93 votes
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If all natural sources of oxygen production stop, how long do we have?

All the info we need to calculate this is in the wiki for the oxygen cycle. The atmosphere gains and loses about the same amount of oxygen each year: 3 $\times$ 1014 kg. It also currently holds 1.087 $...
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87 votes

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

Broken Phalanges(blue on the middle image)AKA toes and fingers Broken fingers. humans can still use their hands with one or two broken fingers, (better with a splint) but a wolf is not running on ...
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80 votes
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Advantage of luminescent eggs?

The species is parasitic in at least one stage of life. Glowing eggs attract creatures that want to eat the egg (since eggs have lots of fat in them, and don't run away or fight). (Thanks to an ...
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  • 17k
63 votes
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What injury would be of little consequence to a biped but terrible for a quadruped?

Wikipedia says: All dogs (and all living Canidae) have a ligament connecting the spinous process of their first thoracic (or chest) vertebra to the back of the axis bone (second cervical or ...
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  • 5,901
61 votes

Advantage of luminescent eggs?

On Earth poisonous animals are often brightly coloured, e.g. Poison dart frogs. Perhaps bioluminescence evolved as a signal that something is poisonous, and the eggs are poisonous to predators, or ...
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57 votes

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

Both Arms If I incapacitate both your arms, you can still walk and run. If you turn into a wolf then you are limited to pushing your torso across the floor. Still has a consequence for a biped but ...
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  • 1,407
54 votes
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Can a human being live with a continuous stream of blood instead of pulses?

That’s a real thing. The pump console usually comprises several rotating motor-driven pumps that peristaltically "massage" tubing. This action gently propels the blood through the tubing. Or ...
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  • 68.5k
45 votes

How to modify the human eye to see into the ultraviolet and infrared bands?

This a complicated answer because perception is created at multiple points in the optic chain starting with the lens (which is slightly colored and therefore actively filters out UV and purples) to ...
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  • 1,080
42 votes

Fart & Furious: flatulence as acceleration booster possible?

I don't think it is viable. If you want to propel the athlete of mass m to certain velocity v starting from rest, you need to provide a momentum $P = m_a \cdot \delta v_a$. The same momentum has to ...
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  • 238k
37 votes
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How can a dragon take off to the air silently?

Owls & co. already do this, thanks to the particular structure of their feather. Since I imagine your dragons don't have feather, they might have some structure leading to the same result. ...
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  • 238k
34 votes
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Symbiotic benefits for large sentient bio-machine

The neuro-pathways of the suits are very simple when they are "built". There is a large cluster around the neural-link port that handles all the sensory input from the suit to the human and all the ...
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34 votes
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Dragons have a constraint on muscle mass that isn't dedicated to flight. What's the best natural physical weapon for them?

Tail whip. (It won't lower defense tho) The tail can act like a whip, snapping at opponents. If sufficiently long and flexible it could be used to target opponents from lots of different angles. This ...
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  • 3,802
33 votes

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

The answer is "it's possible, but VERY unlikely". There's a lot that goes into this, but the short answer is that there's no guarantee the proteins that developed on this planet will be compatible ...
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  • 11.1k
31 votes

Dragons have a constraint on muscle mass that isn't dedicated to flight. What's the best natural physical weapon for them?

WINGS Since most of the dragon's muscles are wing muscles, it makes sense to use the wings as weapons. The main wing bones must also be very strong to carry it during flight. First, the dragon could ...
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28 votes

Are hydrocarbons viable foods for larger organisms?

Yes, But...: Biologically, it's certainly possible for multicellular organisms (either directly or through the actions of symbiotic bacteria) to utilize petroleum as an energy source. Life makes ...
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  • 52.3k
26 votes
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Biology of a Firestarter

The simplest way for an organism to start a fire is with a pyrophoric chemical. This is a chemical that will ignite spontaneously when exposed to the oxygen in air. All your fire-starter would need to ...
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  • 13.5k
25 votes
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What would be the disadvantages and advantages of having four fingers instead of five?

Speaking from a software guy's perspective. If we (homo sapiens) had evolved without the pinky finger, some tasks would be more difficult, and some would become easier. Any task that has to do with ...
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  • 951
25 votes
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Can humans learn unique robotic hand-eye coordination?

A month to a year The human mind is incredibly flexible. Via association we can learn a great deal. When you start riding a bike or car you can see this very well. Moving your arms and legs in certain ...
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  • 27.3k
25 votes

If Spiders Were the Size of Horses, What Sound Would They Make?

There would be a mechanical clicking or clacking sound as it moves. (I'm extrapolating that it becomes a loud clacking sound based on size.) The largest spider in the world makes a clicking sound as ...
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  • 9,888
25 votes

If Spiders Were the Size of Horses, What Sound Would They Make?

No sound at all The majority of spiders alive today are some form of ambush or trap predators. Making sound kind of spoils the surprise that the spider was planning. For a giant spider that is ...
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  • 1,218
24 votes

Dragons have a constraint on muscle mass that isn't dedicated to flight. What's the best natural physical weapon for them?

Kill Them Like Aeschylus Or: How I Learned To Stop Melee And Love The Bomb You have an intelligent flying animal, with multiple gripping limbs, that is massive enough to carry some not-...
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  • 14.4k
24 votes

Can humans learn unique robotic hand-eye coordination?

Humans routinely learn and master how to control an excavator: a very long arm with the body moving on way more compact base, which is the same situation you are describing. It doesn't take that long ...
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  • 238k
23 votes
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Why are low gravity humans depicted as TALL?

Considering that all those lower-gravity environments have artificial life support, which (presumably) is kept at a nice, even temperature, then if we presuppose that the temperature is slightly ...
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  • 1,250
23 votes

Advantage of luminescent eggs?

Let's assume bio-luminescence is rare and not the norm: if the environment is full of bioluminescent rocks, then it would be more a camouflage. So back to basics: bio-luminescence makes things visible,...
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  • 2,332
23 votes

What is the bio-mechanical plausibility of a fox with venomous fangs?

Solenoglyphy is not the only envenomation mechanism that snakes can use there are also opisthoglyphous and proteroglyphous snakes, I would suggest that either of these mechanisms would be more ...
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  • 44.3k
22 votes

How can dragons propel their breath attacks to a long distance

They just need for the liquid to have a very high surface tension or even be slightly gelatinous (like napalm, which was developed for the same needs you have). Then they can employ a relatively ...
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  • 52k
22 votes

Can humans learn unique robotic hand-eye coordination?

Here's a clip of a monkey feeding itself with a simple robotic arm controlled via a direct brain interface, taken in the implausible scifi future of 2008: (Nature article on the subject) This work ...
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22 votes

If Spiders Were the Size of Horses, What Sound Would They Make?

Whatever you want One of the limiting factors on the size of spiders and other arachnids is their relatively simple, primitive respiratory system. However, increasing the atmospheric percentage of ...
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  • 18.9k
20 votes

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

Most plant food on Earth won't sustain people. That's why people were hunters before farmers. Meat, at least earth-meat, is easy to digest in almost every form. Few plants have anything edible about ...
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  • 201
20 votes
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Lizardfolk and the problem of balance and anatomically sound tails

First I need to mention that bipedal is different than upright. A t-rex is bipedal, it is not upright. So you may want to clarify what you want. The tail should actually help balance not hinder it, ...
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