To dream that you are changing into the form of an animal indicates that you are becoming less civilized, less restrained and becoming more free and instinctive. You may be expressing your newfound freedom/independence and experiencing a lack of boundaries. Alternatively, taking the form of an animal suggests that your primal desires and/or repressed sexual urges are coming to the surface and needing to be satisfied. Consider also the animal that your turn into.
- Common Dreams