Did Callie Dump "Stinky" for "Reindeer?"

Callie's long-time security object has been "Stinky" -- the remaining portion of which is the front end of a stuffed doggie. Callie has loved Stinky for almost all of her three years. Every evening, she would lie down before bedtime and "gum" Stinky, as if to "wind down" from a busy doggie day. It's been an amazing dog behavior to observe -- and the message is always, "OK, time to relax, everyone." Here's a photo, from the old days, of Callie with "Stinky." IMG_1742 (2) But the unthinkable seems to be happening: Callie seems to have dumped Stinky in favor of "Reindeer," a small stuffed toy reindeer with green antlers and a red scarf around his (her?) neck. We've been keeping track of Stinky for a few weeks, and Callie doesn't seem to have any interest any more. But she will roam all over the house looking for Reindeer. What is Callie thinking? I love to try to understand what's going on in a dog's mind. But this is pretty puzzling. For all these months, Callie was devoted to Stinky. And now all she cares about is Reindeer? What changed? How does a dog think about these things? Are we humans capable of figuring out dog behavior and the messages it sends? Sometimes. But, it seems, not always. How can I bond with my dog, if I can't figure it out?