The actual documentation of the age of any species of sea turtle is difficult. What we do know is that sea turtles live a long time based on their species. Of the seven species of sea turtles on the globe, the hawksbill has the shortest lifespan at 30 to 50 years, and the green turtle has the longest at 80 years or more. The largest and smallest sea turtles–the leatherback and the kemp's ridley, respectively–both have an average lifespan of 45 to 50 years. The oldest sea turtle documented survived to be 150 years young! Most marine turtles take decades to mature—between 20 and 30 years—and remain actively reproductive for another 10 years.