Somewhere around a child’s fourth birthday, the whine begins. At first it’s a soft sound, the gentle “aww” whenever anyone walks by with a puppy or friendly dog, and the begging grows with every cat video that pops up on any website. It hits a fever pitch when someone—a neighbor, a relative—gets a puppy or a kitty or a goldfish. Soon, you give in and get a pet. Thank goodness there are some new picture books that are almost as lovable as your new responsibility.