From Brazil to Ascension Island without a GPS.

The Green Turtle is perhaps one of our greatest navigators, covering the 1400 miles from Brazil to Ascension to return to the beach it was hatched to lay her eggs. It is a journey that is without food as the ocean is to deep for the turtle to forage and when they arrive at Ascension there is very little in the way of food for them as they are vegetarians. The skills required to navigate this journey must be great indeed and to the best of my knowledge know one has yet been able to tell how they achieve this remarkable feat. Some have suggested they look up and see the stars and look down to see the ocean floor but the floor is many hundreds of feet away as they pass over the Brazil Basin and head to the Mid-Atlantic Ridge, to the west of which you will find Ascension, 7 degrees 55 minutes south of the equator.

Turtles, as I have said before, return to the place of their birth to mate and lay their eggs, although some females will have mated off the coast of Brazil, the males born at Ascension will normally return there to mate. It is not uncommon to see 3 or 4 males around a female as she is mating of shore and DNA tests have shown that the eggs in one nest are not always the product of one couple! Perhaps there will be as many as 120 eggs in the nest and the nest temperature determines the sex of the young. After incubation and hatching the first of the young makes its way to the surface of the sand and sticks a flipper into the air and if the temperature is low enough they assume it is night time and all head for the surface. Night time hatching means the young face less predators, especially Frigate birds, but if it is raining the temperature can feel right and they come out during the day and the Frigates and fish have a field day.

Hatching at night the young head for the brightest light, which is hopefully the moon shining on the water but it can be the lights of a house near the beach; when we lived on Ascension we often came home to a patio full of baby turtles that needed to be boxed up and taken down to the sea! It was always assumed that they needed to be released on the sand so that they could get the smell of the island, perhaps that’s how they find their way back without a GPS. Only about 1% survive the early years and return as adults about 25 years later to start the whole process over again.