This question already has an answer here:
I don't have a great deal of info on what I'm looking for. I read a book when I was younger, probably written in the 80’s or early 90’s.
It was about these 2 people (male I think) that were traveling across a land to get somewhere, they would have to become the creatures that inhabited that area to get across it. They were deer once, beaver, one was a pixie once, there were other creatures.