Sea turtles are ancient marine reptiles that spend almost their entire lives in the ocean, navigating vast distances across the world’s seas. These reptiles maintain a unique connection to land, as they must return for a specific and critical life event. While their streamlined bodies are perfectly adapted for aquatic life, their occasional presence on sandy shores is a display of their biological imperatives.
The Primary Reason: Nesting
Female sea turtles come ashore primarily for nesting. This behavior is a fundamental aspect of their life cycle, as sea turtle eggs require incubation in a terrestrial environment. Eggs laid underwater would suffocate due to a lack of oxygen and be highly vulnerable to aquatic predators. This evolutionary adaptation ensures the survival and development of their offspring, allowing embryos to breathe through a membrane in the eggs.
Timing and Conditions for Nesting
Sea turtle nesting seasons vary depending on the species and geographic location, generally occurring during warmer months. In the U.S., for example, nesting typically spans from March through October, with peak activity often observed between May and August. Most species of sea turtles primarily come ashore at night. This nocturnal timing helps them avoid the heat of the day, which can cause exhaustion and dehydration, and offers some protection from predators.
Female turtles seek out specific environmental conditions for their nests, preferring sandy beaches above the high tide line. These locations provide moist sand suitable for incubation and reduce the risk of nests being washed away by tides. Individual turtles may nest multiple times within a single season, laying anywhere from two to eight clutches of eggs, with intervals of about 10 to 15 days between each nesting event. Females often return to nest every two to four years, typically to their natal beach.
The Nesting Process
Once a female sea turtle emerges from the ocean and selects a suitable spot, the nesting process begins. She first uses her front flippers to create a shallow depression, known as a “body pit.” She then employs her rear flippers to dig a narrower, flask-shaped egg chamber, often up to a meter. The turtle deposits her eggs, typically between 50 and 200 soft-shelled eggs, depending on the species.
After laying the eggs, the female covers the egg chamber with sand using her hind flippers. She then engages in a “sand-throwing” behavior, scattering sand over a wide area with her front flippers. This action, once thought to be primarily for camouflage, is now believed to create “decoy” nests, confusing predators and obscuring the exact location of the real nest by disrupting visual and olfactory cues. The entire process can take one to three hours, after which the female returns to the sea.
Responsible Observation
Observing a nesting sea turtle requires adherence to guidelines to ensure the safety and success of the nesting event. It is important to maintain a significant distance, typically 10 to 30 feet, and remain quiet and still to avoid disturbing the turtle. Sudden movements or loud noises can cause a nesting female to abandon her attempt and return to the ocean without laying her eggs.
Artificial lights, including flashlights, phone lights, and camera flashes, can disorient both nesting females and emerging hatchlings, leading them away from the ocean. If light is necessary, a red-filtered light is less disruptive. Do not touch the turtle or its eggs, as physical contact can stress the animal and interfere with its natural behavior. Filling in holes, knocking down sandcastles, and removing beach equipment before dark help ensure a clear path for turtles. Reporting any disturbances or injured turtles to local wildlife authorities is helpful.