So I’ve often heard other pet owners complaining that their pets will love a specific toy to death, no matter how old, dirty, and ragged it becomes. My friend’s cat, for example, will only play with one specific toy mouse. By now it’s falling apart, but whenever my friend tries to replace it with a new version of the same mouse, her cat refuses to play with it. Sadie has the opposite opinion about her toys. She loves getting a new toy, and usually plays with it excitedly for hours that first day. But once the toy is no longer new, Sadie loses interest in it. And by some method I don’t understand, Sadie can tell which toy is new and which is not, even if the toys are identical.