100 million years and death
Last August I was in West Papua on what is thought to be one of the last beaches where Leatherbacks nest in the entire western Pacific (where Leatherbacks are even rarer and more endangered than in the eastern Pacific, the region of the 'race'). We watched females laying their eggs. It was one of the most extraordinary and wonderful things I have seen, and I will write about it some day.
As the Great Turtle Race people say, 'Leatherbacks are 100 million years old. They may only have 10 years left'.