The fantasy Pseudo-science question and answer thread.

[Draconi Redfir]

Because every so often you have a question regarding a creature that is impossible to exist, but still want to know some scientifically plausible feature of it to have it at least make a smidgen of sense.

Basically, this is an attempt at a thread where people can come in asking for advice on their fictional creations on how to make them at least somewhat realistic or make more sense.

that and i don't want to bog down the forum with a new thread for every individual trait of this fantasy species I'm making.


for example, the current question on my mind:

Assume for a moment that there is an 8ft tall humanoid creature that is a distant descendant of a Starfish. This creature evolved to live in Desert and desert-mountain regions. It was never Arborial (living in trees), and somehow supports itself on a system of densely-packed muscle tissue, having no bones to speak of. the best it has is some Keratin forming it's teeth and possible nails.

What do you think it's hands and feet would look like?

currently have them as being human-like, but right now I'm thinking that doesn't make a lot of sense. Since they're descended from Starfish, they might have some degree of five-way symmetry, so hands could maybe be three fingers with two thumbs, one on either side of the palm? The feet are a bigger question. Since they have no bones and were never arboreal, human-feet don't make much sense. Maybe something like an elephant-foot? or their three-finger two-thumbed hands but flatter? What do you guys think?

obviously it doesn't need to be perfectly scientifically accurate, just somewhat believable.

edit: Forget it. i'm not getting the kind of information i'm looking for with this particular question. feel free to use this thread for other questions though. someone was asking about the Graboids from Tremors, why not help with that?

[Tvtyrant]

Because every so often you have a question regarding a creature that is impossible to exist, but still want to know some scientifically plausible feature of it to have it at least make a smidgen of sense.

Basically, this is an attempt at a thread where people can come in asking for advice on their fictional creations on how to make them at least somewhat realistic or make more sense.

that and i don't want to bog down the forum with a new thread for every individual trait of this fantasy species I'm making.


for example, the current question on my mind:

Assume for a moment that there is an 8ft tall humanoid creature that is a distant descendant of a Starfish. This creature evolved to live in Desert and desert-mountain regions. It was never Arborial (living in trees), and somehow supports itself on a system of densely-packed muscle tissue, having no bones to speak of. the best it has is some Keratin forming it's teeth and possible nails.

What do you think it's hands and feet would look like?

currently have them as being human-like, but right now I'm thinking that doesn't make a lot of sense. Since they're descended from Starfish, they might have some degree of five-way symmetry, so hands could maybe be three fingers with two thumbs, one on either side of the palm? The feet are a bigger question. Since they have no bones and were never arboreal, human-feet don't make much sense. Maybe something like an elephant-foot? or their three-finger two-thumbed hands but flatter? What do you guys think?

obviously it doesn't need to be perfectly scientifically accurate, just somewhat believable.

Pentagonal symmetry suggests that it is going to branch off into packs of 5, and then either resplit or recombine. So the body is going to be a "head" with 5 arms that morphed together like a sea cucumber along its body, then rebranched into limbs later. I would suggest 5 arms that approximate a tail, two legs, and two arms. Then there are five fingers on each arm that are tentacle like, the feet had tentacles that combined together like an elephant's toes around a ball, and the tail is 5 frond like tails sprouting from a short stump of an arm. Think very long fingers.

[Draconi Redfir]

i was more thinking the "Body" is the torso, and the "Head" is the 5th limb, now used as a communication and sensory extremity. So kind of like Patrick Star from spongebob.

[Tvtyrant]

i was more thinking the "Body" is the torso, and the "Head" is the 5th limb, now used as a communication and sensory extremity. So kind of like Patrick Star from spongebob.

That's not really how echinoderm nervous systems work, the "head" is the middle of the body. If you look at the evolution of a sea cucumber it's pretty trippy.

It's also fiction so you can do it however you want, but I don't think that really incorporates any of the Echinoderm traits.

[Draconi Redfir]

yeah, well the head and body locations aren't really what i'm looking for here though soooo.... yeaa.

i'm just trying to figure out what the hands and feet would look like.

[Tvtyrant]

yeah, well the head and body locations aren't really what i'm looking for here though soooo.... yeaa.

i'm just trying to figure out what the hands and feet would look like.

"Then there are five fingers on each arm that are tentacle like, the feet had tentacles that combined together like an elephant's toes around a ball,..."

Frond like is the approach I would go with for fingers, and sucked in like a seacucumber for a feet. So the feet would have suckers along the bottom and running up a bit and then the fingers would be long and curly.

[Jay R]

Always do google searches. I found this by searching on "starfish multiple limbs":

Evidently, the underside of starfish limbs have multiple hydraulic tube feet with suction cups.

[Draconi Redfir]

yeah i knew about those, i had them transition to becoming the "Hair" of the creatures, since i knew i didn't want them to be bald. this creature walks on what is the stiff part of the leg of a starfish, modified after a long time to be more flexible in certain areas.

wondering if the elephant-foot idea won't be super viable for them. every biped animal i can think of (humans, birds, dinosaurs, etc) all have the same basic shape, long forward-facing toes, little to no structure on the rear. Round and flat StrongSad-style feet probably won't cut it. Might go something closer to the human foot, but with two big toes, one on either side. Will probably want to still be pretty wide, Camels are probably the largest desert-dwelling animal i can think of, and they have pretty wide feet, presumably so they don't sink into the sand.

So we might be looking at something that kind of combines the Camel's foot with a human's or an ostriches. built for upright movement with forward-facing toes, but still wide enough to prevent sinking into sand.

[Gnoman]

Somethign like those all-terrain canes you can buy nowadays might be reasonable, with a lot of those tiny tentacles on the bottom.

[gomipile]

So, here's something I've been wondering about for a long time. How much peak power in watts or horsepower or whatever would the graboids in the first Tremors film have to exert to move through dirt like they do in the film? And how does that compare to the power output of other similar size animals? Or power output per mass or volume or length^3 or cross sectional area or whatever other measure of other animals?

[Eldan]

That seems like a case where the better comparison is probably digging machinery. Id compare them to the power output of a particularly fast drill, not any kind of animal.

[gomipile]

That seems like a case where the better comparison is probably digging machinery. Id compare them to the power output of a particularly fast drill, not any kind of animal.

My point in comparing to animals is that I hypothesize that their power output would be ridiculously higher than any comparably sized animal. I just want to figure out how ridiculous the difference is.

[Draconi Redfir]

probably pretty ridiculous. i can't remember exactly, but i recall their movement as being the result of sevral spikes along their body moving in and out in a wave patern, with maybe something causing vibrations to loosen up the soil in front of them. definitely doesn't seem like the kind of thing that would be super feasible, unless the characters were wrong about how the creatures moved.

in the first movie, one of the creatures dies by smacking into a concreate wall at top-speed right? you might be able to look up the impact strength of concreate, and use that to figure out how fast something would have to be moving in order to create the cracks that creature created.

in this video at around 1:50 , you can see the two main characters run past a barbed wire fence, followed by the creature in the same shot. you might be able to find how fast the creature is going by guestimating the human's heights(or just look up the actors and how tall they are) , running speeds, the average distance between any two poles of a barbed wire fence like that, and the time between the humans passing one pole and the creature passing that same pole.

that same video also shows you the impact wreckage the creature makes against the concreate wall.

[Eldan]

My point in comparing to animals is that I hypothesize that their power output would be ridiculously higher than any comparably sized animal. I just want to figure out how ridiculous the difference is.

Hmm. I think the best estimate of an animal's power output would be how many calories they need to consume. Estimates online say up to 4000 calories a day for hard labor. One gallon of gasoline is roughly 30'000 calories.I can't really find amounts of gasoline/distance dug for drilling equipment, though. But if they need even just one gallon per day, that's already ten times as much as a human.

[Babale]

Hmm. I think the best estimate of an animal's power output would be how many calories they need to consume. Estimates online say up to 4000 calories a day for hard labor. One gallon of gasoline is roughly 30'000 calories.I can't really find amounts of gasoline/distance dug for drilling equipment, though. But if they need even just one gallon per day, that's already ten times as much as a human.

It's even worse than that, because you have to consider how efficient an engine is in translating chemical energy bound in gasoline into rotational energy of the drill, and how much of that energy translates into kinetic energy moving soil backwards and the creature or machine forwards. Then you have to compare that to how much of the calories a creature eats are actually converted into usable kinetic energy for limb movement. Even though our digestive system is probably better at extracting energy from food than an engine is at extracting energy from gasoline, the body has a bunch of other stuff it needs energy for (respiration, cell division for growth or repair, maintaining homeostasis); so much less of the energy stored in food is converted into forwards movement, compared to the energy generated in a drilling machine's engines.

[Babale]

The efficiency question is an interesting one. Could I, in a full day's hard labor, move more dirt than a drilling machine can with two cups of gasoline?

The classic showdown between John Henry and the drilling machine should have limited them to equal calories in fuel.

I think the machine is definitely going to be way more efficient. It's not wasting energy on running a complex brain -- it's just drilling. It isn't repairing damage as it goes, but your body is. It isn't preparing to duplicate itself, but your body is. It cools itself with an efficient fan that blows air past the engine, or using a radiator; you cool yourself by far more complex metabolic processes (and this makes sense -- the engine can easily operate at a range of temperatures that would kill your body, much less your internal organs. Your body only has a few degrees it is functional within, too hot or too cold and you die).

[jayem]

What do you think it's hands and feet would look like?
currently have them as being human-like, but right now I'm thinking that doesn't make a lot of sense. Since they're descended from Starfish, they might have some degree of five-way symmetry, so hands could maybe be three fingers with two thumbs, one on either side of the palm? The feet are a bigger question. Since they have no bones and were never arboreal, human-feet don't make much sense. Maybe something like an elephant-foot? or their three-finger two-thumbed hands but flatter? What do you guys think?
obviously it doesn't need to be perfectly scientifically accurate, just somewhat believable.

No idea about the believability but rather than being flat palm like, possibly a bit like an octopus/squids tentacles with the 5 equal tentacle 'fingers', equally spaced around round the end of the wrist.
Suckers seem fitting.

[Draconi Redfir]

i really don't think i'm going for suckers or suction cups or tiny tentacles in any capacity. the idea is the starfish developed rapid twitching of their legs to scare off birds, and this developed into locomotion. so all those sucker tentacles became hair instead.

maybe something kind of like those "Blade runner" prosthetic legs since it evolved from a straight limb. but have a small growth on the rear so it actually has a heel. After that... would five-way symmetry even carry over into a single starfish's limb? might just be like, two toes or something come to think of it. enough to give the various microshifts of balance our own toes do, but not being a full set of five.

might maintain the five-fingers five-toes things just to make them a BIT More relatable to humans. and to make sure they don't have that weird thing of having five fingers but two toes or something.

[Babale]

i really don't think i'm going for suckers or suction cups or tiny tentacles in any capacity. the idea is the starfish developed rapid twitching of their legs to scare off birds, and this developed into locomotion. so all those sucker tentacles became hair instead.

maybe something kind of like those "Blade runner" prosthetic legs since it evolved from a straight limb. but have a small growth on the rear so it actually has a heel. After that... would five-way symmetry even carry over into a single starfish's limb? might just be like, two toes or something come to think of it. enough to give the various microshifts of balance our own toes do, but not being a full set of five.

might maintain the five-fingers five-toes things just to make them a BIT More relatable to humans. and to make sure they don't have that weird thing of having five fingers but two toes or something.

What you've got in your head is a vaguely starfish inspired creature that's bipedal, with bilateral symmetry. That's totally fine, mind you; you're creating a fantasy universe, if you want humanoid starfish, great! But if you are asking, what sort of creature could such a starfish evolve into?

In nature we see that evolution never changes two things when it can just change one. Remember, this symmetry doesn't happen just because it looks good -- it has to do with the way that cells divide and arrange themselves at the most basic level. Trying for a form of symmetry more complex than bilateral or radial -- or trying to evolve a relatively complex organism from one form to another - would be incredibly complex and thus unlikely to happen.

So if you like the concept, fantastic, throw these starfish people into your world, my friend. But we cannot really tell you much about scientific plausibility there.

[RagingBluMunky]

My vote for starfish hands is basically, slap a starfish on the end of each limb.
Or, to put it more 'scientifically', pentagonal symmetry. The main body radiates evenly into 5 limbs (2 arms, 2 legs, head), each limb then radiates into 5 digits. The head could have either, each digit dedicated to a sense (or 2 visual, 2 audio, 1 scent), or have the senses evenly spread out over the whole 'head'

[Babale]

You could also go the sea cucumber route for symmetry: take a base starfish. One body surrounded by 5 limbs with the mouth on the bottom.

Over time the starfish becomes more mobile and ambulatory. The limbs extend and begin to carry the body above the ground, allowing for for quicker movement. Sensory organs evolve near the mouth opening and the mouth + sensors are no longer on a flat body; instead the body becomes more tube-shaped. The creature flips over, carrying its mouth and sensory organs at the end of a thick stalk or tube-like torso that rises from the top of the starfish. From its base descend five thick legs.

So what you've eventually got is a creature with a thick, round body. From the top of the body rises a stalk or torso, up to you how thick, but flexible; atop it is the head - a mouth at the end of the stalk (not at its front, like how our mouth is on the front of our head -- at the top instead, but the stalk could be flexible enough to bend forwards so the mouth is facing ahead). Arranged around the mouth are eyes, ears, nostrils, etc -- probably five or ten eyes arranged around the mouth? The exact count is flexible in radial symmetry, but going from radial to bilateral is tougher. So you could go from 5 to 7 or 9 limbs, and if you go with more limbs you can specialize them. So for example, you could have four thicker limbs at the base of the creature, acting as legs, and three thinner, more flexible limbs that act as arms?

[Draconi Redfir]

You could also go the sea cucumber route for symmetry: take a base starfish. One body surrounded by 5 limbs with the mouth on the bottom.

Over time the starfish becomes more mobile and ambulatory. The limbs extend and begin to carry the body above the ground, allowing for for quicker movement. Sensory organs evolve near the mouth opening and the mouth + sensors are no longer on a flat body; instead the body becomes more tube-shaped. The creature flips over, carrying its mouth and sensory organs at the end of a thick stalk or tube-like torso that rises from the top of the starfish. From its base descend five thick legs.

So what you've eventually got is a creature with a thick, round body. From the top of the body rises a stalk or torso, up to you how thick, but flexible; atop it is the head - a mouth at the end of the stalk (not at its front, like how our mouth is on the front of our head -- at the top instead, but the stalk could be flexible enough to bend forwards so the mouth is facing ahead). Arranged around the mouth are eyes, ears, nostrils, etc -- probably five or ten eyes arranged around the mouth? The exact count is flexible in radial symmetry, but going from radial to bilateral is tougher. So you could go from 5 to 7 or 9 limbs, and if you go with more limbs you can specialize them. So for example, you could have four thicker limbs at the base of the creature, acting as legs, and three thinner, more flexible limbs that act as arms?

This doesn't really fit the definition of "Humanoid" though. i already know what the end product is. it's 8ft tall, one head with all the sensory organs, two arms, two legs, and a big torso. it lives primarily in the desert, desert-mountains, and caves it dug out inside desert mountains.

i am literally just looking for ideas on what it's hands and feet could possibly look like to suit it's biology and environment. everything else is off the table.

maybe just switch the discussion to that graboid one, or some other pseudoscience thing. i don't think this discussion is going anywhere.

[Babale]

This doesn't really fit the definition of "Humanoid" though. i already know what the end product is. it's 8ft tall, one head with all the sensory organs, two arms, two legs, and a big torso. it lives primarily in the desert, desert-mountains, and caves it dug out inside desert mountains.

i am literally just looking for ideas on what it's hands and feet could possibly look like to suit it's biology and environment. everything else is off the table.

maybe just switch the discussion to that graboid one, or some other pseudoscience thing. i don't think this discussion is going anywhere.

If you mean more from a "what fits the concept" perspective than a "what could a vaguely humanoid starfish descendant based on our understanding of evolution", then I find that question less interesting, but... maybe the arm is covered in a row of tiny 'fingers' that can wrap around objects and manipulate them? So the limbs taper off rather than having a true hand, but along the last foot or so of the limb are these little fingers, and between the limb wrapping around an object and the little fingers grabbing on, you get the ability to manipulate stuff.