For humans, and many mammals, having babies is just the beginning of the job. Raising the babies comes next, and humans reasonably expect at least 18 years of parenting — helping children learn to navigate the world and hopefully to learn independence. For many reptiles, including sea turtles, once the eggs are laid, and appropriately covered, the job is done. Mother sea turtles leave babies to fend for themselves, and to find their way on some of the longest migrations needed for survival. This is nature at its most primal and stunning; how can baby sea turtles find their way to migrate as much as 8000 miles (12,874.75km) when they’re just been born?
An interesting study on Loggerhead turtles in the 1990s suggests that baby sea turtles may be able to sense magnetic fields of the earth, helping to guide them toward the Atlantic and back in this 8000 mile swim that Loggerheads take yearly. There’s also suggestion that some turtles may be born without this sense, because not all turtles make it. If they slip into colder waters they get lost and become ready prey for other marine animals.
Many do survive and are said to be born with an internal compass, knowing instinctively from magnetic fields exactly where to go. Similar studies have been performed on leatherback turtles. These show that the baby sea turtles are intensely sensitive to magnetic energy, allowing them not only to make their first migration, but also usually to return to the beach on which they were born, called the natal beach.
Another study on baby sea turtles, especially the green turtles of Hawaii, who have an 800-mile (1287.48km) yearly migration, evaluates how the turtles find their way from nest to ocean. They appear to be guided by light, and the babies in concert, after digging themselves out of the nest, make way for the brightest horizon. Artificial lights on beaches can mean quick death for these intrepid survivors; those baby turtles born on beaches with artificial lights have very little chance of survival.
Baby sea turtles are not the only animals that can sense some aspect of earth that humans can’t. Butterflies can see ultraviolet light, and rattlesnakes can see or sense infrared wavelengths, both part of the electromagnetic spectrum. On earth, magnetic fields change and shift, and apparently sea turtles are in most cases sensitive to these changes, keeping them in warmer and safer waters and guiding their way. You really have to appreciate this natural ability as a wonderful example of the adaptive powers of the animal kingdom. Through it baby sea turtles survive, thrive and make unimaginably long journeys, which begin just a few days after birth.
