Now that it's being filmed, I expect most of us have at least heard about Philip Pullman's "His Dark Materials" trilogy, with its alternate universe in which people have external souls called daemons which accompany them at all times, adopt the form of animals, and speak and act independently.
The daemons of children can change shape; but the daemons of those who have lost their innocence settle into a single animal, representative in some way of the character of the person. In the film, important people tend to have bigger, more powerful/independent/forceful animals as their daemons whereas more unassuming characters such as servants have smaller or less interesting daemons.
So - what would yours be?
I think mine would probably be a goat. Not because I smell, but because I am not a sheep. There would probably be lots of those in this universe...