costal scutes. Nesting females range from 58 to 78 cm in carapace length and have a relatively 

 large head, although smaller than that of the loggerhead turtle. 



Geographic variation in olive ridleys is subtle, and no subspecies are currently recognized. 

 However, the number of costal scutes apparently varies from one area to another, specimens with 

 only five pairs of costals being somewhat more abundant in the eastern Pacific than elsewhere. 

 In addition, overall carapace coloration is typically somewhat lighter in the western Atlantic than 

 in the eastern Pacific and the shell is typically more elevated in the eastern Pacific than 

 elsewhere. - . _ _ 



The most dramatic aspect of the life history of the olive ridley is the habit of forming great 

 nesting aggregations, generally known as "arribadas". Although not every adult olive ridley 

 participates in these arribadas, the vast majority of them do. Arribadas may be precipitated by 

 such climatic events as a strong offshore wind, or by certain phases of the moon and tide, but 

 there is a major element of unpredictability at all arribada sites. This unpredictability, and the 

 apparent ability of gravid females to wait for weeks while holding fully-shelled eggs, may be an 

 important aspect of the survival advantage of arribada-formation, a phenomenon usually 

 interpreted as one that evolved as a predator-saturation device. 



Individual olive ridleys may nest one, two or three times per season, typically producing 100-1 10 

 eggs on each occasion. The intemesting interval is variable, but for most localities it is 

 approximately 14 days for solitary nesters and 28 days for arribada nesters. 



The olive ridley occupies oceanic habitats and nests primarily on Pacific shores of the American 

 tropics and in the Guianas. in moderate numbers in tropical West Africa, and in relatively small 

 numbers elsewhere. Olive ridelys are extremely rare throughout Australia and Pacific oceanic 

 islands. 



Despite its local abundance, there are surprisingly few data relating to the feeding habits of the 

 olive ridley. However, those reports that do exist suggest that the diet in the western Atlantic and 

 eastern Pacific includes crabs, shrimp, rock lobsters, jellyfish, and tunicates. In some parts of the 

 world, it has been reported that the principal food is algae. 



SPECIES DISTRIBUTION 



The olive ridley is found in the tropical waters of the northern Indian, eastern Pacific and eastern 

 Atlantic Oceans. In the eastern Pacific nesting takes place from southern Sonora. Mexico, south 

 at least to Colombia. Non-nesting individuals occasionally are found in waters of the 

 southwestern United States. They occur abundantly in Pacific Colombia and Ecuador, but only 

 in small numbers in Peru and Chile. In Costa Rica, a major nesting aggregation is found at 

 Ostional. on the Nicoya Peninsula, and smaller arribadas occur at Nancite. in the Santa Rosa 

 National Park. Smaller arribadas also occur in Nicaragua at La Flor and Chacocente and at 

 several localities in Panama. 



The olive ridley has been recorded occasionally in Galapagos waters, but it is essentially very 

 rare throughout the islands of the Pacific. In the Indian Ocean it only achieves abundance in 

 eastern India and Sri Lanka, although minor nesting occurs alongside the green turtles at Hawke's 

 Bay, Pakistan, and some nesting also occurs in New Britain, Mozambique. Madagascar, 

 peninsular Malaysia, and various other localities. Four arribada sites have been reported in the 

 Indian State of Orissa, the most important being Gahirmatha Beach. 



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