I am Not a Dog!

The other night before bed I was reading the book Dinosaur Hunt to my 2 year old.  It's about a dog that is hunting for a dinosaur.  The first page of the book, seen below, shows the dog stating that he is NOT a dog.

My 2 year old was not happy when I read this page.  She kept saying, "Daddy!  That is a dog!  Daddy!  That's a dog!"  She wasn't getting the meaning of the book and I didn't have a good way of explaining it to her.  How do you explain to a 2 year old what the words "I am not a dog" mean when they are next to what is clearly a dog?!?!?!