Olive ridleys nest in large synchronised events known as arribadas – Spanish for arrival. Once, hundreds of thousands of olive ridley turtles would converge on beaches around the world to lay vast quantities of eggs. Now – due to egg poaching and industrial fishing – arribadas events happen on only a handful of beaches in Central America and India. Despite evidence that olive ridleys are the most populous of sea turtles and that some local populations are rising, population sizes around the world have been greatly reduced and olive ridleys still face the possibility of extinction.

Scientific Name
Lepidochelys olivacea

Conservation status
Olive ridley turtles are classified as Endangered by the International Union for Conservation of Nature (IUCN)

Description
Olive ridley turtles are named for their olive-grey carapace (top of shell); their light colour allows them to nest during the day by reflecting heat. They are relatively small turtles with a round shape. The carapace is domed from the front and heart shaped. The plastron (under part of shell) is cream. Adult carapace length averages 0.7 metre.

Hatchlings have a black carapace and light brown plastron.

Distribution
Olive ridley turtles occur in tropical and subtropical regions of the Pacific Ocean (though in fewer numbers in the western Pacific) and the Indian Ocean (though less on the eastern side). They are also found on either side of the southern Atlantic.

Habitat
Olive ridleys are normally found in coastal waters although they have been seen in open waters where currents cause floating seaweed and other material to converge.

Lifecycle
The olive ridley strategy of synchronised mass hatching events means predators are swarmed with overwhelming numbers of hatchlings, ensuring plenty of hatchlings make it off the beach and out to open water. Little is known of their early years, though based on the kemps ridley turtle it is thought that they reach sexual maturity in 11 to 16 years. Adults appear to wander the oceans, navigating by reading subtle clues such as changes in water temperature. They have large quantities of magnetite in their brains that likely enables them to navigate by read the earth’s magnetic field.

Diet
Adult olive ridleys are omnivorous (feeds on plants and animals) and feed on a wide variety of sea life including fish, crabs, snails, jellyfish algae.

Nesting
Olive ridleys nest together in spectacular displays known as arribadas – Spanish for arrival – during which thousands come ashore to nest together over a period of a few days. Today olive ridley arribadas are only witnessed on a handful of beaches along the Pacific Central American coast including Mexico and in eastern India. Past arribadas in Suriname and the South Andaman that involved hundreds of thousands of animals no longer take place. Solitary nesting also takes place on beaches in 32 countries around the world.

Olive ridleys are unique amongst sea turtles for nesting during the day. Special adaptations prevent them from over heating, the reason other turtle species mainly nest at night.