NC EOG Practice Test 5

A Hatchling's First Trip

¹On a summer night on a North Carolina beach, a female loggerhead sea turtle drags herself out of the waves. Loggerheads can weigh more than 250 pounds, and on land they are slow and clumsy. She crawls up past the high-tide line, digs a hole with her back flippers, and lays about a hundred eggs, each about the size of a ping-pong ball. Then she covers the nest with sand and returns to the ocean. She will never see her babies.

²For about two months, the eggs incubate in the warm sand, slowly developing as the sun heats the beach above them. The temperature of the sand does something surprising: it helps decide whether the hatchlings will be male or female. Warmer nests produce more females, and cooler nests produce more males.

³When the hatchlings are ready, they break out of their shells and dig upward together, which can take several days. They usually wait just under the surface until the sand cools, a sign that night has come. Coming out in the dark protects them from the hot sun and from many of the birds that would eat them. Then, in a rush, dozens of hatchlings burst out of the sand at once.

⁴Each hatchling, no bigger than a cookie, has one goal: reach the water. But how does a turtle that has never seen the ocean know which way to go? Scientists have found that hatchlings crawl toward the brightest part of the horizon. On a natural beach, that is almost always the ocean side, where moonlight and starlight reflect off the water. The land side, with its tall dunes and plants, looks darker.

⁵This system worked for millions of years. Today, however, many beaches are lined with houses, hotels, and streetlights. To a hatchling, a porch light or a parking lot can look brighter than the sea. Confused hatchlings may crawl toward the lights instead of the water. By morning they can end up on roads or in yards, or worn out on dry sand, where the sun and hungry animals find them.

⁶Once a hatchling reaches the water, it swims hard for a day or more to get far from shore. Scientists believe young turtles then use other clues, such as the direction of the waves and Earth's magnetic field, to find their way across the open ocean.

⁷Many beach towns now help hatchlings by turning off or shielding lights that face the beach during nesting season. Volunteers watch over nests, and visitors are asked to fill in holes they dig and to use red flashlights, which bother turtles less, at night.

⁸These simple steps make a real difference. Even so, scientists estimate that only about one hatchling in a thousand lives long enough to become an adult. A female that does survive may return many years later to lay her own eggs on the same stretch of coast where she hatched.