I've had this idea for intelligent beasts building a civilization based on human slavery. The humans would handle all the work requiring opposable thumbs and the beasts (haven't decided what species) dominate them by sheer physical ability. These beasts started out as primitive, but developed technology over thousands of years since they started enslaving humans - it isn't that different from the rise of civilization on Earth, except it couldn't be maintained without the involvement of another species. So any ideas for how this could work? I don't think it's comparable to how humans used elephants or horses, since the masters could still alter their environments (and the same goes for historical slavery). I imagine the beasts shut the humans away from any tools when they aren't being supervised, and most humans would be publicly owned instead of chattel, since they could easily sabotage or poison careless masters. Or would the relationship be more symbiotic? The beasts probably wouldn't invent much weaponry, so the domestic humans would rely utterly on them for food and protection. Still, slave armies are common in history and the bow-and-arrow is always a huge advantage, so it's possible that they would be used in such fashion. Also, anyone know primitive technologies that wouldn't require the use of opposable thumbs? Could the beasts build basic structures, even write?