advantage of luminescent eggs?

For example, a quote from one of the Witcher 3: Blood and Wine's side quests says The eggs themselves are a sight to behold, luminescent. The man (hologram) is referring to giant centipede eggs. ...
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45 votes
16 answers
14k views

How could elves survive without any fat cell in their body?

Have you ever seen a fat Elf? I haven't, and I think there's an unexpected reason. You see, Elves aren't really the best workers or at least working the land and cultivating food is not something ...
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45 votes
4 answers
8k views

How many people would have to be killed to make the streets 'run red with blood'?

For example, a street this wide to have enough blood run down the length shown in this photo? Assume that the blood isn't going down storm-drains for whatever reason and assume the stretch of road is ...
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44 votes
15 answers
13k views

Would a horse be sufficient buffer to prevent injury when falling from a great height?

I'm writing a sci-fi story with some fantasy elements, and I'm trying to keep even the most outrageous moments grounded in the laws of our universe. This is one of those moments. The Situation A man ...
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  • 543
44 votes
18 answers
9k views

Why did dragons evolve to be smart?

Before you comment "dragons can't happen", we've been there before. Based on the question linked above, assume dragons are scientifically plausible. You may change what you need about the ...
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