Free Statesman by Piers Anthony

canines I had come for. There was Canis dirus , a primitive wolf, and of course Amphicyon , the primitive dog that surely was the wolf's match. There was the Eocene's Mesonyx , perhaps the earliest canine, though the line can be hard to draw. “How are they for guard duty?” I inquired.
    “There are some problems,” the guide confessed. “The primitives are less intelligent than the moderns, and their pack instincts less developed, which means that they are slower to accept the principle of mastery. The truth is, the modern breeds remain the best guards.”
    “But you don't breed superior modern canines?” I asked.
    “We breed only the types specified,” he said.
    I exchanged a glance with Spirit. Here too, the nomenklatura dominated, seeing to it that no project become too efficient in the pursuit of its objective. That would shortly change.
    We continued to the upper reaches, where gee was less. Here there were enormous and high chambers, reaching to the center of the bubble. These were for the flying creatures.
    We gaped, for there in the air was an impossibly monstrous bird, reminiscent of the fabled roc. "
    Teratornis,“ the guide said. ”The largest flying bird ever to exist. It has a wingspan of twelve feet. But it is a carrion-eater, not a hunter, and cannot operate in confined quarters; it remains a novelty."
    “Flying bird,” Spirit said. “There were larger land-bound birds?”
    “Oh, certainly.” The guide showed us to a closed-off chamber, where a bird taller than a man stood. "
    Diatryma, seven feet tall when he stands up straight, a ferocious predator on small mammals.“ We looked at the massively muscled legs and the huge claws and monstrous beak, and agreed that small mammals would have been in trouble, and perhaps some larger ones. ”But the birds, as a general rule, aren't smart,“ the guide continued. ”They can be trained only marginally—and again, the modern ones are superior to the primitives."
    We started down, to the far sides of levels we had ascended before. We saw the huge Miocene pig Dinohyus , as tall as a man and almost as massive as a hippopotamus, the largest of land-dwelling swine.
    “Now, pigs,” I said. “They are relatively intelligent, aren't they? And with tusks—”
    “They may be our best prospect,” the guide agreed. “The appropriate breeds can be tamed and housebroken, yet remain effective fighters. Of course, again—”
    “The moderns are better than the ancients,” I concluded. We certainly knew the direction to encourage future research.
    We came to the section devoted to the felines. “In many respects, the cats are our most effective present product,” the guide said. “They are unmatched as individual predators, on a pound-for-pound basis, and their natural preference for lurking and pouncing enables them to surprise intruders that would avoid running dogs.” He smiled faintly, for the term “running dogs” remained a popular disparagement in Saturnine circles. “However, they have a tendency to revert to wild behavior, and that can be awkward for the proprietors as well as the intruders.”
    I nodded. Even small cats could be wild, and large ones could be savage. The felines were more independent than the canines, a quality I respected, but an organized society had diminishing use for independence. The Saturn philosophy found it easier to embrace the somewhat slavish, lick-master's-hand attitude of the dogs than the bug-me-and-I'll-scratch one of cats.
    “Don't you have ways to differentiate the friends from the enemies?” Spirit asked. “A cat doesn't have to be friendly, if it knows whom to obey and whom to attack.”
    “We are working with smell,” the guide said. “The cats tend to go into a killing frenzy when they detect certain odors, while other smells tend to pacify them.” He stopped at a box mounted on the wall and opened it. “Here, for example, is the pacification odor. We keep it strategically placed, in case of