As one of seven species of sea turtle, the olive ridley sea turtle is a little on the smaller side in comparison to his cousins. They get their name from the greenish colouring of their shell, which starts out grey when they’re young but grows greener with age. These turtles thrive in the tropical waters of the Pacific and Indian Oceans. Once a year, thousands of olive ridley sea turtles gather together along the shores of Ostional, Costa Rica, for the arribada. This is when all the females nest and lay their eggs at the same time, usually within the same location where they hatched.