Amazing mystery of baby green turtle navigation ability

Picture of a baby green-sea-turtle reaching the ocean.

Amazing navigational ability


Although we know little about what happens to the baby green turtles after their entering the water, we can be pretty sure that they do not get lost.

According to naturalists, they have a homing and navigational ability that rivals that of pigeons, bees and salmon.

Female turtles have been tagged on beaches and in a little more than a year have shown up about 1,400 miles away.

Nevertheless, studies have proved that they will always return to the same beach to lay their eggs, perhaps a couple hundred yards (183 meters) from where they themselves were hatched.

For example, according to A Natural History of Sea Turtles, no turtle tagged at Tortuguero (Costa Rica) has ever been found nesting at another place.

How does the turtle manage to find its way back to this beach after having traveled thousands of miles in the ocean?

Many theories have been proposed, but so far no satisfactory answer has been forthcoming.

Consider some of the possible answers to this marvelous mystery.

A native legend says that the turtles are guided by Cerro Tortuguero.

That is a mount of volcanic rock at the northern end of the nesting beach.

It is five hundred feet (152 meters) high and covered with tropical vegetation.

But sea turtles cannot see well above water, and many turtles return to parts of the twenty-mile (32-kilometer) nesting beach that are out of sight of the mountain.

Another theory is that green turtles use celestial navigation, orienting themselves by observing the stars.

Celestial position-finding would require a fantastically complicated map sense.

Yet, their poor eyesight when their heads are out of the water presents a problem as to this possible explanation.

A professor of zoology who has studied  green turtles for many years speculates that the turtles “smell” their way back to the same beach. Imagine that!

But how?

Is there something about the chemical characteristics of the sand or groundwater in this area that the turtles can recognize?

Then how do they guide themselves back and forth over the years to ocean “pasture grounds” many hundreds of miles away?

This specialist on green turtles concludes:

We really have made very little progress in accounting for either the long-range navigation of turtles, or their ability to recognize their hatching place.”