Costa Rica’s Incredible Olive Ridley Sea Turtle Arribada

She waited 500 yards offshore in the warm, tropical eastern Pacific ocean off Ostional Beach. Just fifteen the olive ridley sea turtle was in a small country that Christopher Columbus had discovered and named “Costa Rica”, the “rich coast” five centuries earlier.

The moon was in its last quarter. The afternoon November rains had passed as she waited expectantly, unaware of the lunar effect bringing her near.

A few yards away, another olive ridley sea turtle joined her, then a third, followed by a dozen, then hundreds, thousands, now tens of thousands. For countless years the moon has passed its timeless phases that affect this planet—and that, for more than one hundred million years has drawn marine turtles back to their ancestral homes.

Nature is forever mysterious. Just a few months earlier, this turtle was foraging in the middle of the Pacific Ocean more than 2,500 miles away. And the hundreds of thousands now alongside her were scattered over more than a million square miles of ocean.

Though food was plentiful far out in the Pacific, something was stirring inside her. She and hundreds of thousands like her felt the same inexorable pull to return to Costa Rica. They had to go back to where they had arrived.

Now, as she waited in the soft moonlight, she was ready. Over the thousands of miles she had swum she had been bred by several different males in the clear tropical waters because, somehow, they, too, were being affected by something unseen, a force primeval. It was something so compelling that it had been bringing her race back to the same Costa Rica beach since the days of dinosaurs.

In the tropical night this little sea turtle was waiting. She had somehow found to the very beach where she had hatched in 1995. We do not know how a Pacific marine turtle finds the exact beach where she started life. There are only a few nesting beaches on earth and they are not very big. In fact Ostional Beach is only a few hundred meters long. Now part of Costa Rica’s Ostional National Wildlife Refuge, it is almost certainly the most important olive ridley marine turtle nesting site in the world. Incredibly, in 1995, the year this turtle hatched, perhaps as many as 500,000 female olive pacific sea turtles had nested here in huge waves. These massive invasions are called “arribadas.”

Unfortunately, our sea turtle’s mother will not nest at Ostional this year. For the last two decades, her mother had joined massive Costa Rica arribadas several times every year and she would have done so again except that she drowned in a shrimping net not fitted with an internationally required turtle escape device. Long-line fishermen killed thousands more in what is politely called “incidental catch” almost completely avoidable simply by using larger fishing hooks. Untold thousands died unnecessarily by eating plastic bags.

Of course, the tens of thousands of olive ridleys just offshore know none of this. As we look out over the water in the pale moonlight, there are now so many that it almost seems one could walk on their backs for a mile or more. We stand in awe at the sheer numbers of God’s creation. They don’t know or comprehend that they were on earth long before the first Tyrannosaurus Rex. They don’t know that we are waiting for them to come ashore so that when they lay their eggs on this tiny wildlife refuge, men, women, and children will lawfully raid their nests and take 1,000,000 eggs in return for protecting the rest of the clutches and preserving the species. They only know that this is where they are meant to be.

Then, though no one knows why, it happens. As quietly as they first appeared, as silently as they gathered, their patience has been rewarded and they begin to come ashore. A single olive ridley turtle followed by a second. Then there are hundreds, thousands, tens of thousands—even more than that—each intent on one task: bringing new life. All night they come. And all day, day after day. It is a wonder of magnificent Costa Rica and as timeless as the phases of the moon. It is the spectacular display of life called Arribada.