I like the imagery of the first few lines, though the import of the last few is a mystery to me. The Seri believed that the world started as an ocean. Haant-Caai tested the ability of the Giants by placing a man on a horse, off which he promptly fell. The Seri conclude from this that man was not meant to till the land and was meant to live off the sea. It is not known if they believe themselves descendents of the Giants, however, they occupy an important place in their folklore.
Turtles play an important part in the folk culture.