I have a Westie that is 1 1/2 years old. She is "fixed" and is generally a very happy, sweet little dog. She has a favorite toy -- a little stuffed bunny. She plays with all of her toys, but this bunny is her favorite. When it gets later in the evening, she runs around the house with the bunny in her mouth crying, all the while her tail is wagging like she's the happiest dog in the world. She really cries a lot, too, but she is visibly not upset at all, in fact she's the opposite. Very happily prancing around, crying, with her bunny. Any ideas on why she does this? She's done it all her life.