Description

The olive ridley is the smallest species of sea turtle and generally reaches a carapace length of only 27 inches and a weight of just over 100 lbs. They are lightly built with thin, slowly ossifying bones. The carapace is high-domed, generally possesses five costal scutes per side, and the margin is smooth. Olive ridleys are dark olive-green above yellowish below, a color that extends to the underside of the head and limbs as well. The head relatively large, but to a lesser degree than the loggerhead.

Distribution

The olive ridley is widespread in tropical seas. In the New World, its distribution is disjunct, occurring in the Pacific and in the western Atlantic from about the level of the Surinam south to the Tropic of Capricorn. Why olive ridleys do not enter the Caribbean remains a mystery. The closely-related and highly endangered Kemp’s ridley is restricted to the Gulf of Mexico.

Habitat & Ecology

Olive ridleys consume a variety of food including small shrimp, jellyfish, crabs, snails, fish, and in some populations algae is also eaten.

Reproduction

Ridley turtles are unique among marine turtles in their nesting behavior. Rather than arriving more or less individually, as with all other sea turtles, ridleys strand on their nesting beaches in large aggregations over a 3-4 day period. Very pronounced site fidelity occurs in this species. Ridleys can be observed congregating off shore in order to synchronize their nesting activity. Called an “arribada” (arrival) in Spanish, as many as 40,000 turtles may be found on the same small beach at the same time. There are so many turtles crowded together that later arrivals frequently dig up nests and eggs deposited by those that arrived earlier. Nesting is accomplished very quickly, usually within 45 min. This reproductive strategy saturates the predator population such that they cannot possibly consume all of the eggs deposited. Moreover, because ridleys nest only once per year, there is not enough resources to build up predator populations. In Panama, olive ridleys only nest on Pacific beaches and do so in late summer.
Like loggerheads, ridleys are reported to be ill tempered. When caught at sea, ridleys will attempt to bite and thrash violently if placed on their backs in boats. On nesting beaches, these turtles appear only slightly more irritable than other sea turtle species.

Conservation

Due to their strong nest-site fidelity, large numbers and predictable arrival, Ridleys have long been a favorite among harvesters of turtle eggs. As a consequence some populations have suffered severe depletions throughout their range. With regard to Kemp’s ridley, the single nesting population at Rancho Nuevo in the state of Tamaulipas, Mexico, has been nearly been exterminated and attempts to stimulate nesting on South Padre Island, Texas, may have come too late. In Panama, conservation programs operated by ANAM are ongoing at Isla de Cañas on the south end of the Azuero Peninsula.

Other Comments

None.

References

• Auth, D.L. 1994 Checklist and Bibliography of the Amphibians and Reptiles of Panama, Smithsonian Herptological Information Service. 98.
• Frank, N., & E. Ramus 1996 A Complete Guide to Scientific and Common Names of Reptiles and Amphibians of the World. NG Publishing, 337 pp.

Other Available References from the EMBL REPTILE DATABASE .

• Cogger (2000) Rept. Amph. of Australia, 6th ed.
• Cox etc. (1998) Phot. Guide Snakes Rept. Peninsular Malaysia, Singapore and Thailand.
• Duméril & Bibron. (1835) Erpétologie Générale, Rept., Vol. 2.
• Duméril & Bibron (1844) Erpetologie Générale, Vol.6.
• Ernst & Barbour (1989) Turtles of the World.
• ESCHSCHOLTZ (1829) Zool. Atlas, Pt. 1, p. 2, pl. 3
• Girard (1858) United States Exploring Expedition ..., U.S.N. Vol. 20. Herpetology.
• Glaw & Vences (1994) Fieldguide Amph and Rept. Madagascar.
• Gray (1844) British Museum (Natural History), London. viii + 80 p.
• Günther (1864) Rept. British India.
• Hay (1908) Proceedings of the United States National Museum 34 (1605): 183-198 + 6 plates
• Köhler (2000) Rept. Amph. Mittelamerikas, Bd 1.
• McCoy (2000) Rept. Solomon Islands. ZooGraphics, CD-ROM
• Rüppell (1835) S. Schmerber, Frankfurt a. M.
• Scott etc. (1983) In: Janzen, D.H. (ed.) Costa Rican Natural History. Univeristy of Chicago Press, pp. 351-
• Smith etc. (1979) Syn. Herpetofauna Mexico 6. Mexican Turtles, John Johnson, 1044 pp.
• Stebbins (1985) Field Guide Western Rept. and Amph., 2nd ed.
• Stejneger (1907) Bull. US. Natl. Mus., Washington, 58: xx, 1-577
• Strauch (1862) Mémoires de l'Académie Impériale des Sciences de St.-Pétersbourg, Série 7(5): 1-196
• Swash etc. (2001) Birds, Mammals, Reptiles Galapagos. Pica Press, 168 pp.
• Zug etc. (1994) Cat. Amer. Amph. Rept. 587 1994: 1-6
• Zug etc. (1998) Cat. Amer. Amph. Rept.. 653: 1-13.

Reference written by Dr. P. Lahanas, Institute for Tropical Ecology & Conservation Page last updated 14 May, 2003 Comments or Corrections: HerpsofPanamaITEC-edu.org Copyright © 1999-2003