After laying the eggs the mother returns to the sea, and between 45 and 60 days later, depending on the temperature of the sand from the beach, the hatchlings emerge from the nest.
Hatchling cooperates with their siblings to emerge from the nest with synchronized movements, removing the sand from the chamber along their way up, a behavior termed as “social facilitation”, until they reach the surface of the nest. As a result they leave the nest all at once, reducing the risk of individual predation. Hatching usually occurs at night, guided by the changes in the sand temperature gradient; yet, this timing can also be related to protection against predators, since in most cases, the hatchlings have dark coloring, and during the day, become easy to spot on a white sandy beach.
The sand temperature is crucial to differentiate the sex of hatchlings. The so-called pivotal temperature, the incubating sand temperature which will lead to a 1:1 sex ratio in the nest, varies from species to species and among populations of the same species. Cooler temperatures produce males (usually below 28º C) and higher temperatures produce females (usually above 29º C ).
The hatchlings are small and fragile, measuring only about five centimeters. Many are eaten by crabs, sea birds, octopus and specially by fish. Others die of hunger and natural disease.
It is estimated that for every thousand born turtles, only one or two will reach adulthood.