Freakin' awesome post!We're not the only race, even on Earth. Bottlenose dolphins, to cite just one example, are apparently fully sentient and have complex language capabilities - the only reason they lack technology is probably that they have limited anatomical ability to manipulate objects. Apes are also sentient, although their ability to communicate is more limited. There are more abstract arguments that organisms such as bees, ants, and cephalopods are intelligent, although this roams into more obscure domains of thinking that depend heavily on how flexible one's definitions are. I think they all have rights, but our ability to observe those rights is hampered by our own limitations as a species derived from evolutionary pressures. Nevertheless, in practice I tend toward Buddhist philosophy of universal benevolence toward life: I am a vegetarian, and will not kill bugs unless they are dangerous or invade in large numbers that might be a health hazard.
I find it unlikely we will ever run into alien intelligence. Not for lack of existence, mind you - I am virtually positive the universe is teeming with it, just as an extrapolation of the fact that the Earth is already swarming with it and it's only existed here for a few dozen millennia. But the timescales of evolution are so vast that, statistically speaking, species on the same technological level would be too far apart in space to have meaningful contact. If we ever did run into ETs, their civilization would be so old and large in scale that its actions would either look like natural phenomena or occur in regions so dense with activity we couldn't access them or discern what's going on - e.g., the interiors of stars, the plasma rings around black holes, etc. Nor would we run into archaeological relics, because space is simply too large and the timescales of relics that we could recognize would be relatively small.
And this mutual ignorance is probably a good thing: With few exceptions, the likelihood of contact with a civilization that found us comprehensible would be the destruction or subordination of one or the other. Even if both approached the relationship with benevolence, both are products of evolution and subject to behaviors that ultimately serve themselves at the expense of others.