Nature creates round objects all the time (stones in a river, a hedgehog in a ball,…), but the principle of an axle is not found as far as I know.
Nature creates round objects all the time (stones in a river, a hedgehog in a ball,…), but the principle of an axle is not found as far as I know.
That’s an interesting point. Rollers were likely in use long before whels-on-axles, and you could argue that those are basically wheels and partly axles, as they rotated freely from the load, and they do the job of both, but neither as well as an actual wheel on a dedicated axle. It was only when the wheel and axle were separated that we got the full benefit.
But good sir, what use is an axle and wheel without whatever doohicky thingamajig that attaches to a frame that transports things or people?
Not sure if you’re serious or not, but wheels and axles are used for a lot more than just transportation. Pottery wheels predate vehicles by about 1,000 years. Windmills and water wheels use interlocking wheels and axles to grind grain. A windlass is essentially just a rope tied to a wheel on an axel for hoisting stuff up, like a bucket in a well.
Not that this matters to the discussion of naturally occurring wheel-and-axle structures. Just an interesting little aside on the value and versatility of wheels.