I have to believe that somewhere in the parameter space of human diplomacy and relationships there is the possibility for expansion and coexistence without utter annihilation of one side. We appear to be doing it on some scales in the modern age, certainly much better than we've done before, though not perfectly.<p>Still, homo sapiens largely wiped out neanderthal populations many eons ago. They had a similar to larger cranial capacity to cro-magnons and modern humans, they used and created tools, and there's some evidence of cultural artifacts such as jewelry around their sites. The signs point to a culture of intelligent humanoids, now almost completely wiped out (except with possible genetic relics in the human population). This genocide preceded civilization as we know it by millennia...<p>Placental mammals, crossing over to south america from the isthmus of Panama when it arose, almost completely destroyed marsupials in south america. That's not just an ethnicity, race, or species, it's an entire infraclass. It is likely the case that <i>our</i> primate ancestors did the same for many other classes of beings.<p>So to turn the clock back, it is hard to know when to stop. Fundamentally it is difficult for me to reason about when it is good for one creature to profit while others perish. I do know, though, that they are in a much more complicated relationship -- that it is impossible to separate one creature from its ecosystem, and that if no particular creature or plant or species is to be sacred above others, then surely it's the integrity and continued vitality of the ecosystem that matters. This is one reason I am an environmentalist: human beings now have immense power over the environment, and as such need to take responsibility for the fact that they can alter it, destroy it, or care for it. We have to become not the Earth's ignorant children, but the it's gardeners.