A green sea turtle's smooth, oval shell can grow up to 1.5 metres long. Despite their size, they are elegant swimmers, using their long front flippers like wings to 'fly' through the water. They can hold their breath for up to seven hours when resting on the seabed.
Every few years, female green sea turtles travel enormous distances across the ocean to return to the beach where they hatched, to lay their own eggs. Scientists think they find their way using Earth's magnetic field - a kind of built-in compass.
On Nauru, turtles are a respected part of the ocean world. Seeing one glide over the reef is a magical moment for islanders and visitors alike. Their calm, unhurried way of moving through the water is a reminder that the ocean has its own gentle rhythm.