Green Turtles use Earth’s magnetic field as GPS

Green Turtles are so called as the layer of fat under their shell (carapace) is green!

Green turtles and loggerhead turtles are super similar and can only be distinguished from each other by looking at their general body shape (greens are rounder with a flatter lateral profile and a much smoother shell) and the shape of the bill which is hooked in loggerheads.

Adult green turtles feed mainly on seaweed and seagrass and can often be seen close inshore, basking at the surface. They’ll also go to shore occasionally to bask in the sunshine.

What is most fascinating to us is that these turtles navigate using the Earth’s magnetic field. They can sense the field’s inclination, or the angle at which it dips towards the surface.

At the poles, this angle is roughly 90 degrees and at the equator, it’s roughly zero degrees. They can also sense its intensity, which is strongest near the poles and weakest near the Equator. Different parts of the world have unique combinations of these two variables. Neither corresponds directly to either latitude or longitude, but together, they provide a “magnetic signature” that tells the turtle where it is.

They are also the most widely distributed turtle, nesting in 80 countries. In the Southern Hemisphere, nesting occurs near Mozambique and other Indian Ocean Islands. Female green turtles can lay up to a whopping 150 eggs roughly every 12 days, totalling approximately 600 eggs per season. Sadly Turtles are seriously endangered due to fishing, pollution and global warming so we should all do our bit to support these enigmatic creatures.