The big journey

When it is not nesting season, sea turtles may migrate hundreds or even thousands of miles. In the open ocean, sea turtles encounter strong currents; they have only modest vision; they can only raise their heads several inches out of the water; and there are often no visible landmarks. Even with these limitations, sea turtles regularly navigate long distances to find the same tiny stretch of nesting beach. How they do it is one of the greatest mysteries in the animal kingdom, and finding an answer has been the focus of generations of researchers. One promising new theory on how sea turtles navigate suggests that they can detect both the angle and intensity of the earth's magnetic field. Using these two characteristics, a sea turtle may be able to determine its latitude and longitude, enabling it to navigate virtually anywhere. Early experiments seem to prove that sea turtles have the ability to detect magnetic fields.