@edgarblythe,
I have not the least doubt that what we call love is not just a human trait, but an animal trait. Both mammals and birds show strong attachments to humans, and to one another. Many species of bird mate for life. Dogs love humans and one another. A striking example came when our little girl dog died not quite a year ago. She and Mr. Bailey had often had their squabblers, and she had always dominated him. When she died, he seemed not to understand why she was "sleeping" in her dog bed on the end of the sofa (we left her there until The Girl could take her to the vet to be cremated). Then The Girl and one of her friends took Cleo out the front door, and, from Mr. Bailey's perspective, she never came back. (She came back in the form of ashes in an elegant little box.) Mr. Bailey began sleeping at the front door, waiting for his friend to come back--which of course, she never will. He sleeps there to this day, and in fact, when not outside to do his business, or going for a walk, he spends his day at the front door.
I've long thought that the assumptions that people make about animals--despising their intelligence or their equivalent of what we call humanity--is just species prejudice. Animals are, i believe, much more intelligent and perceptive than we give them credit for being. Even cats and dogs develop very close relationships. Love is not an exclusively human emotion.