If it's deeper, you may have a side to your personality that is animal, or feel that you're an animal inside some how, that you're not fully Human. Your animal self might be deep inside and hidden, or be with you in your every day life, where the animal is you, to where you relate to your world more as an animal than a Human.
Animal Transformation Mostly when a Human changes into an animal. Sometimes an animal changes into a Human, or one animal changes into another. There is a large fan-base for Human to animal transformations on the net, with plenty of stories and artwork to explore.
Weres "The animal inside" Weres often have the feeling of being another species than what they were born. Some Weres see their animal-self as an identity or an alter-ego, or it might be a spiritual connection to an animal you identify or feel close to. The other animal that a Were is, or identifies with, usually grows and changes through life, as you the Were grows and changes.
Morph, Morphs To change, usually the shape. You can morph into your animal form, take on your animal's looks, character, behavior. To be a morph, or morphic, is also a state of being, to be a mixed up combination of things, like animal, Human, male, female. The characters in Furry artwork can also be called morphs.
These are just the ideas of Boomer The Dog, based on my life, what I've learned from friends, and things I've read and experiences I've had being a Dog.