Tuesday 31 January 2023

Imagining Roteopia

As a consequence of reading 'Cats Paws' and Catapults' I became mildly obsessed with the idea of rotational limbs in living things. WHY can't we have Segway Elephants and HOW could they evolve????

Thus I developed Roteopia, which is like that series Dinotopia but imagining an earth where creatures with rotating limbs evolved but everything else stayed at least familiar enough for the reader to understand what’s going on.



"By wheels we mean proper wheel and axle devices that can rotate without limit with respect to the rest of a machine. If you roll down a hill, your whole body may be a wheel, but you're no wheel and axle. So we're not talking about tumbleweeds, or about the tiny turds that dung beetles roll homeward for grubs, or about a few crustaceans that get around by rolling as a whole. Nor are we worrying about how far we can rotate our fists around our rms or our heads on our shoulders. By "rotation" we also mean something fairly specific. When you draw a circle on a piece of paper, do you rotate your hand? You may move it in a circle, but you don't truly rotate it; after all, your hand at all times points in the same compass direction. Human dances make elaborate uses of such circular but nonrotational motion, most likely because it doesn't make us dizzy. Not all dances, of course; waltzes are rotational and, one suspects, intentionally vertiginous. The wheels of a bicycle rotate; your feet and the pedals just move around in circular paths. The Ferris wheel rotates as a whole, but the seats and people just go in circles. In this precise sense - excluding both rolling as a whole and merely going in circles - the only known instance of a wheel and axle in nature is the bacterial flagellum." - Steven Vogel, Cats' paws and Catapults

(From a post by u/ExplosiveVent here)


I have two general base animals in mind depend on whether we want bones or boneless. I will start with boned.

So imagine something like a a very early form of the Angler Fish in the Cambrian era. Not quite fishlike yet, maybe flat instead of tall, but it has a spine.

This creature is highly sexually dimorphic. The females are large and the males very small. Pattern of mating is that the male physically inserts its head into one of a range of orifices in the female. This proto-womb has a muscular lock to stop the male getting away. Once penetrated the area around the males head/internal wall, dissolves, large parts of the flesh of the males head dissolve as well, allowing genetic material to enter the female. Now they are joined.

So far, not hugely different to the modern Angler Fish, which can swim around with a number of males attached to it.

At some point the mating biology mutates so that the male can 'spin' inside the muscle lock. It has a particular head shape that keeps its head 'inside' the female, and if it did manage to get out it would die anyway as now it can only gain nutrients from the females body. But it can 'swim', flex its body and turn n its own axis, part inside the female but the rear part outside.

Now we imagine multiple matings, either simultaneously or over time but with the males from previous matings remaining in place.

Now we have a vertebrae fishlike being with these mini-fish sticking out of it, and the mini fish can still swim, and crucially, they can rotate in place.

Now rotational movement, a corkscrewing, is extremely efficient, so all we are waiting for is a fluke where the males are all capable of rotating and in the right position to provide thrust and are sensitive and responsive enough to female pressure to do so on command.

So now we have a fishlike being with what are in effect, corkscrew drives. 

That’s your evolutionary pressure. From this point on the species becomes better and better at developing and maintaining these rotating 'limbs'. More and more of the species existence is spent as an actually-multiple mating group, rotating improves, adaptions to secretions and the inner wall increasing strength and decreasing friction, energy transfer between female and male improves, male body shape shifts to become more and more an efficient corkscrew, the primal rotators develop a flexible body comportment so they can group their 'screws' behind them for maximum thrust but also spread these 'limbs' for manoeuvring. 

So effectively this early fish can 'strafe', and move rapidly three-dimensionally in water.

(The G'Kek from David Brins 'Uplift' series.
They were engineered and don't count.)


The other option for this was a sort of proto-squid with the rotating 'engines' at the end of the limbs. My main difficulty with these was that I want to get them on land at some point and its very rare (maybe impossible) for a non boned creature to evolve bones. Once they get to a certain size on land bones are going to be super-useful for sustaining that weight.

HOWEVER, the squid would have extra limbs, meaning it could 'push' itself along the sea floor, provide extra thrust, and have limbs left over for manipulation and hunting. I do like the idea of a huge hairy wheeled squid mammoth, or colour-shifting high speed steppe predator wheeled squid.


Moving from sea to land would happen pretty much as it did in our world, with colonisation of reefs, rotators using their screws to aquaplane the flat sea by beaches, rotator-lungfish types living in mud etc.

The evolution from screws to wheels should be _relatively_ simple. The males changing from corkscrews to full wheels and the alignment of the limbs shifting.


Once you have even a semi-wheeled animal which can leave the water and race up and down the beach, we are off baby!

This is another situation where it might be easier to start with Squid rather than a vertebrate as they could manoeuvre and 'lock' their wheels, turning their limbs into legs, allowing them to cross rough ground probably easier and sooner than the fish-rotators.

The great difference between evolution on Roteopia and here would be the incredible SPEED of land animals really right from the start.

(Phillip Pullmans seed wheelers


What does evolution on a fast rotation-based world look like? 

Probably the world of Speed will start at the beaches and the river mouths, but could it propagate itself inland? 

I imagine giant slow rotator-dinosaurs CRUSHING their way through primeval forests, eating all the trees and pooping out a steady stream of waste that hardens into a kind of poop-asphalt to aid the way of their baby-rotators.

Could Rotators conquer and in fact synergise with different forms of plant life to create a world not of dense forests but of mixed plain-forest pathways. Plants on flat land more spread out and distributed, wider apart, with high crowns and little midway growth, but with very flat smooth roots that don't disturb the ground (an evolutionary reward bought with the high dispersal of becoming a rotators favourite food).

Or plants and ecosystems which sustain themselves by foiling the rotators, producing crazed root systems, foiling toxic hanging vines and 'trap' branches which fall like caltrops. An environmental war between the rough and the smooth.

The key thing about Rotopia is that things tend to move FAST. Super-fast rotator velociraptors chasing high-speed Stegadons. Propellor driven birds screaming past. Rotator-Orca-Dinosaurs aquaplaning out of the ocean to grab prey.


Yet somehow (because I say so) Humanity arrives and the world ends up looking at least a bit like our own.

What is Rotator Earth like? 

The key difference that I can see is that the plains are now more like oceans rather than deserts. The existence of vast rotator-herds means the plains, tundra and wastes are criss-crossed by desire paths, some perhaps millions of years old, made. An earth of natural prehistoric highways. Prehistoric highways spread like river systems, visible from space, with their own linear ecosystems, resource conflicts over connections and junctions and huge animal traffic jams.

And with Rotator-beasts the crossing of these plains and highways by man becomes much more achievable. Movement across huge distances can be accomplished relatively easily, due to the wonderous efficiency of the hyper-evolved wheeled limb. 

Imagine the maps of early civilisation but now, instead of societies and populations and development being clustered around navigable sea-ports, like the Aegean, Mediterranean, South China Sea, now civilisation has two forms of 'ocean'. Ships travel the sea, linking cultures and resources together, but vast caravans of high speed rotator elephants also travel the plain. Crossing the Sahara, the American plains or much of Mesopotamia is not that big a deal. 

In this world, cultural power comes not just from where seas, rivers and farmable land intersect, but from where the hydraulic web of interconnections itself meshes with the Rotational Plains.

If you have sea-ports, river travel AND a vast plain meshing together, then the plain can be crossed almost as easily as the sea and possibly faster. Now on the far side of that plain, even if there is no oceanic or river access, a new margin of cities and cultures can develop, and at the meshwork between the two systems forms of civilisation can develop which draw wealth and power from a much wider area. Lords of the Land and Sea, Empire multiplied.

High-speed mass chariot warfare - the ancients fighting like a drag race at 50 miles per hour!


  1. Really love this idea. I had a similar idea a few years ago which I posted about but you've put much more thought into the plausibility / speculative science of it. Hope to see this developed further.

  2. Excellent stuff.

    To riff:

    More derived rotational limbs - limbs that throw stones or darts like a pitching machine, limbs that scoop up and sift edibles from soil like a centrifuge, limbs like a chainsaw for rolly-beavers

    Rotating limbs makes utilizing mechanical energy more feasible - gears like a planthopper's or elastic tissues to store the energy in the body - animals that sit by riversides, or windy outcroppings, or rip geysers like bongs to power their leaping and launching - maybe winding up a fellow animal's gear develops a social-bonding importance like grooming does to regular, non-rotating Earth-life - instead of clashing horns & antlers, mating rivals duel with ultra-hard wind-up slaps from paddle-arms

    In addition to your proposed anglerfish-womb development, rotating limbs could perhaps also evolve from the implanted young of a Surinam toad-like brooder, or budding lifeforms

  3. Imagine rodents digging their burrows with a mouth like a bucket wheel excavator. High-speed-moles. Imagine big ones that want to ambush you from below...