Post-human species

[Simon_Jester]

Not sure I follow your full meaning, Xillian.

But yeah. It's nice to try and have scientific explanations for your spiffy zap guns and superhuman warriors and such. But you can't expect to get whatever you want out of a half-assed explanation, and sometimes trying to explain just makes it sound dumber.

You could maybe have a winged near-humanoid, but the "humanoid" parts of their body would have to be ludicrously pared down and optimized for flight- very light bones, not much muscle mass except on the flight muscles. Body fat would just not be an option, and their dietary requirements would be immense. Even then you might need to use something exotic for the bone and muscle structure to get the necessary strength out of an acceptably light package, and you'd want to reshape a lot of the joints pretty drastically.

They wouldn't look human to us, and biologically they wouldn't be, not really.

[Terralthra]

The canard that bird skeletons are light is simply untrue. The skeletons of similarly-sized mammals and birds are extremely similar in weight. Bird bones are hollow, true; but, the bone mass is denser in birds. (source)

It is incorrect to say that bird skeletons are "light." Their structures are specialized for flight, including hollow centers, but they aren't any lighter than mammal skeletons per body mass.

[Simon_Jester]

I sit corrected.

On the other hand, bird skeletons are not humanoid; they're much better optimized for flight than the skeleton of a winged humanoid of the "angel" type. If we took a bird and tack on a bunch of unnecessary arm and leg (to convert a four-limbed bird with wings stubby little legs into a six-limbed creature with long arms, long legs, and wings)... we're adding weight. To compensate, we either have to bulk up the flight muscles, which are already huge in birds, or we have to lighten the skeleton.

The lightening will probably be in the arms and, to a lesser extent, the legs- the legs still have to be able to support the body weight.

Or am I missing something?

[Commander Xillian]

I have to agree with Simon on this one, the "Humanoid" would more or less only go as far as poseable thumbs and two legs.

Also, would the possibility of both much lighter internal bones, AND an exoskeleton aid in the stress of flight? I'm not knowledgeable on that subject, just rudimentary biology. Sadly, my strongsuit is in Sociology and Psychology so I am more or less useless on that XD

[Simon_Jester]

Also, would the possibility of both much lighter internal bones, AND an exoskeleton aid in the stress of flight?

An exoskeleton would probably be bad; exoskeletons aren't designed to flex very well, and the skin of a large flier will tend to flex. For that matter, exoskeletons in general don't scale well, which is a big reason there's an upper bound on insect size and why you don't see crabs that are fifty feet long.

I could be missing something here.

[Commander Xillian]

No no, I think you got it rather well. I had missed the flexing part, the Exoskeletons would indeed impeed flight. However, if there is a higher oxygen concentration, then it is known that Arachnids, Arthropods and the whole slew of "Bugs" would infact grow enormously. Arthropods breath through pours in their skeleton, so as they get bigger they would need to saturate themselves in a higher and higher oxygen-carbon-dioxide ratio. It's the exact opposite of lungs. A reason spiders/Scorpions/Crabs (I am unsure on Crabs) can get so big, is due to the adaptation of the Booklung.

[Terralthra]

I sit corrected.

On the other hand, bird skeletons are not humanoid; they're much better optimized for flight than the skeleton of a winged humanoid of the "angel" type. If we took a bird and tack on a bunch of unnecessary arm and leg (to convert a four-limbed bird with wings stubby little legs into a six-limbed creature with long arms, long legs, and wings)... we're adding weight. To compensate, we either have to bulk up the flight muscles, which are already huge in birds, or we have to lighten the skeleton.

The lightening will probably be in the arms and, to a lesser extent, the legs- the legs still have to be able to support the body weight.

Or am I missing something?

A six-limbed "angel"-form flying humanoid is impossible. The main flying muscle in birds is the pectoralis muscle, and it's hypertrophied compared to humans: up to 15% of a flying bird's body mass is taken up by the pecs. The wings are literally pulled downward and in across the chest by nearly a quarter of the bird's mass in dense fast-twitch muscle.

In humanoids, the pectoralis muscles work with the trapezius to do almost any movement involving the arms.

Surely you can see the problem in superimposing these two muscular structures. Either the arms would be square in the middle of the massive wing-powering pectoralis, and vestigial at best, given that their main positioning muscles are devoted to wing-strokes, or the wings do not have the massive full-chest hypertrophied pectoralis necessary to generate lift, and are glide-capable at best.

[Starglider]

[A six-limbed "angel"-form flying humanoid is impossible. The main flying muscle in birds is the pectoralis muscle, and it's hypertrophied compared to humans: up to 15% of a flying bird's body mass is taken up by the pecs. The wings are literally pulled downward and in across the chest by nearly a quarter of the bird's mass in dense fast-twitch muscle.

In principle, you could use muscles running down through the torso, parallel to the (fused) spine, and a tendon/pulley or lever arrangement at the wing joint. Essentially at this point you are completely redesigning the skeleton and musculature, within the constraint of roughly human external contours. Of course, you would have to use muscle tissue with several factors better power-to-weight than human muscles to make this work in earth-like gravity, and unless that gain comes purely from improved thermodynamic efficiency you'd need superhuman organ systems to support them.

[Junghalli]

Ya borked the link matey. I'm not seeing anything

This should work:

Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments

Edit: as far as the flying humanoid thing goes, one obvious solution in this case is to suggest the kokome were designed to operate on a world with a thicker atmosphere and lighter gravity, like Blue Moon. That should make flying much easier. It's still a fairly silly design, but if you assume they were designed for something that was more like a ritualized tournament than actual war it might work.

[Terralthra]

In principle, you could use muscles running down through the torso, parallel to the (fused) spine, and a tendon/pulley or lever arrangement at the wing joint. Essentially at this point you are completely redesigning the skeleton and musculature, within the constraint of roughly human external contours. Of course, you would have to use muscle tissue with several factors better power-to-weight than human muscles to make this work in earth-like gravity, and unless that gain comes purely from improved thermodynamic efficiency you'd need superhuman organ systems to support them.

That could work. Basically, one would be repurposing the spinal erectors to pull the wings through a lever action instead of pulling the torso up/back. This would naturally mean that the torso is immobile, severely hampering walking (since torso movement is a large part of maintaining bipedal balance).

Another idea would be to fuse the spine (again), and move the wings down the back to the abdomen. Then one could basically replace the abdominalis (which only exist to pull the torso and/or hips forward) with a second set of pectoralis intended for the wings. This would entail extending the breastbone down into the abdomen and stabilizing it with more pairs of ribs. One could also do this with the arms, leaving the wings at the shoulders.

Edit: as far as the flying humanoid thing goes, one obvious solution in this case is to suggest the kokome were designed to operate on a world with a thicker atmosphere and lighter gravity, like Blue Moon. That should make flying much easier. It's still a fairly silly design, but if you assume they were designed for something that was more like a ritualized tournament than actual war it might work.

That doesn't really work. For one thing, less massive worlds (lower gravity) tend to have thinner atmospheres (lower air density), not thicker. See Mars, Titan. These are directly related: holding a thicker atmosphere requires more gravitational force.

Even if you were to magic up a thick atmosphere on a low-gravity world, there's still the magnitude problem. We're talking about somewhere on the order of 2-3 orders of magnitude here. You'd need a world with < 1 m/sec^2 gravity and air ten times thicker than Earth's to even get close. On such a planet, it's doubtful humanoid life would evolve at all.

[GrandMasterTerwynn]

That doesn't really work. For one thing, less massive worlds (lower gravity) tend to have thinner atmospheres (lower air density), not thicker. See Mars, Titan. These are directly related: holding a thicker atmosphere requires more gravitational force.

Minor nitpick here, Titan's atmosphere is actually nearly four times as dense at the surface as Earth's. It is, however, much, much colder, so the atmospheric gases aren't as apt to go zooming off into the vacuum of space.

[Terralthra]

Mea culpa.

[Lord of the Abyss]

I sit corrected.

On the other hand, bird skeletons are not humanoid; they're much better optimized for flight than the skeleton of a winged humanoid of the "angel" type. If we took a bird and tack on a bunch of unnecessary arm and leg (to convert a four-limbed bird with wings stubby little legs into a six-limbed creature with long arms, long legs, and wings)... we're adding weight. To compensate, we either have to bulk up the flight muscles, which are already huge in birds, or we have to lighten the skeleton.

The lightening will probably be in the arms and, to a lesser extent, the legs- the legs still have to be able to support the body weight.

Reminds me of the "Angels" of the Titan trilogy; they were emaciated.

That said; couldn't you just make them short? Surely it's easier to make a 2 foot tall flier than a 6 foot tall one.

[Commander Xillian]

... Midget Angels?

BRILLIANT!

[Junghalli]

That doesn't really work. For one thing, less massive worlds (lower gravity) tend to have thinner atmospheres (lower air density), not thicker. See Mars, Titan. These are directly related: holding a thicker atmosphere requires more gravitational force.

Venus is (a little) less massive than Earth and holds onto an atmosphere two orders of magnitude thicker; Earth-mass worlds evidentally have plenty of margin for being able to hold onto much bigger atmospheres than Earth does. Going by that the idea of a lighter gravity world with an atmosphere a couple of times denser than ours doesn't seem implausible. I could be wrong though, somebody who knows more about the relevant physics please correct me if I am.

Anyway, you don't necessarily need lower gravity, just thicker air. Higher oxygen would probably help too.

Even if you were to magic up a thick atmosphere on a low-gravity world, there's still the magnitude problem. We're talking about somewhere on the order of 2-3 orders of magnitude here. You'd need a world with < 1 m/sec^2 gravity and air ten times thicker than Earth's to even get close. On such a planet, it's doubtful humanoid life would evolve at all.

What are the assumptions behind that calculation?

[Terralthra]

My assumptions are human-sized and roughly human-density bodies with human-equivalent muscular weight-to-power ratios. I also assume that the length of the wing can not be more than the height of the human at the shoulder (1.6 m, give or take), and it can not be wider than the body (0.7m, give or take).

Given those dimensions (2.24 m^2) and a max wing-loading of 25 kg/m^2 (from a study I can't find online in English), that leads to a max humanoid flying human of 56 kilos. The average human of 1.7-8m weighs 1.5-2 times that. Add to this that this "average" human does not have the pectoral muscle mass devoted to moving these massive wings that a bird does. In birds, that's somewhere around 15% of body mass, but that's not taking into account that a bird doesn't waste so much of its mass on moving around with legs nor does it have such a large brain, and it's also not taking the wings themselves into account for weight (usually another 20-30% of body weight there). A human-sized angel-shaped flying specimen would almost have to weigh twice as much or more as a non-flying human, and a normal human was already twice as heavy as a flying creature its size could afford to be, even assuming a human shape is aerodynamic and a lot of other ridiculous physiological assumptions.

So, your average angel-type is 4+ times as heavy as a bird its size could be. In practical terms, a bird (now extinct) weighing as much as a human (70-80kg) had a wingspan of 6-7m, and almost all of its 70-80kg were devoted to flying. Doubling the wingspan to account for the nearly double-weight of dragging a humanoid lower body around leaves you with a wingspan nearly ten times that of angel-form humanoid fliers, but in order to double the wingspan, you need to more than double the muscle mass (to be able to exert the same force at the wing tip) and increase the density/thickness of the bone structure...you can see how it's knock-on effect after knock-on effect.

I don't have all the numbers handy that show it's two+ orders of magnitude, but I think I've shown enough.

[Junghalli]

I think the assumption of a weight above 56 kilos is unnecessary. 56 kilos is 123 pounds, which is within shooting distance of normal human weight, if quite a bit on the light side. Even taking out 15% of the mass for the flight muscles gives us 47.6 kilos or ~100 pounds for the rest of the body. Take another 30% for the wings ... heck, let's just take 50% of the body's mass for the flying stuff, that leaves us ~30 kg or ~60 pounds.

As for the wing area being restricted by height at the shoulder, maybe the right wing architecture could help with that. I'm sure there's some way that you could engineer a wing that can fold itself along the short axis.

A 120 pound pygmy angel with all but 50 pounds devoted to flight (i.e. ~60% of body mass devoted to flight) sounds relatively reasonable to me. Of course it'd be child-sized and possibly rather frail and weak pound for pound compared to baselines if we compromise on things like bone strength and muscle mass to lighten the body, which is pretty far from Skeeter's wank. The body would probably also look rather alien/deformed to baseline eyes.

[Simon_Jester]

A six-limbed "angel"-form flying humanoid is impossible. The main flying muscle in birds is the pectoralis muscle, and it's hypertrophied compared to humans: up to 15% of a flying bird's body mass is taken up by the pecs. The wings are literally pulled downward and in across the chest by nearly a quarter of the bird's mass in dense fast-twitch muscle.

In humanoids, the pectoralis muscles work with the trapezius to do almost any movement involving the arms.

Ah. A point. You'd have to turn the underlying muscle structure inside out to get it to work.

Of course, in birds the wings are an adaptation of the arms, so it's no surprise that the arm-placement pectoral muscles got adapted to flap the wings. You'd need a completely different ancestry to get a six-limbed winged "humanoid," say, one that started with four arms and adapted two of them for flight.

And the odds of it looking even slightly human would be right around zero, given those origins.

[Terralthra]

120 lbs is extremely light for an adult male human. The 1.6m shoulder height is indicative of a 1.8m tall human - 5'11". I'm 6'2", and extremely thin, and I'm 165. The 'average' male is apparently 190 lbs, 5'9".

That aside, the wing area restriction by height at the shoulder can be gotten around by a folding architecture, as is done regularly in birds and bats; however, doing so makes the wing intrinsically weaker in terms of overall strength. To counteract that, we'd need even thicker, heavier bones and denser musculature: even more weight. Keep in mind the square/cube rule: as we make the bone twice as thick, it weighs four times as much.

The problem with the pygmy angel concept is that compromising bone/muscles in the lower torso to allow flight is essentially what birds have already done, except they just got rid of the useless parts instead of carrying vestigial humanoid legs around. In humans, the quadriceps are the biggest, most powerful muscles, because they bear the brunt of walking; the femur is the biggest, densest structural bone, for the same reason. Compromise those, and the pygmy angel can maybe - maybe fly, but it can't *walk*. Its legs would be too long to be structurally sound if we constrain it to humanoid proportions.

The basic point here is that attempting to engineer a flying apparatus onto a body that has evolved for walking is a losing proposition. If you really truly need a flying warrior, and have the genetic engineering knowledge exhibited in grafting near-worthless wings onto a humanoid shape that can therefore no longer walk and has lost most of its ability to use its arms (see above re: pectoral muscles), then you would be better served by engineering hawks to use guns and have a group-based martial strategic mind.

[Starglider]

One design I came up with for flying humanoids was to have weak wing muscles, but conductive feather equivalents charged up to high voltage by electric-eel type cells. By using three or more alternating wire arrays (perpendicular to the airflow) out of phase with each other, you can ionise and then accelerate the boundary layer airflow. This is a real R&D concept for aircraft (mainly UAV) propulsion, though AFAIK it hasn't gone past small scale prototypes. Unfortunately conventional biology just can't handle the power output or insulation breakdown voltages required, even assuming the optimistic claims about thruster efficiency are correct. It would look really cool though, at least at night, due to glow from the corona discharge plasma.

[Junghalli]

120 lbs is extremely light for an adult male human.

Well, I was thinking more of being within the ballpark of a small female human.

That aside, the wing area restriction by height at the shoulder can be gotten around by a folding architecture, as is done regularly in birds and bats; however, doing so makes the wing intrinsically weaker in terms of overall strength. To counteract that, we'd need even thicker, heavier bones and denser musculature: even more weight. Keep in mind the square/cube rule: as we make the bone twice as thick, it weighs four times as much.

Since you're basing wings as a percent of body mass off birds, shouldn't that be already accounted for? Although there is the issue of scaling up from relatively small bird or bat wings.

The problem with the pygmy angel concept is that compromising bone/muscles in the lower torso to allow flight is essentially what birds have already done, except they just got rid of the useless parts instead of carrying vestigial humanoid legs around. In humans, the quadriceps are the biggest, most powerful muscles, because they bear the brunt of walking; the femur is the biggest, densest structural bone, for the same reason. Compromise those, and the pygmy angel can maybe - maybe fly, but it can't *walk*. Its legs would be too long to be structurally sound if we constrain it to humanoid proportions.

What about if you make its legs, say, about as long as the arms?

The basic point here is that attempting to engineer a flying apparatus onto a body that has evolved for walking is a losing proposition. If you really truly need a flying warrior, and have the genetic engineering knowledge exhibited in grafting near-worthless wings onto a humanoid shape that can therefore no longer walk and has lost most of its ability to use its arms (see above re: pectoral muscles), then you would be better served by engineering hawks to use guns and have a group-based martial strategic mind.

Yes, obviously, at this point I'm just curious about whether it could be done.

[Lord of the Abyss]

120 lbs is extremely light for an adult male human.

Well, I was thinking more of being within the ballpark of a small female human.

Look at the smallest functioning adult human beings; those give you a maximum minimum size for an intelligent being using Earth biology. So, we are talking more 30-40 pounds not 120. Making them lighter also helps with the "weak legs" problem others have mentioned; a much lighter body takes much weaker legs to support it.

As for calling them "pygmy angels"; I think they'd probably look more like some kind of creepy fairy. Really small, with really skinny limbs and probably a prominent bone structure.

[LadyTevar]

Look at the smallest functioning adult human beings; those give you a maximum minimum size for an intelligent being using Earth biology. So, we are talking more 30-40 pounds not 120. Making them lighter also helps with the "weak legs" problem others have mentioned; a much lighter body takes much weaker legs to support it.

As for calling them "pygmy angels"; I think they'd probably look more like some kind of creepy fairy. Really small, with really skinny limbs and probably a prominent bone structure.

My thoughts were more along these lines as well -- small and somewhat lemur-like, with the ability to walk bipedal or quad as need be. If the wings are articulated similar to a bats, the wings could act as extra legs in quad-mode.

A more arboreal species might have hooks on the alar joint, used similar to the prehensile tails of New World monkeys. Even a small hook on the tip of the longest wing-strut could expand reach, allowing an arboreal to reach that one fruit out of arms-reach. The legs and other wing would act as stabilizers for that stretch.

[Commander Xillian]

I think making these Dragon- or Imp-like is deviating too much from the Ab-human template.

[loomer]

Hmm. What if we turned the 'humanoid' concept on its side a little and didn't give them arms, and instead gave them a good range of motion in their tiny legs, and flexible manipulators for feet (maybe not to the level of human hands, but it'd be something)? That way we could cut out weight from the extra pair of arms, preserving some of the leg strength in turn, and while it would hamper movement and tool use, for a species that is designed by us that isn't as much of a problem as a naturally occurring one.

It'd also mean the things would do sort of a flappy hop to walk from the kitchen table to the dinner table, which would be both hilarious and adorable.