Sourced from Judy Goldman's Whiskers, Tails & Wings: Animal Folktales from Mexico, the story from the Seri people explains how the world was created, retold by Sofia Payne.
When the world was born, the god of creation, Hant Caai (ANT KYE) filled the world with water and populated it with all sorts of creatures. He realized in his haste he had forgotten to keep some dirt aside in order to make land above water. Due to the impossible depths of the ocean, Hant Caai called out to his marine creations for help.
The dolphin was confident he could get the job done and he dove off into the deep. However, he didn't get too far until he saw some tasty fish and so he became distracted and never completed his task.
The sea snail and the fish both tried to help Hant Caai collect dirt from the bottom of the ocean, but became frightened the deeper they swam, as the water grew darker and darker. They didn't want to be eaten and so they fled their mission.
Finally, it was Mosni who had the opportunity to help Hant Caai. Down she dove, farther and farther than the dolphin, the sea snail and the fish had gone. In fact, Mosni did not surface for many days and soon the others began to fear Mosni had been eaten or gotten lost.
When Mosni returned, while everyone was rejoicing on her behalf, she looked sad.
"Hant Caai, I'm sorry I could not return you more than this," and in her flipper were a few grains of sand. "Mosni, thanks to you, I can now make the land for this world. As your reward, you will be the first to walk upon it."
The modern leatherback turtle is a deep sea hunter, diving to depths up to 3,000 feet, lays its eggs on land and are capable of holding their breath for over 5 hours. The Seri people continue to honor and praise the leatherback turtle when they cross paths.