Olive, the Other Reindeer by J.Otto Seibold
From Chronicle Books:
Olive is merrily preparing for Christmas when suddenly she realizes "Olive... the other Reindeer... I thought I was a dog. Hmmm, I must be a Reindeer!" So she quickly hops aboard the polar express and heads to the North Pole. And while Santa and the other reindeer are a bit surprised that a dog wants to join the their team, in the end Olive and her unusual reindeer skills are just what Santa and his veteran reindeer team need. Colorful graphic illustrations accompany this zany dog story from the well-known author and artist team, Vivian and J.Otto Seibold. Adorable Olive and her hilarious adventures are sure to make anyone's Christmas merry.