I reviewed the book, Gramma Nancy's Animal Hats (and Booties, Too) by Nancy Nielsen.
I made one of the hats for my daughter, who is 9, and it did fit a little snuggly. I will go up a size next time I make them. The other knock on the book is that some pieces were to be hot glued and stuffed with styrofoam, which was not attractive or safe for a child. I know that the directions were written that way so that all skill levels of knit/crochet can do the embellishments, but I would have liked to have seen instructions for knit/crochet embellishments, or at least something that would have been safer for a child/baby (considering that this is the dynamic the book is marketed for).
Overall, the book is worth a look at the local library, if not as an addition to your library for it's reusability and cuteness.