You, an insectoid alien, have arrived on Earth to discover it depopulated of humans - indeed, every oxygen-breather larger and more complex in cellular structure than an insect has long since gone extinct, in an atmosphere unsuitable for full-sized vertebrate lungs, and in oceans whose occupants are even more desperate, in their own way, for high oxygen saturation and low acidity.
The dominant species of this world, Sol 3, is ants. They comprise more biomass than all other species combined, and as far as fossil records can suggest to you, they have always done so.
You find other things, too. You find megastructures of complexity resembling the ant colonies you have observed. You note that ants can lift dozens or hundreds of times their own mass, in objects, and that they possess great dexterity at carrying objects and traversing surfaces. You observe the way they handle corpse disposal - how little remains, after they've scrapped everything edible, and how it decomposes quickly under the attentions of other organisms in the soil. You've seen the bones of other creatures, but you don't assume they're of an import - why should you, when it's so obvious that there used to be a grand society of giant ants, so very like yourself? They obviously went extinct like all the endoskeleton-possessing megafauna, which you suppose the ants must have used as livestock.
You find books. It takes some time to figure out the languages - so many of them! - but it makes sense. Pheromone-based communication only lasts as long and reaches as far as it is perpetuated, like any oral history, and literacy is one of the hallmarks of an advanced society. The stories are a bit strange, of course, but you can recognise resemblances to your own mythologies and histories. One story tells of a little red ant who is carrying food from a cache to the queen, but gets lost along the way and encounters a big bad wolf spider which apparently evolved some mechanism of aggressive mimicry. The wolf spider mocks the red ant, deceiving her with his many large eyes, mistaken for the queen's compound eyes. He imitates the queen's mandibles with his venom-dripping chelicerae, and he waves his forelegs around to resemble the queen's antennae. Soon enough, a parasitic wasp comes along and cuts down the spider, and the little red ant is able to return to the colony safely with her bundle of goodies.
You feel a little sorry for yourself, not getting to meet this fascinating people before they faded from the pages of time. Their stories are so refreshing, so relatable, so readable! You wonder, sometimes, why you never found any illustrations by these giant ants, of themselves, when so many of their books are full of pictures of their livestock, who they adorned with colourful textiles as a marker of ownership, to tell their animals apart from one another. The story of the little red ant features charming art of a bipedal pack animal carrying a woven container in its graspers, and wearing red livery to match the carapace of its herder.
Everybody knows that endoskeletons are incompatible with higher cognition, since they complicate the moulting process too severely and limit the lifespan of the individual to a few dozen years, rather than the hundreds achievable by insectoids and crustaceans, whose lifespans are limited by the strength needed to break out of increasingly tough shells and keep moulting into larger ones. Chordates' brains can't get any bigger, once they reach their adult size, but at least they're easy to domesticate. You look closely at those graspers - they look rather dexterous! - and you amuse yourself by imagining what sort of stories the vertebrate bipeds would have written, if they had reached ant-tier civilisation before going extinct. That, however, is a concern for a xenohermeneutics expert, or perhaps a science fiction writer, and not you, an interplanetary archaeologist.
Iron Noder 2019, 14/30