In one of the short films being shown at the Ghibli Museum, the one which shows the evolution from amoeba to boy, there is a subtle and haunting riddle at the core of it.
As I mentioned in my post on Ghibli, much of the film focuses on the competition between the creatures that will become the boy with another creature – the protagonist is a fish that jumps to land and grows legs in order to avoid the jaws of a bigger fish with sharp teeth. But soon afterwards, as the protagonist crawls freely away, he finds himself being trailed by another amphibian, which is presumably the fish that tried to eat him earlier. This other, larger amphibian now acts as his rival, jumping on him to move ahead in their race. The protagonist then mounts up on two legs to run past him (in a gesture that is peculiarly Asian: the arms are raised quite high while running, and the new creature looks over both cautiously and contemptuously at his rival as he runs by). Then, the two become dinosaurs – the protagonist eventually becomes a triceratops being chased by a giant Tyrannosaur. At the next stage, the protagonist becomes a rodent, while the Tyrannosaur transforms into a bird and sweeps far above the lowly mammal. We don’t see the rival as the hero evolves into ape, caveman, and then boy. But when he reaches the top of a mountain, there is a girl waiting for them, and they kiss.
Now, the question is, where did the girl come from? Was she the boy’s nemesis from earlier on, during primeval times? Is she what became of the bird? Not an unlikely interpretation, given the flying girls who populate Miyazaki’s imagination: Nausicaa, Kiki, and Sheeta. Indeed, there’s something quite mischievously clever about the giant predator and graceful bird evolving into the focus of the boy’s desire. But the best part of all is that this possibility is left unstated by the film.