If you are dreaming of a dead or dying animal, it represents the end of something important to you.
If the animal is your pet, it suggests you are disappointed with the world and see no hope in it.
If it is a dead person in your dream, it represents a thought you have ignored.
If the person comes back to life, then your thought is attempting to come to the surface.
However, if you admit grieving over the events in the dream, you are ready to move on from the thought that is haunting you.