The Cat Who Walked by Herself (1988)

Two parents put their child in his crib for the night and leave the room. The child starts crying, and the Cat comes into the room to keep him company. The child grabs her tail, and the Cat angrily reminds him that they agreed a thousand years ago that he would not do that. Upon seeing that the child doesn't remember, the Cat sighs and decides to tell him the story from the beginning. The story starts when the planet was young and life on Earth is starting with dinosaurs.