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Trees- ShrubsLeatherback Turtle (Demochelys coriacea)
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The leatherback, Demochelys coricea, is the world’s largest sea turtle with a carapace up to 270cm in length; its common name is derived from its uncharacteristic leathery skin found on its carapace (shell). The seven narrow ridges running the length of their carapace and the larger front flippers allow for easy identification of this species. D. coricea is the sole living representative of the family Dermochelyidae. The leatherback is dark in colour with both white and pink spots; the female also characteristically has a ‘pink spot’ on the top of their head (1).
Leatherbacks are exceptional amongst reptiles because they are able to partially control their internal body temperature using thermal inertia and specialised blood supply system in their shoulders (2). This allows the turtle to dive to depths of 4,200ft and stay down for as long as 85 minutes in search of prey (3).
They usually weight approximately 300 – 600 kg on average (4), although the largest recorded individual was a stranded male in 1988 which weighed 916kg (5). The life expectancy of the leatherback is 30 years or more (6).
Mature females will emerge on nesting beaches at night, coming high up the shore to deposit their eggs. The nesting beaches are sandy, tropical beaches with deep-water approaches, although some shallow-water beaches are also used in certain regions (7). To nest, females will use their rear flippers to excavate a hole into which approximately 100 eggs are laid, around 20% of this will be yolkless (4).
The gender of the hatchling is influenced by the temperature of incubation; cooler nests will produce all males and warmer nests will produce just females (8). Once hatched, the juveniles will remain in waters of at least 26°C until their carapace exceeds 100cm in curved length (6).
Sexual maturity is estimated by most authorities to be around 13-14 years, although this was established by skeletochronological analysis (9). So with a life expectancy of 30 years, it is taken as reasonable that an approximation for generation length would be 22 years (6).
The Leatherback turtle has a worldwide distribution. It is found from tropical to sub-polar oceans; nests on tropical (rarely subtropical) beaches (6).
These turtles will often undertake long-distance migrations between their feeding grounds, in temperate waters, to their nesting beaches in the tropics. This journey can exceed 7000km over several months (10).
Adult leatherbacks are truly pelagic, living almost their entire lives at sea. Very little is known about the life of leatherback turtles as after they leave the beach as a hatchling, they often never come onto dry land again. Most studies have been on mature females when they come ashore to lay their nest. Leatherbacks appear to migrate long distances between feeding and nesting areas, this was established with the use of satellite tracking.
The main diet for an adult leatherback turtle is jellyfish and planktonic tunicates. Turtles will often mistake plastic rubbish, bags in particular, for jellyfish and once ingested can cause death from starvation.
Critically endangered on the IUCN Redlist (6)
Listed under UK Biodiversity Action Plan
Addressed under a marine turtles Species Action Plan
Appendix I of the convention on the International Trade in Endangered Species of Flora and Fauna (CITES) 1975
Appendix II of the Bern Convention 1979
Appendices I and II of the Bonn Convention 1979
Annex IV of the EC Habitats Directive
Description written by Ben Harvey (2009)
(1) McDonald, D., Dutton, P.H., Bradner, R. & and Basford, S., 1996. Use of pineal spot (’pink spot’) photographs to identify leatherback turtles. Herpetological Review, (27), pp.11-12.
(2) Paladino, F., O’Connor, M. & and Spotila, J., 1990. Metabolism of leatherback turtles, gigantothermy, and thermoregulation of dinosaurs. Nature, (344), pp.858-60.
(3) Eckert, S., Eckert, K., Ponganis, P. & Kooyman, G., 1989. Diving and foraging behavior of leatherback sea turtles (Dermochelys coriacea). Canadian Journal of Zoology, (67), pp.2834-40.
(4) Fretey, J. & and Lescure, J., 1998. Les tortues marines en Guyane Francaise: bilan de vingt ans de recherche et de conservation. Revue d’Ethnobiologie, (40), pp.219-38.
(5) Eckert, K. & and Luginbuhl, C., 1988. Death of a giant. Marine Turtle Newsletter, (43), pp.2-3.
(6) Sarti Martinez, A.L., 2000. Dermochelys coriacea 2000 In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1.. Downloaded on 04 June 2009.
(7) Fretey, J., Dontaine, J. & and Neves, O., 1999. Sao Tome et Principe: zone de croissance pour les tortues-luths? Canopee, (0), pp.1-2.
(8) Rimblot, F. et al., 1985. Sexual differentiation as a function of the incubation temperature of eggs in the sea-turtle Dermochely coriacea (Vandelli, 1761). Amphibia-Reptilia, (6), pp.83-92.
(9) Zug, G. & and Parham, J., 1996. Age and growth in leatherback turtles, Dermochelys coriacea (Testudines: Dermochelyidae): A skeletochronological analysis. Chelonian Conservation and Biology, 2(2), pp.244-49.
(10) Hughes, G., Luschi, P. & Menacci, R.a.P.F., 1998. The 7000-km oceanic journey of a leatherback turtle tracked by satellite. Journal of Experimental Marine Biology and Ecology, (229), pp.209 – 217.
