" And then there was our Siamese cat, Sarah, who had been adopted as a kitten by our big tomcat, Diego, who would lick and clean her, let her knead his tummy as if she were nursing, and sleep with her. For about a decade they were best buddies, until Diego died of old age. Even though Sarah was younger and in perfect health, she stopped eating and died two months after Diego for no reason that the veterinarian could determine. "

― Frans de Waal , The Age of Empathy: Nature's Lessons for a Kinder Society