Here's a disturbing thought, nicely put:
In the penultimate chapter of her book, Kolbert tackles that question by examining one particularly troubling extinction. The Neanderthals were extremely similar to us; less than 0.3 percent of our DNA diverges. But they did not venture into new terrain, they did not significantly alter the terrain they were already in, and they certainly did not make a bonsai project out of the tree of life. They had, in Kolbert’s words, “no more impact on their surroundings than any other large vertebrate.”
Meanwhile, we Homo sapiens traveled out of Africa en route to everywhere, encountered the Neanderthals in Europe, had sex with them, and, directly or through competition for resources, exterminated them. Some 30,000 years later, we rediscovered them, via their remains, in a cave in limestone cliffs in a valley in Germany. That cave no longer exists. Those cliffs no longer exist. We quarried the limestone, smelted it with coke and iron ore, and converted it to steel.
What species does this? Only ours. Somewhere along the line, thanks to some twist in that 0.3 percent of uniquely human DNA, we became the sort of creatures who could level cliffs and turn stone to steel; “the sort of creature,” Kolbert writes, “who could wipe out its nearest relative, then dig up its bones and reassemble its genome.”
from review by Kathryn Shulz of "The Sixth Extinction", by Elizabeth Kolbert
Makes you proud, doesn't it?