I'm looking for a story which has these elements: There is an alien species whose biology compels it to reproduce every couple of years, and they don't have a choice about it. As they develop technologically, the population rises faster and faster until civilization falls again and a period of darkness comes to the world. They try various ways to prevent it - drugs, infanticide etc, but they've never been adopted by the whole world, so civilization keeps rising and falling. There is also some mention of different varieties of the aliens - soldiers, medics, etc. and perhaps trying to eliminate certain versions to reduce the population pressure.

The story takes place during a period of high technology. The main characters stumble on an ancient subway line which has somehow survived.

I read it in the 90s, but it could have been written quite a while earlier.

marked as duplicate by user14111 story-identification Aug 22 '17 at 2:48

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This was a passage (Chapters 33 through 38) from Niven and Pournelle's The Mote in God's Eye, when the three midshipmen (Staley, Whitbread and Potter) are forced to the planet's surface. They learn too much about the Moties to be allowed to survive.

  • Actually they learned too much to be allowed to return to MacArthur. The Moties wanted to take them alive, but failed to do so. – Kyle Jones Dec 21 '16 at 0:54

The Mote in God's Eye is a perfect fit for your description except for the business about many suns--- that part makes me think of Asimov's short story "Nightfall." However, population pressure wasn't the cause of the periodic collapses of civilization in that story. Maybe your memory is a conflation of Mote and "Nightfall." Both stories are well worth your time to read if you haven't read them already.


I seem to recall that in "The Mote In Gods Eye" the aliens were unable to leave their system the fast way due to interstellar jump technology taking them into the interior of a neighbouring huge red giant star (the eye) of which their companion system was the mote. Thus all their attempts to explore the universe ended in burning up. This kept them bottled in and reinforced the cycle of the repeated rise and fall of civilisations. The OP may be thinking of this part of the story in connection with multiple suns which is definitely an important part of the book. It was a moral dilemma for the humans as to whether to let them out. Very interesting book by the way....


This sounds like one of the key scenes from The Mote in God's Eye by Larry Niven and Jerry Pournelle. The aliens are called the "Moties" and, in addition to being specialized by roles as you mention, they have three arms: two on one side and one (much larger) on the other. Sound familiar?

Since a couple of other people have chimed in with the same ID, I don't think it's necessary to type out the excerpts -- this is probably what you're looking for. I'm also pretty sure this would be a duplicate somewhere.


I remember reading it, too. Definitely "The Mote in Gods Eye". The FTL mechanic technobabbled something about thermonuclear pathways between stars. "Gods Eye" was a particular star (or was it a cluster of stars?) that hadn't been explored yet since getting to it turned out to require entering a star's atmosphere (very hot despite the Langston Fields) in order to establish the FTL pathway. If I'm remembering correctly, there was some kind of subway system that they used when they got to the Motie's planet. That subway line was an artifact from a previous rise-fall cycle on their planet.

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