Making bipedal aliens more "alien"

[LmThomas]

I want to have bipedal aliens in my story but I feel they are unrealistic. Has anyone else felt this way? If do what did you do?

 

[Laeraneth]

Well, they're obviously realistic. To a true alien species, WE would be the bipedal aliens.

I assume you mean more that they're too obvious because everyone does it? (for many reasons, good and bad )

I've not gone into the deep realms of sci-fi in any of my writing yet, but I've considered such ideas for years. Bipedal nature has a couple of obvious benefits that would lead to sentient races tending towards that. Namely: the freedom of a pair of limbs to use tools accurately and thus eventually advance technologically; versatility - we can still use all four limbs to clamber over things and defend ourselves, but we aren't restricted to it.

There's nothing to say that a quadrupedal race couldn't develop similar tools and tech while sitting, but they couldn't actively USE such things while moving if they have to use all their limbs for motion.

In short... bipedal sentients (of the sort that might become space-worthy) seem to be a relatively sensible assumption.

However, it's your story! There's nothing to say that a six-limbed race couldn't exist somewhere and develop in comparable ways to us (think Centaur). Perhaps an aquatic race could develop some sort of technology that would allow them to become spaceworthy? They would have absolutely no need for limbs for motion as we use them and could be multi-limbed squid-like creatures.

(there may well be good physical reasons why a six-limbed creature of our size couldn't exist and prosper... probably something to do with skeletal complexity... which might be less of an issue in a lower gravity environment?... hopefully some qualified biologist will come along and inform )

 

[Parson]

For me as a reader the question of alien or not has much more to do with the way the alien thinks and reasons, the way their society is arranged in terms of what is important, what is scandalous and things like that.

I think C.J. Cheeryth has written some of the very best aliens in S.F. and you will note that most of those are bipedal. But they are clearly and incontrovertibly alien.

I would guess that your displeasure with you bipedal aliens comes from either the sometimes mockery of T.V. and Movie aliens, which are very often bi-pedal, especially before computer animation, or your own sense that what you are writing is not really alien. Writing convincing aliens requires extensive world building which is only sometimes seen in the writing.

 

[JonH]

(there may well be good physical reasons why a six-limbed creature of our size couldn't exist and prosper... probably something to do with skeletal complexity... which might be less of an issue in a lower gravity environment?... hopefully some qualified biologist will come along and inform )

I'm not a qualified biologist (or indeed exobiologist) but if there are two-metre bipeds, and two-metre quadrapeds and two-metre octopods (the now extinct eurypterids or sea scorpions grew to about eight feet - appropriately), there is no biological reason that hexapods couldn't.

That insects have never reached this size is because of factors other than the number of legs -- such as their method of respiration which becomes inefficient beyond a certain size.

 

[Venusian Broon]

I'm not a qualified biologist (or indeed exobiologist) but if there are two-metre bipeds, and two-metre quadrapeds and two-metre octopods (the now extinct eurypterids or sea scorpions grew to about eight feet - appropriately), there is no biological reason that hexapods couldn't.

That insects have never reached this size is because of factors other than the number of legs -- such as their method of respiration which becomes inefficient beyond a certain size.

My limited understanding of evolutionary biology is that the reason that the four limb animal models (and thus includes: two leg-two arm, four leg, two leg-two wings format etc...) that are really dominant from amphibians upwards*, is because limbs are really evolved fish fins and fish evolved to have fins in the places that they did to maximise their hydrodynamical efficiency. Or to put it anther way the fins were in the optimum places for movement in water.

So one could argue that the four limb animal model might be replicated on other worlds because it is a physical solution to an environment (essentially fluid!) that is highly likely to be universal for life.

Well, I say might. What's to stop insect-like aliens with 6 legs evolving a much better method of respiration?

* There are of course notable exceptions, such as snakes or aquatic mammals that have gone off-piste and lost limbs

 

[Mirannan]

Well, I can think of a few ways bipeds could be a lot more alien than the ones on Star Trek - for example.

Making them furry or scaly (or even feathery) for a start. Herbivorous or carnivorous. Based on a different body plan; to take a possible example from Earth, it is thought that some of the dinosaurs were warm-blooded and possibly feathered. So reptilian, avian or even amphibian bipeds might be possible - or, of course, something for which there is no Earthly analogue.

Another possibility is a species with so much more sexual dimorphism than humans that the species might just as well be asexual - like angler fish are in the real world, and Niven's kzin have nonsapient females. (The Lensman series features a race of which the females look just like Earth humans but the males are of very limited intelligence and violent bent, just to redress the balance.) One where the nurturing of offspring is turned around so that the biological males carry the babies and look after them after they are born - this has already been done in fiction.

Or possibly races that need either trace amounts of something nasty (to us!) like cyanide or arsenic, or even have completely different body chemistry - either using water as we do, but using some completely different molecule as genetic material, or even using something different as a solvent - liquid ammonia maybe.

Just a few ideas...

 

[JonH]

True VB, but it all gets complex in the sea. Giant Squid have eight arms, two tentacles and no legs at all! If we discount arm and tentacle length, they're about two-metres, too. So when we are talking fins, we're just going out on a limb.

I'm gonna watch Farscape now, with bipedal aliens, even bipedal plants. I don't care how "real" they are.

 

[Venusian Broon]

True VB, but it all gets complex in the sea. Giant Squid have eight arms, two tentacles and no legs at all! If we discount arm and tentacle length, they're about two-metres, too. So when we are talking fins, we're just going out on a limb.

I'm gonna watch Farscape now, with bipedal aliens, even bipedal plants. I don't care how "real" they are.

I agree J, although in the broadest sense surely whether a limb is an arm or a leg is really just a naming convention based on what the animal uses it for (I think) - for example:

Octopuses have two legs and six arms - Telegraph



Decades ago there was a programme on the telly that asked scientists to imagine what might evolve on earth - and I really like the idea that they had of squid-like animals make the transition from the sea to land. So at one point they had CGI'd troupes of 10 legged (or is that 10 armed???) 'squid monkeys' jumping about the trees.

---
This does not solve the problem of making bipedal aliens more alien, but...

Another possible idea for 'far out' and radical alien morphologies might be a looking at extensions of eusocial animals - i.e. termites, bees and ants. So you have super organisms that are made up of thousands and thousand of individual animals that individually are weak, but put them together and they thrive.

Perhaps imagine an alien eusocial super animal where intelligence is not present in any of the individual animals (whatever they are) but somehow emerges through the eusocial interactions. I'm pretty sure I've read a couple of short stories where people have explored this idea.

I'll get my coat...

 

[JonH]

Perhaps imagine an alien eusocial super animal where intelligence is not present in any of the individual animals (whatever they are) but somehow emerges through the eusocial interactions. I'm pretty sure I've read a couple of short stories where people have explored this idea.

I'll get my coat...

Perhaps Nigel Farage is an alien eu-antisocial animal.

Coats all round.

Actually, my first abortive attempt at a novel had aliens just like this. The underlying animals within the group didn't even have to be of the same species. They sensed each others mass, and their relative movement became both thought and communication. The more they built up levels of complexity, the more intelligent they became.

 

[Null_Zone]

Make the aliens avatars of something that barely understands hummanity beyond its general shape. Something we don't even understand the medium it exists in.

 

[paranoid marvin]

People have it so ingrained into them that aliens are bi-pedal that no-one is going to question if yours are. Unless you're writing a scientific or biological dissertation (and I'm guessing you're not) then it doesn't really matter.

The thing is that you're writing an interesting story. The aliens could be 20 foot high with tentacles waving all about the place, but you're going to struggle to get them into a story were they communicate intelligently with humans. Making them broadly similar in size/shape to humans means that they can interact with humans and your story can continue. Unless it's a key part of the tale, then it hardly matters what they look like; what is important is how they think and act - that is what makes them 'alien', not how many legs or arms or heads they might have.

If it concerns you, then simply have them as shapeshifters, able to adopt a form that is familiar and comfortable to the inhabitants of the planets they visit.

 

[ralphkern]

I suspect the modern view of Bipedal aliens first came from the early books, where simply they went with what they knew, ie. two arms and two legs. It then continued with TV where it simply helped with the cost of production to simply put someone in a suit or give them a funny forehead and that made them alien.

 

[MatterSack]

Land vertebrates have six limbs because, like Venusian Broon said, our common ancestor had four pentadactyl (five-digit) limbs when it evolved to live on land. It didn't need to have four; in fact, it was allegedly more a matter of chance than design that we got four. There were many other creatures at the time with a wide variety of limb structures, yet none of them ever made the transition (excluding small invertebrates like arthropods).

I personally believe that four may have been the most successful due to a locomotive balance between stability and energy-efficiency, but there's no conclusive evidence to my knowledge.



Note however: bipedalism is very rare within the animal kingdom. The exact reasons for our bipedalism are still unknown, but some theories:

• It allowed us to better observe our environments (grassy plains). Those that could rear up to see over the obstructing terrain were more likely to detect predators/prey and survive to reproduce.
  
  
• It granted us cooling advantages. Being perpendicular to the ground ensured that <20% of our bodies were exposed to the midday sun, unlike a quadruped, of which ~70% is usually exposed. Being taller also placed our body mass further from the ground, where the air currents were stronger and allowed better convective heat disposal. Once combined with our thinned fur and incredible capacity to sweat, we were able to venture out during the day when our predators were unable to.
  
  
• It freed our hands and allowing us to better use tools/carry things.
  
  
• Combined with all of the above, it turned us into the best endurance hunters on the planet. By the time of Homo erectus we could outrun any quadruped, not with speed but with perseverance, literally tracking and chasing them down until they overheated.
  
  
• It gave us versatility. We could walk, run, climb and swim fairly well; we weren't the best at any one means of locomotion, but could do everything except fly (which has now been remedied).
  
  
• In the end, it also facilitated us eating meat, which then resulted in a positive feedback loop that resulted in our incredible encephalisation (make tools with free hands and butcher carcasses, eat high-quality diet of meat and marrow which increases brain size, increased brain size allows for better tools and better butchering capability, etc).

Just remember... as long as your aliens have reason to be bipedal then you should be fine.

One idea (like Null_Zone said) would be to make their bipedalism a result of our bipedalism. E.g., they're mimicking our morphology to better integrate or to navigate our man-made environments?

 

[psychotick]

Hi,

I don't see bipedalism as unlikely. It has definite advantages in certain environments. Tool using, the ability to spot enemies at a distance, tree climbing etc. However I don't see it as the most likely form for intelligenceto evolve in.

If we look at our own world, outside of the apes the other brighter animals are elephants, and dolphins / whales. Also octopi. Given how far all of these different body designs have come in terms of intelligence under the prevailing environmental conditions, I see no reason why given the right selective pressure over millions of years creatures with these body plans couldn't achieve human level intelligence even here on Earth.

I think the danger with bipedal sentient aliens isn't their use in books and tv etc. It's the shows where every alien is the same. Farscape is one notable and brilliant exception.

Cheers, Greg.

 

[Bowler1]

Convergent evolution is what I'm going to hang my hat on, seeing all the coats have been taken.

Eyes have developed as eyes a number of times, so evolution likes eyes of a certain model. They may look different, but in general eyes are usually in eye balls, with a hole to let light in on one side. You get the idea.

Anyway... when dreaming up your alien try and keep them functional. The Blob (I loved the movie, but didn't really believe the idea) being a jelly mass on land may have worked for Hollywood, but I'd expect better of the members on this forum. Functional however takes many forms and we've had birds in New Zealand fill a lot evolution gaps on that island, so there is a massive scope for being creative. However, I think most advanced aliens will have evolved from hunters, as hunters have to use the grey mass to stalk pray and will be a more clever animal (a rule, but not a golden rule I'd say). I also think there has to be some spare limbs (our arms) to use tools and weapons to advance our aliens from the stone age onwards. This is why we walk on two feet, as we had found another use for our arms (carrying infants across grasslands to start with, but later spears and other weapons). Naturally of course, fairly large so they can support a large brain. So apply a logic to your alien and think about how they may have developed. The rest is up to you.

By the way, I have large Birds, a Kangaroo/Dog mix and my Many (on four legs, with trunk like arms and about the size of a pig) as the first of my aliens. Only two of the three are bipedal here, so go play and have fun.

 

[Laeraneth]

I've spent whole evenings before trying to think of sensible environmental/biological reasons why a race might evolve with an uneven number of limbs, just to be different (that is, just for me to be different, not the race... that's not a good reason )
Pentapod's I could just about justify in my mind, as there are some creatures that essentially use the tail as a pseudo-third limb or for balance. Thus given enough evolution, I could just about imagine it happening.
Heptapods were trickier, but I suppose if you accept that hexapods should be plausible, given the right environment, then heptapods would be as well for the same reason as the pentapod.

My ideal truly alien species, once I came to that conclusion, was a vaguely insectiod scorpion-like beast with four main legs, a fifth 'central/rear' one that could double as balance/tail and as a third 'back' arm for tool use or combat, with what might originally have been pincers having evolved into something closer to limbs that can manipulate tools properly together at the front.

If I could draw even remotely as well as I could write (ie, passably...), I'd have scribbled one down and posted it somewhere by now

 

[JonH]

I've spent whole evenings before trying to think of sensible environmental/biological reasons why a race might evolve with an uneven number of limbs

According to Wikipedia sea urchins evolved fivefold symmetry to help them bury into sand. That doesn't make a lot of sense to me, but I suppose if I could see one actually doing it, perhaps it would.

I couldn't find a reason why starfish developed radial symmetry, nor why some have seven legs when most have five.

 

[Ursa major]

Eyes have developed as eyes a number of times, so evolution likes eyes of a certain model. They may look different, but in general eyes are usually in eye balls, with a hole to let light in on one side. You get the idea.

I read that there are at least nine different types of eye. And even when they are superficially similar, there can be major differences. For instance, the retinas of vertebrates are back to front: the light passes through the back of the retina -- and thus through the nerves attached to the retina -- before it can reach the light sensitive rods and cones. Humble cephalopods have their retinas the right way round (which means that they don't have a blind spot).


As for bipedalism, my MC finds, in chapter one of WiP1, that she can, in fact, run on all fours. She's rather baffled about this: none of her fellow aliens walk on other than two legs.

 

[Bowler1]

There we go, a Scorpion with an odd number of arms/limbs now feels right. Once a logic of some sort has applied and I/we the reader believe you, then anything is possible. I've honestly never thought that much about starfish, but I'd imagine changing direction and general starfish running away would help settle the evolution of said starfish. Those unable to run away, five, seven or even nine arms, would be eaten and we'd never know about them.


Yay, the Bear is here. Functionally all these eyes still see, which is a generally useful function of an eye. But when designing your alien their eyes can look different, with nictitating membranes, different pupils and any colour you like. Like Predator the movie, they could see far better than we can and in many light spectrums, all the better to chase you down and eat you up. And this is just eyes. There is loads more fun to be had, an all this before Captain Kirk turns up and tries to mate with your freshly minted alien.


I had aliens that generally walked, but when in a rush, hopped along. Some of them smoked and were winded after hopping about, but that is a life style issue and not evolution.

 

[Venusian Broon]

According to Wikipedia sea urchins evolved fivefold symmetry to help them bury into sand. That doesn't make a lot of sense to me, but I suppose if I could see one actually doing it, perhaps it would.

I couldn't find a reason why starfish developed radial symmetry, nor why some have seven legs when most have five.

Here's a paper on this particular subject:

http://arxiv.org/ftp/arxiv/papers/1202/1202.2219.pdf

In it they analysed using mathematical modelling some the differences between different armed starfish. So I suppose take with a pinch of salt. But they looked at odour detection, the ability to turn over, autotomy (ability to lose an arm to escape predation I think) and adhesion.

I think the conclusion that I picked out from it seems probable: That five legged starfish are in general the most optimum shape for all of the traits described above. Different legged starfish may be better at one or two other things (and hence explain why there are starfish who perhaps take advantage of that and have anything up to 15 arms) But 5 legged is the jack-of-all trades and 'safest design'.