" The tug-of-war we secretly feel between our animal and human natures is part of what makes us endearingly compassionate, and mighty strange primates. Unlike other animals, we care deeply about scores of life forms with whom we share the planet, even though they're not family members, not even species members, for that matter, not possessions and not personal friends. We care abstractly about whole populations we may not have seen firsthand, determined to help fellow creatures survive. We feel a powerfully mingled kinship. "

― Diane Ackerman , The Human Age: The World Shaped By Us