Maybe I've missed it in my marathon readthrough of the Ringworld series, but I can't understand what the Kzinti are doing on the Ringworld. The Protectors went to enormous lengths to make the breeders safe - they flew them out a jillion light years from the galactic core, built a Ringworld out of a gas giant, got rid of all their predators and disease...and then populated a whole map full of killer sentient carnivores. And not just any map, but a map right next to the Map of Earth, which is populated with hominids.


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    Because the sequels are bad? Commented Aug 11, 2014 at 2:36
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    While agreeing with @OrganicMarble, one could point out that it was just a limited section of the ring dedicated to reproduce worlds "in the wild", and that section was isolated from the rest of the ring (which was human -and derivatives- only). Also, it is stated that the distance between "worlds" by sea is so big to be very difficult to sail through, probably the idea was that the (missing) protectors would have kept Kzin technologic levels down.
    – SJuan76
    Commented Aug 11, 2014 at 7:38
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    Well, I didn't think they were too bad. :) @SJuan76, the problem I have with that is that I would expect that the Protectors would annihilate the Kzin upon discovery of their homeworld, not give them a lift to the Ringworld...they were supposedly xenophohic and went out of their way to reduce risk. They wouldn't have any reason to care about a "nature preserve" of non-Pak, just the opposite. And of course, that assumption was illogical - wooden sailing ships can get pretty dang far.
    – Shamshiel
    Commented Aug 11, 2014 at 11:25
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    I'll have to check when I get home, but I thought the kzin indeed already colonized the Map of Earth before Chmee and Louis came into the picture. Either way, we're still left with the question of why on earth the Pak would have brought them there.
    – Shamshiel
    Commented Aug 11, 2014 at 14:46
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    @Richard: It has more to do with the risk-averse nature of Hollywood executives than the writer's strike, which only affected television, and ended six years ago. I am aware of the decline in cinema-attendance. But Hollywood can largely blame themselves for that. Look at the changes to Ridley Scott's last two blockbusters, Prometheus and Robin Hood. Alien: Engineers and Nottingham were two of the best screenplays in recent memory, but both were altered into utterly forgettable, sub-par films. Commented Aug 12, 2014 at 1:46

2 Answers 2


I've removed the spoiler markup since the OP has read the series. Fair warning.

In chapter 15 of Ringworld's Children, the Pak protector Proserpina described how the Ringworld came to be. Of the flattened maps of various worlds she had this to say:

"Stars that can generate extensive planetary systems form in clusters. There were stars with planets around us where we stopped, and some were Pak-like or close to it. We identified those that might evolve dangerous enemies. We collected local ecologies and settled them on maps of their worlds."

This matches what Chmee deduced in The Ringworld Engineers:

Chmeee snorted. "Obvious to the meanest intelligence, Louis. It is a roster of potential enemies, intelligent or near-intelligent beings who may one day threaten the Ringworld."

The roster, laid out in maps on the Ringworld itself, was designed to provide information useful to an illiterate, newly awakened Protector. As maps with obviously transplanted ecologies, the information was presented in a way that could be deduced intuitively.

On the larger issue of why Protectors would permit dangerous species on the Ringworld, the maps have to be understood as part of an experiment undertaken by a large number of Protectors trying desperately to break the cycles of interstellar expansion and warfare that threatened to end their species. Summarized from Ringworld's Children, this group of Protectors set out to do two things: 1) separate themselves from the rest of the Pak race, and 2) breed out the monomaniacal and xenophobic traits that made them a menace to themselves and incidentally to every other living thing not immediately beneficial to their breeders. They built a cylindrical ship ala Rendezvous with Rama containing an ecology, their breeders and themselves, with the breeders completely walled off from the Protectors. The penalty for any direct contact with breeders was death. Some breeders died without their Protectors to help them. Some Protectors stopped eating because they felt purposeless without contact with their breeders. Some Protectors tried to sneak into the breeder section of the ship and were caught and killed. Eventually, as Proserpina described it:

"What emerged at the end of three hundred and fifty thousand falans of travel, was a race that can live without the smell of our own blood line constantly in our nostrils."

The surviving kinder and gentler Protectors then constructed the Ringworld and tried to run it under the same model of governance, with Protectors and breeders strictly separated. Protectors who violated the rules were killed or imprisoned with a sampling of their breeders, with no technology that could disrupt the status quo.

According to Proserpina, these early pioneering Protectors could have seized all the worlds of Known Space, but their ambitions were greater than that. Instinctual conquest and slaughter were the traits they were trying to breed out of themselves. So they built the Ringworld and sequestered themselves there.

The enforced peace lasted for a long while but all things end. Fighting broke out among the remaining Protectors, with an eventual victor or victors controlling the Repair Center. But these victors did not feel the urge to slaughter all but their own bloodline. So the wild mutations among the humanoids into various ecological niches and the map worlds of aliens were allowed to grow and develop unimpeded.


Based on the Larry Niven passages that the "new" Protectors where trying to breed out Xenophobia from their blood lines, then the bringing of th Kzinti to the Ringworld would make perfect sense. They provided that Protectors with endless supply of "other" to experiment on and achieve their goal of non Xenophobia. Perhaps they saw the potential benefit of other species existence to their own, or they where just keeping them as ways to experiment on ways so Pak would not kill Pak. In the same way, say as humans keep animals to test cures on. If the later is the case, the worlds they came from where not yet near threats, and could be destroyed at anytime, but where keep as sources of genetic material if the need arose. As said, the "new" Pak where not driven killing machines of old.

It is not clear of course that Kzinti where taken to the Ringworld, only their ecologies. The ecologies could have been taken at a pre-Kzinti evolutionary state, and that the Kzinti are just a case of parallel evolution, like the Spill Mountain people. With perfectly matching ecologies, the same genetic material in the mix, and a near perfect world copy, it would not be surprising that the Kzinti would evolve on two worlds. We already know that the Kzinti of the Ringworld are not identical to that of their home world, we just do not now how far ago they branched off.

-- Ed Scholz

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    Weren't the female Kzinti on the Ringworld actually intelligent while that trait had been bred out of them in Kzinti space? Commented May 18, 2016 at 19:41

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