Does humanoid convergent evolution imply similar average stats? ie, if we take an animal and we force it down the evolutionary line towards being humanoid, would the changes that are made make them have roughly the same IQ, Strength, Agility, Constitution. Or would they maintain higher strength...

Another way to look at it is does the human shape and physics dictate that a humanoid beings (including machines) must have a similar average ability in the various ways we can measure them.

Yet another way to think of it is would a dog-shaped reptile/cephalopod/insect/mammal/robot be more dog or be more reptile/etc

The following is my thinking, explanation, and purposes... The above question is what I want answered even though the below poses questions as well, they are in pursuit of the above.

Purpose: I'm trying to create a Tabletop RPG game (and novel) and I'm trying to come up with an easy way to balance that is realistic. It is obvious that if all types converge to an average then this becomes a lot easier.

The types that are potentials it seems to me are;

Mammals | Reptilians | Cephalopods | Insects | Androids

The main stats of consequence are;

Strength | Constitution | Agility/Dexterity | intelligence

STRENGTH - It seems that according to research that Reptiles can produce something like only 20% of the strength of mammals. And on the other hand Humans aren't particularly strong mammals with felines able to output strength at what would be superhuman levels for the same body weight... Insects on the other hand seem relatively strong, wouldn't be able to exist at humanoid sizes due to the lack of strength. It seems to me that an insect would have to evolve to have some sort of strength for it to makes sense, while reptiles might not need to evolve strength to match Humanoid levels. Where as we see humans vs other apes there is a large strength disparity which implies a large loss in strength so any mammal that evolves to be humanoid would be significantly weaker than their animalian kin.

CONSTITUTION - Has to do with Sleep, resistance to infections and damage. From what I know Humans are said to have a very good natural immune system compared to most other animals and many "intelligent" creatures seem to have similar sleeping patterns which seems to indicate that as species becomes more intelligent it needs a more humanoid sleeping pattern. While I don't know of any correlation to infection/physical damage resistance, although might it be that high resistance promotes intelligence in some way? Or perhaps because of our intelligence we are able to treat things better thus increasing our exposure to things which causes resistances to more readily come about and then get past on?

AGILITY - My main worry here is Insects have quite fragile bodies and thus would move slower. Likewise Cephalopods have many limbs and thus might be less agile. The evolution for strength in insects would definitely increase this, but to what extent? Wouldn't an exoskeleton still causes restrictions? For cephalopods, if this is the case then wouldn't that mean loss of limbs?

INTELLIGENCE - Intelligence is largely derived from the ability to provide enough energy to supply a more intelligent brain. It seems then that intelligence is capped at human maximum and if you are going to evolve into a humanoid shape you're going to have to learn how to cook to provide energy for increased brain functionality. Doesn't this mean then that any species that comes up with cooking and is humanoid will just become as intelligent as humans?

I've neglected in the above to talk about androids, which is a similar problem. There seems to be the problem that androids would have maximal strength, dexterity, constitution, intelligence, along with a whole host of traits that we can only dream of, but I question, if they're humanoid and they are working within the same realms of energy consumption would they not have many of the same limitations. Their energy would be limited and their CPU would only be able to process so much, just like our brains. And likewise, if we want light androids wouldn't that also limit them making their average to the above stats very similar to ours? with mostly the same abilities? I mean we could but femtoscopic infrared vision eyes in an android, but that would take space in the skull and the processing ability which seems like it would be considered not all that useful and would be bulky, thus discarded. In the end wouldn't they then just average down to the same statistical averages as biological life forms? Maybe a bit enhanced to optimal, but still limited to what a peak humanoid would be able to do?


closed as unclear what you're asking by StephenG, L.Dutch, AlexP, kingledion, AngelPray Feb 24 '18 at 12:52

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    $\begingroup$ I really don't understand what you are trying to ask. Do you mind trying to make it more clear? $\endgroup$ – L.Dutch Feb 24 '18 at 10:29
  • $\begingroup$ Among the great apes, humans are specialized for endurance; this adaptation is why we have lower muscle mass and muscle density: a chimpanzee has greater strength but much lower endurance. Insects cannot grow to human size because their physiology won't scale -- instead of dissolving oxygen in blood, they use a respiratory system which carries air directly to the tissues, and this puts a hard limit on the size of their bodies. I don't understand the bit about reptilian strength; they are poikilotherms -- their endurance is limited by their metabolism and lack of internal thermal regulation. $\endgroup$ – AlexP Feb 24 '18 at 12:13
  • $\begingroup$ I don't understand the title and first line of the question. But from what I do understand, I think that each of your five 'types' seems like a separate question, as in the 'Anatomically correct series.' I think each one merits its own discussion, if I knew what exactly we should discuss. $\endgroup$ – kingledion Feb 24 '18 at 12:34
  • $\begingroup$ edited. Hope that helps explain what I'm asking. $\endgroup$ – Durakken Feb 24 '18 at 13:08
  • $\begingroup$ after your edit, are you aware that there is not measurable called "stats" in real biology? $\endgroup$ – L.Dutch Feb 24 '18 at 13:53


Muscle strength is equal among most animals.
The differences are:

  • The amount of oxygen and sugar muscle get during activity.
  • The amount of nucleus in each muscle cell.
  • The amount of muscle fibers firing at once(which depends on the nervous system)
  • The amount of stress your bones and tendons can resist before breaking apart, muscles are strong enough to rip apart your bones if they contract all together, that's why many animals have natural muscle inhibitors to match the strength of their skeleton and tendons.

Human strength is nothing special, it's really simple .

large muscles + good levers = high strength

This means your strength is actually very limited by what movements you try to make and how many muscles you can engage.

This also means that taller people are weaker in some movements than shorter people. A pull up will always be easier for a shorter person with shorter arms.

That's why some felines and other animals are stronger at equal weight, they have better levers but only in some specific movements. I mean I bet no kitty can ever hip thrust 800 pounds (360kg) or do 120 calf raises with 1100 pounds (500kg) and sure no cat will ever be able to rack pull 1500 pounds (680kg).

Therefore it's not hard for any animal to match human strength, just give them similar levers and similar weight. You also need to make their nervous system and intelligence equal to match their strength because if you take two people the same size with the same muscles the one with a bigger brain and better functioning nervous system will automatically be stronger.


This depends on hearth rate, lifespan, immune system, strength, food intake, cell regeneration, digestive system, brain activity and sleep which also depends on many other factors.

There are too many variables.


So you automatically need similar intelligence if you want similar strength, and in many people's opinions the only thing that distinguish a person from a wild beast is the ability to cook, so you were probably right on this one.

I mean, all animals in the world can show empathy,hatred and even envy.

They can create artistic structures, communicate, learn new skills, learn tool use and some animals can even mimic human speech but we are the only ones who can cook food.


As for insects, just keep the exoskeleton and give them lungs. The only thing restricting insects from being giant is the fact that they breathe through their exoskeleton. Their exoskeleton is made of Chitin which is lighter more flexible than bone, it might be more prone to being pierced but not broken and it can heal incredibly fast anyway (compared to other animals).

The only problem here is why would insects evolve lung like organs.

About cephalopods, most of them are ambush predators. Ambushes require high speed and agility, so no problem for them.

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    $\begingroup$ Welcome to WorldBuilding Esrien! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Secespitus Feb 24 '18 at 12:44
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    $\begingroup$ If I'm reading you right it seems that it is the case that morphological convergent evolution would produce roughly the same statistics with minor difference that would addressed in other ways... Interesting. $\endgroup$ – Durakken Feb 24 '18 at 13:11
  • $\begingroup$ are you sure muscle cells are polynuclear? $\endgroup$ – L.Dutch Feb 24 '18 at 14:06
  • $\begingroup$ If it were totally 'morphological convergent evolution', all fish would be like sharks. If it were totally 'morphological divergent evolution' we would see extremes of species. The dinosaurs were a result of divergent evolution that was unsustainable in the long run. Too extreme to survive climate change and fluctuating O2 levels. Cockroaches are perfect examples of convergent evolution that have survived billions of years There is always a trade-off between convergent and divergent. $\endgroup$ – Justin Thyme Feb 24 '18 at 16:29
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    $\begingroup$ @L.Dutch Skeletal muscle cells of mammals are, I think. They are formed by cells fusing together to form a fiber. $\endgroup$ – Ville Niemi Feb 24 '18 at 22:35

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