Blog Post By: Aidan, Sea Turtle Intern
The life of a loggerhead sea turtle begins within an egg chamber hidden deep within the sand of nesting beaches. These nests can withstand storms, flooding, erosion, and human impacts and still prove successful. However, inundation, complete erosion, and predation of nests can result in an early end to the hatchlings lives. After a long incubation period, the embryos finally complete development and break through the eggshell using a specialized structure known as an egg tooth or caracal. This structure is shed shortly after its purpose has been fulfilled. Once outside the eggshell, hatchings can remain within the egg chamber for a few days to increase nutrient absorption from their egg yolk. This energy will be needed in the long journey that is yet to come.
On a cool, dark night, the action begins all at once. A decrease in sand temperature is used as an indicator of when the sun has set and if it is safe to emerge. Hatchings use each other to propel themselves upwards and out of the egg chamber. After peaking out of the sand to ensure the coast is clear, the dash to the ocean begins. In the utter darkness, the brightness of the ocean’s horizon is used as the main cue that tells hatchlings the correct direction to go. This was advantageous prior to the invention of artificial lights. Today, bright lights from houses, vehicles, or flashlights can misdirect hatchlings causing them to head in the opposite direction.
Even though heading to the sea during nighttime avoids the majority of predators, this does not mean hatchlings are in the clear. Nocturnal predators such as Racoons and Atlantic Ghost Crabs can pick off hatchlings on their scramble to the ocean. Hatchlings that fall behind can find themselves heading to the ocean during daylight. This exposes them to further diurnal predators such as Laughing Gulls, Crows, and Grackles. To these predators, hatchling season is a feast with an abundance of easy to catch food available to them.
One a hatchling has reached the ocean it swims against the direction of the waves to propel itself away from the shore. Out in the ocean, hatchlings are all alone and exposed to further marine predators including sharks, fish, and birds such as pelicans. This is why loggerhead hatchlings along the Atlantic coast of North America head directly away from coastal waters and into the open ocean. This area in the Central Atlantic Ocean is known as the Sargasso Sea. It is here where hatchlings will live the next stage of their life.
Sea Turtle Biologist