I was talking on the phone with an old friend about my little pet mouse， Prudence. She had recently died， and I missed her terribly. Not everyone could understand how the world had grown gray for me when I lost my rodent3 companion， how hard it was to come home at the end of the day to my empty New York City apartment where no one， not even a mouse， stirred4. But I knew I could turn to my friend， a scientist Who worked with lab animals. She listened to me grieve