This story is set in the Known Space universe, which was created by sci-fi writer Larry Niven. It is an account of how the Kzinti became a star-traveling civilization.
There was a space-faring species call the Jotoki, who dreamed of creating a star-spanning empire. They were a very inventive and curious species, who learned quickly and rose from primitive beginnings to the grandeur of interstellar travel. They were particularly skilled in the technologies of gravity polarization (inventing the gravitic polarization drive) and genetic manipulation. Due to their unusual biology of having five cooperative brain-nodes, they were also extremely skilled with linguistics and diplomacy.
A strange race by most standards, an individual Jotok resembles large spindly starfish, with 5 arm-like sections each containing a semi-independent brain that operates the Jotok's body cooperatively. The Jotoki begin life as small aquatic creatures, most of which are eaten by various predators. Eventually, five of the survivors will merge to form one collective organism, which grows into a tree-dwelling adolescent. An adult Jotok who desires a family can simply go into the wilderness and "harvest" an adolescent of the proper age, a characteristic that the Kzinti would later find extremely useful. These adopted adolescents would then undergo rigorous education and training to become a full adult member of Jotok society.
With the discovery of gravitic polarization, the Jotoki began to expand from their homeworld. They traveled the immense interstellar distances at sub-light speeds, using their intricate knowledge of bio-engineering to suspend themselves in cryogenic sleep for the long voyages. In time, they forged a powerful empire, maintained by diplomacy, trade, and when needed, military force. The Jotoki were mercantile masters, and their merchants were known as consummate traders throughout the worlds of Known Space. In their desire to continually find new worlds, and markets for their traders to exploit, they ranged far and wide, discovering many worlds and making contact with numerous sentient species.
It is not known exactly when a Jotoki exploratory expedition discovered a habitable planet around the star 61 Ursa Majoris, but they found a fertile planet teeming with life. The average climate was colder and drier than the Jotok were used to, but was certainly within their range of habitability. Even more useful to the Jotoki than the planet itself was its inhabitants; large, furry, sentient, bi-pedal predators, with large fan-like ears, and razor-sharp claws & fangs. The civilization of these creatures had reached the early-gunpowder stage of development, and numerous wars raged between the various feudal warlords. The society of this new species was based mainly upon honor, status, and what the Kzinti called "acting Heroic". Being a "Hero" bears many similarities with the Bushido code of the samurai of ancient Earth.
The Jotoki saw an excellent opportunity in the Kzinti. They had found a species ideally suited to serve as their mercenaries, and they quickly made binding agreements with many clans, warlords, and individual t’kzintar (warriors). The Kzinti rode to the stars in service to their new employers, fighting the Jotoki’s battles for them, winning glory in victory after victory. The empire expanded with each new conquest and its rulers grew immensely rich and powerful, until the Jotoki became the dominant power in their region of space.
With this unprecedented new success and power, something began to happen to the Jotoki that has afflicted every empire that ever was or will be; they started to grow decadent, complacent, and self-indulgent. At the same time, the Kzinti had been learning quickly, assimilating all the myriad new technologies, and honing their battle-skills through fighting the wars of their masters. The political situation on Kzinhome had changed as well; the old warlords were gone, having been replaced by a unified government led by an overlord known as the Patriarch. Many of the Kzinti were becoming dissatisfied with the idea of fighting and dying for the Jotoki, and not reaping the spoils of the conquests for themselves. They also had a steadily growing disdain for a species that would be so dishonorable that it would not fight their own battles.
With the instinctual senses of a predator that can detect the weakest animal in a herd, the Kzinti sensed that the time was upon them to rebel against the Jotok and take their rightful place as the dominant species. Across the Jotok Empire, the Kzinti rose up against their masters, slaying them indiscriminately and without mercy, feasting upon the flesh of their fallen foes. Battles raged for decades across numberless worlds, and many were laid to waste as the Kzinti let loose their long-suppressed rage of being a subjugated species. The Jotoki had a degree of technical superiority, and had been traveling the stars much longer than the Kzinti, but they had grown too complacent to withstand the pent-up fury of the Kzinti onslaught.
As each successive world fell to the brave Kzinti, they enslaved their former rulers and gained new technologies and resources. The outcome of the war was never truly in doubt, and eventually the last Jotok world was taken. The Kzinti were now their own masters once more, and a ferocious species had been unleashed upon the rest of the universe.
Over the subsequent years, the Kzinti wreaked a most terrible revenge upon the conquered Jotoki; they used their newly-acquired technical knowledge with bio-engineering to devolve the Jotoki into semi-sentient slaves. Now they serve the Kzinti not just as workers, but also as food and sport. Many Jotoki run wild in "preserves" maintained for the favored Kzinti sport of hunting. They are a highly-valued prey, for they are still very cunning, and make for very entertaining and dangerous hunt.
Such is the fate of all who stand against the Kzinti. Sentient species taste better...