Hundreds of female turtles gather in coastal waters and come simultaneously on a shore in a spectacular mass-nesting event called arribada ('arrival by the sea' in Spanish). Scientists cannot explain how these ladies communicate to get ashore all together, but this mystery is to be witnessed. Two major arribada sites in Costa Rica are Playa Ostional and Playa Nancite, on the Pacific shore. The nesting lasts around ten days, taking place in different months, peaking in September–October.
After two months, tiny baby turtles less than 4 cm long start getting out of the nests.
Practical info
What is the arribada nesting strategy of olive ridley turtles?
Olive ridley turtles have a unique nesting strategy called arribada. During this mass-nesting event, hundreds of female turtles arrive together on the shore to lay eggs after gathering in the coastal waters. The phenomenon fascinates scientists, who are yet to understand how these turtles communicate and synchronize their egg-laying process. Arribada is popular among tourists worldwide who come to experience the breathtaking sight. Show more
How do female turtles communicate to come ashore simultaneously during arribada?
Despite various theories, scientists remain uncertain about the communication method of female olive ridley turtles to coordinate their egg-laying process during arribada. Researchers suggest the usage of ocean currents, Earth's magnetic field, lunar cycles, and the togetherness of all of these for synchronization. However, no sure-shot answer is available yet. Nevertheless, the mass nesting of olive ridley turtles is an alluring sight to behold. Show more
What are the two major arribada sites in Costa Rica?
Costa Rica houses two significant arribada sites, Playa Ostional and Playa Nancite, on its Pacific shore. Playa Ostional at the Ostional National Wildlife Refuge has the maximum number of nesting female olive ridley turtles in the world. Santa Rosa National Park's Playa Nancite, comparatively quieter and more reserved than Playa Ostional, also allows visitors to experience the yearly arribada event. Show more
When is the nesting season of olive ridley turtles in Costa Rica?
The nesting season for olive ridley turtles in Costa Rica starts in August and ends in November, with September and October being the peak months. The timing of the event, however, depends on a variety of factors like ocean currents, lunar cycles, and weather conditions, which differ every year, making it necessary to consult national park officials or local guides to plan a trip around the event. Show more
How long after nesting do baby olive ridley turtles start to hatch from eggs?
Once the olive ridley female turtles lay eggs in the sand, it takes the hatchlings roughly 45-55 days to develop and hatch. The baby turtles are less than 4 cm long and weigh only a few grams. These young turtles overcome numerous challenges such as predators, artificial lights, and poachers to reach the ocean. While few turtles reach adulthood, those that do continue the cycle by returning to the same beach to nest in future years. Show more
