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The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the luth, is the largest of all living
turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...
s and the heaviest non-
crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest livi ...
n reptile, reaching lengths of up to and weights of . It is the only living
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
in the genus ''Dermochelys'' and
family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Dermochelyidae Dermochelyidae is a family of turtles which has seven extinct genera and one extant genus, including the largest living sea turtles. Classification of known genera The following list of dermochelyid species was published by Hirayama and Tong i ...
. It can easily be differentiated from other modern
sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhe ...
s by its lack of a bony shell; instead, its
carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...
is covered by oily flesh and flexible,
leather Leather is a strong, flexible and durable material obtained from the tanning, or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle, sheep, goats, equine animals, buffalo, pigs and hog ...
-like skin, for which it is named.


Taxonomy and evolution


Taxonomy

''Dermochelys coriacea'' is the only
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
in genus ''Dermochelys''. The genus, in turn, contains the only extant member of the family
Dermochelyidae Dermochelyidae is a family of turtles which has seven extinct genera and one extant genus, including the largest living sea turtles. Classification of known genera The following list of dermochelyid species was published by Hirayama and Tong i ...
. Domenico Agostino Vandelli named the species first in 1761 as ''Testudo coriacea'' after an animal captured at Ostia and donated to the
University of Padua The University of Padua ( it, Università degli Studi di Padova, UNIPD) is an Italian university located in the city of Padua, region of Veneto, northern Italy. The University of Padua was founded in 1222 by a group of students and teachers from ...
by
Pope Clement XIII Pope Clement XIII ( la, Clemens XIII; it, Clemente XIII; 7 March 1693 – 2 February 1769), born Carlo della Torre di Rezzonico, was head of the Catholic Church and ruler of the Papal States from 6 July 1758 to his death in February 1769 ...
. In 1816, French
zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and d ...
Henri Blainville coined the term ''Dermochelys''. The leatherback was then reclassified as ''Dermochelys coriacea''. In 1843, the zoologist
Leopold Fitzinger Leopold Joseph Franz Johann Fitzinger (13 April 1802 – 20 September 1884) was an Austrian zoologist. Fitzinger was born in Vienna and studied botany at the University of Vienna under Nikolaus Joseph von Jacquin. He worked at the Vienna Natur ...
put the genus in its own family, Dermochelyidae. In 1884, the American naturalist
Samuel Garman Samuel Walton Garman (June 5, 1843 – September 30, 1927), or "Garmann" as he sometimes styled himself, was a natural history, naturalist/zoologist from Pennsylvania. He became noted as an ichthyologist and herpetologist. Biography Garman was ...
described the species as ''Sphargis coriacea schlegelii''. The two were then united in ''D. coriacea'', with each given subspecies status as ''D. c. coriacea'' and ''D. c. schlegelii''. The subspecies were later labeled invalid synonyms of ''D. coriacea''. Both the turtle's common and scientific names come from the leathery texture and appearance of its carapace (''Dermochelys coriacea'' literally translates to "Leathery Skin-turtle"). Older names include "leathery turtle" and "trunk turtle". The common names incorporating "lute" and "luth" compare the seven ridges that run the length of the animal's back to the seven strings on the musical instrument of the same name. But probably more accurately derived from the lute's ribbed back which is in the form of a shell.


Evolution

Relatives of modern leatherback turtles have existed in relatively the same form since the first true sea turtles evolved over 110 million years ago during the
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
period. The dermochelyids are relatives of the family
Cheloniidae Cheloniidae is a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. They are the only sea turtles t ...
, which contains the other six extant sea turtle species. However, their
sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...
is the extinct family
Protostegidae Protostegidae is a family of extinct marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, '' Archelon'', had a head long. Like most sea turtles, they had fl ...
that included other species that did not have a hard carapace.


Anatomy and physiology

Leatherback turtles have the most hydrodynamic body of any
sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhe ...
, with a large, teardrop-shaped body. A large pair of front flippers powers the turtles through the water. Like other sea turtles, the leatherback has flattened forelimbs adapted for swimming in the open ocean. Claws are absent from both pairs of flippers. The leatherback's flippers are the largest in proportion to its body among extant sea turtles. Leatherback's front flippers can grow up to in large specimens, the largest flippers (even in comparison to its body) of any sea turtle. The leatherback has several characteristics that distinguish it from other sea turtles. Its most notable feature is the lack of a bony
carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...
. Instead of
scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
s, it has thick, leathery skin with embedded minuscule
osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amp ...
s. Seven distinct ridges rise from the carapace, crossing from the cranial to caudal margin of the turtle's back. Leatherbacks are unique among
reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchocephalia ...
s in that their scales lack β-keratin. The entire turtle's
dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...
surface is colored dark grey to black, with a scattering of white blotches and spots. Demonstrating
countershading Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish ...
, the turtle's underside is lightly colored. Instead of teeth, the leatherback turtle has points on the
tomium In anatomy, the tomium is the sharp cutting edge of the beak of a bird or the bill of a turtle. Sometimes the edge is serrated for tearing through flesh or vegetation. See also * Culmen (bird) The beak, bill, or rostrum is an external anatomic ...
of its upper lip, with backwards spines in its throat (esophagus) to help it swallow food and to stop its prey from escaping once caught. ''D. coriacea'' adults average in curved carapace length (CCL), in total length, and in weight. In the
Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...
, the mean size of adults was reported at in weight and in CCL. Similarly, those nesting in
French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label= French Guianese Creole, Lagwiyann ) is an overseas department/region and single territorial collectivity of France on the northern Atlantic coast of South America in the Guianas ...
, weighed an average of and measured in CCL. The largest verified specimen ever found was discovered on the
Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
i beach of Sandspit and measured in CCL and in weight. A previous contender, the "Harlech turtle", was purportedly in CCL and in weight, however recent inspection of its remains housed at the
National Museum Cardiff National Museum Cardiff ( cy, Amgueddfa Genedlaethol Caerdydd) is a museum and art gallery in Cardiff, Wales. The museum is part of the wider network of Amgueddfa Cymru – National Museum Wales. Entry is kept free by a grant from the Welsh Gov ...
have found that its true CCL is closer to , casting doubt on the accuracy of the claimed weight, as well. On the other hand, one scientific paper has claimed that the species can weigh up to without providing more verifiable detail. The leatherback turtle is scarcely larger than any other sea turtle upon hatching, as they average in carapace length and weigh around when freshly hatched. ''D. coriacea'' exhibits several anatomical characteristics believed to be associated with a life in cold waters, including an extensive covering of
brown adipose tissue Brown adipose tissue (BAT) or brown fat makes up the adipose organ together with white adipose tissue (or white fat). Brown adipose tissue is found in almost all mammals. Classification of brown fat refers to two distinct cell populations with si ...
, temperature-independent swimming muscles, countercurrent heat exchangers between the large front flippers and the core body, and an extensive network of countercurrent heat exchangers surrounding the trachea.


Mechanical Properties

The carapace of the leatherback sea turtle has a unique design which enables the sea turtles to withstand high hydrostatic pressures as they dive to depths of 1200m. Unlike other sea turtles, the leatherback sea turtle has a soft, leathery skin which covers the osteoderms rather than a hard keratinous shell. The osteoderms are made up of bone-like hydroxyapatite/collagen tissue and have jagged edges, referred to as teeth. These osteoderms are connected by a configuration of interpenetrating extremities called sutures that provide flexibility to the carapace, enabling in plane and out of plane movement between osteoderms. This is important since the lungs, and thus the carapace, expand when taking in air and contract when deep diving. The sutures connect rigid elements and flexible joints in a zig-zag configuration, so there is no region where teeth can easily penetrate the carapace. There are two main failure mechanisms for the tires in tension: tooth failure corresponding to mineral-brittle failure; and interfacial failure between teeth corresponding to collagen-ductile failure. The triangular tooth geometry is able to evenly distribute load and absorb energy. This leads to a high strength in tension since this geometry takes advantage of the tensile strength of bone and the interface. Additionally, the carapace is tough because sutures prevent crack propagation.  Under load, cracks interact with the sutures which can resist crack growth via crack bridging. This phenomenon was observed in sequential compression of osteoderm samples.


Physiology

Leatherbacks have been viewed as unique among extant non-avian
reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchocephalia ...
s for their ability to maintain high body temperatures using metabolically generated heat, or
endotherm An endotherm (from Greek ἔνδον ''endon'' "within" and θέρμη ''thermē'' "heat") is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat released by its internal bodily functions inst ...
y. Initial studies on their metabolic rates found leatherbacks had resting metabolisms around three times higher than expected for reptiles of their size. However, recent studies using reptile representatives encompassing all the size ranges leatherbacks pass through during
ontogeny Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the s ...
discovered the resting metabolic rate of a large ''D. coriacea'' is not significantly different from predicted results based on
allometry Allometry is the study of the relationship of body size to shape, anatomy, physiology and finally behaviour, first outlined by Otto Snell in 1892, by D'Arcy Thompson in 1917 in '' On Growth and Form'' and by Julian Huxley in 1932. Overview Allom ...
. Rather than using a high resting metabolism, leatherbacks appear to take advantage of a high activity rate. Studies on wild ''D. coriacea'' discovered individuals may spend as little as 0.1% of the day resting. This constant swimming creates muscle-derived heat. Coupled with their countercurrent heat exchangers, insulating fat covering, and large size, leatherbacks are able to maintain high temperature differentials compared to the surrounding water. Adult leatherbacks have been found with core body temperatures that were above the water in which they were swimming. Leatherback turtles are one of the deepest-diving marine animals. Individuals have been recorded diving to depths as great as . Typical dive durations are between 3 and 8 minutes, with dives of 30–70 minutes occurring infrequently. They are also the fastest-moving non-avian reptiles. The 1992 edition of the ''
Guinness Book of World Records ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a reference book published annually, listing world ...
'' lists the leatherback turtle moving at in the water. More typically, they swim at .


Distribution

The leatherback turtle is a species with a
cosmopolitan Cosmopolitan may refer to: Food and drink * Cosmopolitan (cocktail), also known as a "Cosmo" History * Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953 Hotels and resorts * Cosmopoli ...
global range. Of all the extant sea turtle species, ''D. coriacea'' has the widest distribution, reaching as far north as
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...
and
Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of ...
and as far south as
Cape Agulhas Cape Agulhas (; pt, Cabo das Agulhas , "Cape of the Needles") is a rocky headland in Western Cape, South Africa. It is the geographic southern tip of the African continent and the beginning of the dividing line between the Atlantic and Indian ...
in Africa and the southernmost tip of
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
. The leatherback is found in all
tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
and
subtropical The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...
oceans, and its range extends well into the
Arctic Circle The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth. Its southern equivalent is the Antarctic Circle. The Arctic Circle marks the southernmost latitude at ...
. The three major, genetically distinct populations occur in the
Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
, eastern
Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
, and western Pacific Oceans. While nesting beaches have been identified in the region, leatherback populations in the Indian Ocean remain generally unassessed and unevaluated. Recent estimates of global nesting populations are that 26,000 to 43,000 females nest annually, which is a dramatic decline from the 115,000 estimated in 1980.


Atlantic subpopulation

The leatherback turtle population in the Atlantic Ocean ranges across the entire region. They range as far north as the
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...
and to the
Cape of Good Hope The Cape of Good Hope ( af, Kaap die Goeie Hoop ) ;''Kaap'' in isolation: pt, Cabo da Boa Esperança is a rocky headland on the Atlantic coast of the Cape Peninsula in South Africa. A common misconception is that the Cape of Good Hope is ...
in the south. Unlike other sea turtles, leatherback feeding areas are in colder waters, where an abundance of their
jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbre ...
prey is found, which broadens their range. However, only a few beaches on both sides of the Atlantic provide nesting sites. Off the Atlantic coast of Canada, leatherback turtles feed in the
Gulf of Saint Lawrence , image = Baie de la Tour.jpg , alt = , caption = Gulf of St. Lawrence from Anticosti National Park, Quebec , image_bathymetry = Golfe Saint-Laurent Depths fr.svg , alt_bathymetry = Bathymetry ...
near
Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirte ...
and as far north as
Newfoundland and Labrador Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...
. The most significant Atlantic nesting sites are in
Suriname Suriname (; srn, Sranankondre or ), officially the Republic of Suriname ( nl, Republiek Suriname , srn, Ripolik fu Sranan), is a country on the northeastern Atlantic coast of South America. It is bordered by the Atlantic Ocean to the nor ...
,
Guyana Guyana ( or ), officially the Cooperative Republic of Guyana, is a country on the northern mainland of South America. Guyana is an indigenous word which means "Land of Many Waters". The capital city is Georgetown. Guyana is bordered by the ...
,
French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label= French Guianese Creole, Lagwiyann ) is an overseas department/region and single territorial collectivity of France on the northern Atlantic coast of South America in the Guianas ...
in South America, Antigua and Barbuda, and
Trinidad and Tobago Trinidad and Tobago (, ), officially the Republic of Trinidad and Tobago, is the southernmost island country in the Caribbean. Consisting of the main islands Trinidad and Tobago, and numerous much smaller islands, it is situated south of ...
in the
Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...
, and
Gabon Gabon (; ; snq, Ngabu), officially the Gabonese Republic (french: République gabonaise), is a country on the west coast of Central Africa. Located on the equator, it is bordered by Equatorial Guinea to the northwest, Cameroon to the nort ...
in Central Africa. The beaches of
Mayumba National Park Mayumba National Park is a national park in southwestern Gabon. It is a thin tongue of beach, dunes, savanna, and rain-forest in the extreme south of the country, between Mayumba and the Congo border. Mayumba National Park shelters 60 km of ...
in
Mayumba, Gabon Mayumba is a Vili- and Shira-speaking town of about 5,208 people on the Atlantic Ocean coast of Gabon, at the end of the N6 road, lying on a peninsula separated from the mainland by the Banio Lagoon. Description It is known for its long sandy ...
, host the largest nesting population on the African continent and possibly worldwide, with nearly 30,000 turtles visiting its beaches each year between October and April. Off the northeastern coast of the South American continent, a few select beaches between French Guiana and Suriname are primary nesting sites of several species of sea turtles, the majority being leatherbacks. A few hundred nest annually on the eastern coast of
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...
. In Costa Rica, the beaches of Gandoca and
Parismina Barra del Parismina is a village of about 500 people located on the Caribbean coast of Costa Rica, at the mouth of the Reventazón River. Parismina is about halfway between Tortuguero and Limón on the Tortuguero canals. There is no road to Paris ...
provide nesting grounds.


Pacific subpopulation

Pacific leatherbacks divide into two populations. One population nests on beaches in Papua, Indonesia, and the Solomon Islands, and forages across the Pacific in the Northern Hemisphere, along the coasts of
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
,
Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
, and
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...
in North America. The eastern Pacific population forages in the Southern Hemisphere, in waters along the western coast of South America, nesting in Mexico, Panama, El Salvador, Nicaragua, and Costa Rica, as well as eastern Australia. The continental United States offers two major Pacific leatherback feeding areas. One well-studied area is just off the northwestern coast near the mouth of the
Columbia River The Columbia River ( Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia ...
. The other American area is located in California. Further north, off the Pacific coast of Canada, leatherbacks visit the beaches of
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...
. Estimates by the WWF suggest only 2,300 adult females of the Pacific leatherback remain, making it the most endangered marine turtle subpopulation.


South China Sea subpopulation

A third possible Pacific subpopulation has been proposed, those that nest in Malaysia. This subpopulation, however, has effectively been eradicated. The beach of
Rantau Abang Rantau Abang is a small village in Dungun District, Terengganu, Malaysia, which used to be known for its leatherback sea turtle nesting. It is located 22 km north of Kuala Dungun and 80 km south of Kuala Terengganu, Terengganu, Malaysia. ...
in Terengganu, Malaysia, once had the largest nesting population in the world, hosting 10,000 nests per year. The major cause of the decline was egg consumption by humans. Conservation efforts initiated in the 1960s were ineffective because they involved excavating and incubating eggs at artificial sites which inadvertently exposed the eggs to high temperatures. It only became known in the 1980s that sea turtles undergo
temperature-dependent sex determination Temperature-dependent sex determination (TSD) is a type of environmental sex determination in which the temperatures experienced during embryonic/larval development determine the sex of the offspring. It is only observed in reptiles and teleost fish ...
; it is suspected that nearly all the artificially incubated hatchlings were female. In 2008, two turtles nested at Rantau Abang, and unfortunately, the eggs were infertile. Additionally, there are small nesting sites in southern Thailand where 18 turtles nested in 2021.


Indian Ocean subpopulation

While little research has been done on ''Dermochelys'' populations in the Indian Ocean, nesting populations are known from Sri Lanka and the
Nicobar Islands The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean. They are located in Southeast Asia, northwest of Aceh on Sumatra, and separated from Thailand to the east by the Andaman Sea. Located southeast of the Indian ...
. These turtles are proposed to form a separate, genetically distinct Indian Ocean subpopulation.


Ecology and life history


Habitat

Leatherback sea turtles can be found primarily in the
open ocean The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...
. Scientists tracked a leatherback turtle that swam from Jen Womom beach of
Tambrauw Regency Tambrauw Regency is a regency of Southwest Papua Province, Indonesia. Geography Tambrauw Regency is a new regency located in Bird's head region of Papua Island. Geographically, Tambrauw. Regency is located at 132035' East Longitude (East Longitud ...
in West Papua of
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Gui ...
to the U.S. in a foraging journey over a period of 647 days. Leatherbacks follow their jellyfish prey throughout the day, resulting in turtles "preferring" deeper water in the daytime, and shallower water at night (when the jellyfish rise up the water column). This hunting strategy often places turtles in very frigid waters. One individual was found actively hunting in waters where temperatures were as low as . Following each foraging dive, the leatherback would return to warmer () surface waters to regain body heat before continuing to dive into near freezing waters. Leatherback turtles are known to pursue prey deeper than 1000 m—beyond the physiological limits of all other diving
tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct t ...
s except for
beaked whale Beaked whales ( systematic name Ziphiidae) are a family of cetaceans noted as being one of the least known groups of mammals because of their deep-sea habitat and apparent low abundance. Only three or four of the 24 species are reasonably well- ...
s and
sperm whales The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus ''Physeter'' and one of three extant species in the sperm whale fam ...
. Their favored breeding beaches are mainland sites facing the deep water, and they seem to avoid those sites protected by
coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
s.


Feeding

Adult ''D. coriacea'' turtles subsist almost entirely on jellyfish. Due to their
obligate {{wiktionary, obligate As an adjective, obligate means "by necessity" (antonym ''facultative'') and is used mainly in biology in phrases such as: * Obligate aerobe, an organism that cannot survive without oxygen * Obligate anaerobe, an organism tha ...
feeding nature, leatherbacks help
control Control may refer to: Basic meanings Economics and business * Control (management), an element of management * Control, an element of management accounting * Comptroller (or controller), a senior financial officer in an organization * Controlli ...
jellyfish populations. Leatherbacks also feed on other soft-bodied organisms, such as other
cnidarian Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that th ...
s (
siphonophore Siphonophorae (from Greek ''siphōn'' 'tube' + ''pherein'' 'to bear') is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 specie ...
s),https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Dermochelys_coriacea%20-%20Leatherback%20Turtle.pdf
tunicate A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one t ...
s ( salps and
pyrosoma Pyrosomes, genus ''Pyrosoma'', are free-floating colonial tunicates that usually live in the upper layers of the open ocean in warm seas, although some may be found at greater depths. Pyrosomes are cylindrical or cone-shaped colonies up to long, ...
s) and
cephalopod A cephalopod is any member of the molluscan class Cephalopoda ( Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s. They're also believed to feed on small
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapoda, decapods, ostracoda, seed shrimp, branchiopoda, branchiopods, argulidae, fish lice, krill, remipedes, isopoda, isopods, barnacles, copepods, ...
s,
fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...
(possibly symbiotes with jellies),
sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) o ...
s and
snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class ...
s. Pacific leatherbacks migrate about across the Pacific from their nesting sites in Indonesia to eat California jellyfish. One cause for their endangered state is plastic bags floating in the ocean. Pacific leatherback sea turtles mistake these plastic bags for jellyfish; an estimated one-third of adults have ingested plastic. Plastic enters the oceans along the west coast of urban areas, where leatherbacks forage, with Californians using upward of 19 billion plastic bags every year.Calrecycle.ca.gov
California Integrated Waste Management Board.
Several species of sea turtles commonly ingest plastic
marine debris Marine debris, also known as marine litter, is human-created waste that has deliberately or accidentally been released in a sea or ocean. Floating oceanic debris tends to accumulate at the center of gyres and on coastlines, frequently washing ...
, and even small quantities of debris can kill sea turtles by obstructing their digestive tracts. Nutrient dilution, which occurs when plastics displace food in the gut, affects the nutrient gain and consequently the growth of sea turtles. Ingestion of marine debris and slowed nutrient gain leads to increased time for sexual maturation that may affect future reproductive behaviors.Bjorndal, K.A. et al., 1997. Foraging Ecology and Nutrition of Sea Turtles. In The Biology of Sea Turtles by Peter L. Lutz and John A. Musick. 218-220. These turtles have the highest risk of encountering and ingesting plastic bags offshore of
San Francisco Bay San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland. San Francisco Bay drains water f ...
, the Columbia River mouth, and
Puget Sound Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected m ...
.


Lifespan

Very little is known of the species' lifespan. Some reports claim "30 years or more", while others state "50 years or more". Upper estimates exceed 100 years.


Death and decomposition

Dead leatherbacks that wash ashore are microecosystems while
decomposing Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is e ...
. In 1996, a drowned carcass held
sarcophagid Sarcophagidae () are a family of flies commonly known as flesh flies. They differ from most flies in that they are ovoviviparous, opportunistically depositing hatched or hatching maggots instead of eggs on carrion, dung, decaying material, or ...
and calliphorid flies after being picked open by a pair of ''
Coragyps atratus The black vulture (''Coragyps atratus''), also known as the American black vulture, Mexican vulture, zopilote, urubu, or gallinazo, is a bird in the New World vulture family whose range extends from the northeastern United States to Peru, Ce ...
'' vultures. Infestation by
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
-eating beetles of the families
Scarabaeidae The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...
,
Carabidae Ground beetles are a large, cosmopolitan family of beetles, the Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. As of 2015, it is one of the 10 most species-rich animal fami ...
, and
Tenebrionidae Darkling beetle is the common name for members of the beetle family Tenebrionidae. The number of species in the Tenebrionidae is estimated at more than 20,000 and the family is cosmopolitan in distribution. Taxonomy ''Tenebrio'' is the Latin gen ...
soon followed. After days of decomposition, beetles from the families
Histeridae Histeridae is a family of beetles commonly known as clown beetles or Hister beetles. This very diverse group of beetles contains 3,900 species found worldwide. They can be easily identified by their shortened elytra that leaves two of the seven ...
and
Staphylinidae The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra (wing covers) that typically leave more than half of their abdominal segments exposed. With roughly 63,000 species in thousands of genera, th ...
and anthomyiid flies invaded the corpse, as well. Organisms from more than a dozen families took part in consuming the carcass.


Life history


Predation

Leatherback turtles face many predators in their early lives. Eggs may be preyed on by a diversity of coastal predators, including
ghost crab Ghost crabs are semiterrestrial crabs of the subfamily Ocypodinae. They are common shore crabs in tropical and subtropical regions throughout the world, inhabiting deep burrows in the intertidal zone. They are generalist scavengers and predators ...
s,
monitor lizard Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are rec ...
s,
raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...
s,
coati Coatis, also known as coatimundis (), are members of the family Procyonidae in the genera ''Nasua'' and ''Nasuella''. They are diurnal mammals native to South America, Central America, Mexico, and the southwestern United States. The name ...
s, dogs,
coyote The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...
s, genets,
mongoose A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family is currently split into two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to so ...
s, and
shorebirds 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
ranging from small
plover Plovers ( , ) are a widely distributed group of wading birds belonging to the subfamily Charadriinae. Description There are about 66 species in the subfamily, most of them called "plover" or "dotterel". The closely related lapwing subf ...
s to large
gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century ...
s. Many of the same predators feed on baby turtles as they try to get to the ocean, as well as
frigatebird Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, ''Fregata''. All have predominantly black plumage, long, deeply forke ...
s and varied raptors. Once in the ocean, young leatherbacks face predation from
cephalopod A cephalopod is any member of the molluscan class Cephalopoda ( Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s, requiem sharks, and various large fish. Despite their lack of a hard shell, the huge adults face fewer serious predators, though they are occasionally overwhelmed and preyed on by very large marine predators such as
killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pat ...
s,
great white shark The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. It is nota ...
s, and
tiger shark The tiger shark (''Galeocerdo cuvier'') is a species of requiem shark and the last extant member of the family Galeocerdonidae. It is a large macropredator, capable of attaining a length over . Populations are found in many tropical and tempera ...
s. Nesting females have been preyed upon by
jaguar The jaguar (''Panthera onca'') is a large cat species and the only living member of the genus ''Panthera'' native to the Americas. With a body length of up to and a weight of up to , it is the largest cat species in the Americas and the th ...
s in the American tropics. The adult leatherback has been observed aggressively defending itself at sea from predators. A medium-sized adult was observed chasing a shark that had attempted to bite it and then turned its aggression and attacked the boat containing the humans observing the prior interaction. ''Dermochelys'' juveniles spend more of their time in tropical waters than do adults. Adults are prone to long-distance migration. Migration occurs between the cold waters where mature leatherbacks feed, to the tropical and subtropical beaches in the regions where they hatch. In the Atlantic, females tagged in French Guiana have been recaptured on the other side of the ocean in Morocco and Spain.


Mating

Mating In biology, mating is the pairing of either opposite- sex or hermaphroditic organisms for the purposes of sexual reproduction. ''Fertilization'' is the fusion of two gametes. ''Copulation'' is the union of the sex organs of two sexually reprod ...
takes place at sea. Males never leave the water once they enter it, unlike females, which nest on land. After encountering a female (which possibly exudes a
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
to signal her reproductive status), the male uses head movements, nuzzling, biting, or flipper movements to determine her receptiveness. Males can mate every year but the females mate every two to three years.
Fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Pro ...
is internal, and multiple males usually mate with a single female. This
polyandry Polyandry (; ) is a form of polygamy in which a woman takes two or more husbands at the same time. Polyandry is contrasted with polygyny, involving one male and two or more females. If a marriage involves a plural number of "husbands and wives" ...
does not provide the offspring with any special advantages. Female leatherbacks are known to nest up to 10 times in a single nesting season giving them the shortest internesting interval of all sea turtles.


Offspring

While other sea turtle species almost always return to their hatching beach, leatherbacks may choose another beach within the region. They choose beaches with soft sand because their softer shells and plastrons are easily damaged by hard rocks. Nesting beaches also have shallower approach angles from the sea. This is a vulnerability for the turtles because such beaches easily erode. They nest at night when the risk of predation and heat stress is lowest. As leatherback turtles spend the vast majority of their lives in the ocean, their eyes are not well adapted to night vision on land. The typical nesting environment includes a dark forested area adjacent to the beach. The contrast between this dark forest and the brighter, moonlit ocean provides directionality for the females. They nest towards the dark and then return to the ocean and the light. Females excavate a nest above the high-
tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...
line with their flippers. One female may lay as many as nine clutches in one breeding season. About nine days pass between nesting events. Average clutch size is around 110 eggs, 85% of which are viable. After laying, the female carefully back-fills the nest, disguising it from predators with a scattering of sand.


Development of offspring

Cleavage of the cell begins within hours of fertilization, but development is suspended during the
gastrulation Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells), or in mammals the blastocyst is reorganized into a multilayered structure known as the gastrula. ...
period of movements and infoldings of
embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
nic cells, while the eggs are being laid. Development then resumes, but embryos remain extremely susceptible to movement-induced mortality until the membranes fully develop after incubating for 20 to 25 days. The structural differentiation of body and organs (
organogenesis Organogenesis is the phase of embryonic development that starts at the end of gastrulation and continues until birth. During organogenesis, the three germ layers formed from gastrulation (the ectoderm, endoderm, and mesoderm) form the internal org ...
) soon follows. The eggs hatch in about 60 to 70 days. As with other reptiles, the nest's ambient temperature determines the sex of the hatchings. After nightfall, the hatchings dig to the surface and walk to the sea. The morphology of offspring has been found to vary with nest incubation temperatures. Higher temperatures resulted in lower mass, smaller appendages, narrower carapace widths, and shorter flipper lengths while lower temperatures resulted in greater mass, wider appendage widths, wider carapace widths, and longer flipper lengths. Leatherback nesting seasons vary by location; it occurs from February to July in
Parismina Barra del Parismina is a village of about 500 people located on the Caribbean coast of Costa Rica, at the mouth of the Reventazón River. Parismina is about halfway between Tortuguero and Limón on the Tortuguero canals. There is no road to Paris ...
, Costa Rica. Farther east in French Guiana, nesting is from March to August. Atlantic leatherbacks nest between February and July from South Carolina in the United States to the
United States Virgin Islands The United States Virgin Islands,. Also called the ''American Virgin Islands'' and the ''U.S. Virgin Islands''. officially the Virgin Islands of the United States, are a group of Caribbean islands and an unincorporated and organized territory ...
in the Caribbean and to Suriname and Guyana.


Importance to humans

People around the world still harvest sea turtle eggs. Asian exploitation of turtle nests has been cited as the most significant factor for the species' global population decline. In Southeast Asia, egg harvesting in countries such as Thailand and Malaysia has led to a near-total collapse of local nesting populations. In Malaysia, where the turtle is practically
locally extinct Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...
, the eggs are considered a delicacy. In the Caribbean, some cultures consider the eggs to be
aphrodisiac An aphrodisiac is a substance that increases sexual desire, sexual attraction, sexual pleasure, or sexual behavior. Substances range from a variety of plants, spices, foods, and synthetic chemicals. Natural aphrodisiacs like cannabis or cocai ...
s. They are also a major jellyfish predator, which helps keep populations in check. This bears importance to humans, as jellyfish diets consist largely of larval fish, the adults of which are commercially fished by humans.


Cultural significance

The turtle is known to be of cultural significance to tribes all over the world. The
Seri people The Seri or ''Comcaac'' are an indigenous group of the Mexican state of Sonora. The majority reside on the Seri communal property ( es, ejido), in the towns of Punta Chueca ( sei, Socaaix) and El Desemboque ( sei, Haxöl Iihom, link=no) on ...
, from the Mexican state of
Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the ...
, find the leatherback sea turtle culturally significant because it is one of their five main creators. The Seri people devote ceremonies and fiestas to the turtle when one is caught and then released back into the environment. The Seri people have noticed the drastic decline in turtle populations over the years and created a conservation movement to help this. The group, made up of both youth and elders from the tribe, is called Grupo Tortuguero Comaac. They use both
traditional ecological knowledge Traditional ecological knowledge (TEK) describes indigenous and other traditional knowledge of local resources. As a field of study in Northern American anthropology, TEK refers to "a cumulative body of knowledge, belief, and practice, evolving by ...
and Western technology to help manage the turtle populations and protect the turtle's natural environment. In the
Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federal constitutional monarchy consists of thirteen states and three federal territories, separated by the South China Sea into two regions: Peninsular Malaysia and Borneo's East Mal ...
n state of
Terengganu Terengganu (; Terengganu Malay: ''Tranung'', Jawi: ), formerly spelled Trengganu or Tringganu, is a sultanate and constitutive state of federal Malaysia. The state is also known by its Arabic honorific, ''Dāru l- Īmān'' ("Abode of Faith") ...
, the turtle is the state's main animal and is usually seen in tourism ads. On the South Island of New Zealand's
Banks Peninsula Banks Peninsula is a peninsula of volcanic origin on the east coast of the South Island of New Zealand. It has an area of approximately and encompasses two large harbours and many smaller bays and coves. The South Island's largest city, ...
the leatherback turtle has great spiritual significance to the Koukourārata
hapū In Māori and New Zealand English, a ' ("subtribe", or "clan") functions as "the basic political unit within Māori society". A Māori person can belong to or have links to many hapū. Historically, each hapū had its own chief and normally opera ...
of te Rūnanga o Ngāi Tahu, as well as wider significance in Te Ao Māori and to the peoples of greater
Polynesia Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...
according to the protocols of each
rohe The Māori people of New Zealand use the word ''rohe'' to describe the territory or boundaries of '' iwi'' (tribes), although some divide their rohe into several ''takiwā''. The areas shown on the map (right) are indicative only, and some iw ...
. In 2021, a leatherback sea turtle was laid to rest by New Zealand's Department of Conservation in a hilltop cave on the Peninsula's Horomaka Island dug by hapū and in accordance with their
rohe The Māori people of New Zealand use the word ''rohe'' to describe the territory or boundaries of '' iwi'' (tribes), although some divide their rohe into several ''takiwā''. The areas shown on the map (right) are indicative only, and some iw ...
's
ley lines Ley lines () are straight alignments drawn between various historic structures and prominent landmarks. The idea was developed in early 20th-century Europe, with ley line believers arguing that these alignments were recognised by ancient socie ...
, according to New Zealand's state broadcaster, Radio New Zealand.


Conservation

Leatherback turtles have few natural predators once they mature; they are most vulnerable to predation in their early life stages. Birds, small
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
s, and other opportunists dig up the nests of turtles and consume eggs.
Shorebirds 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
and
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapoda, decapods, ostracoda, seed shrimp, branchiopoda, branchiopods, argulidae, fish lice, krill, remipedes, isopoda, isopods, barnacles, copepods, ...
s prey on the hatchlings scrambling for the sea. Once they enter the water, they become prey to predatory fish and
cephalopod A cephalopod is any member of the molluscan class Cephalopoda ( Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s. Leatherbacks have slightly fewer human-related threats than other sea turtle species. Their flesh contains too much oil and fat to be considered palatable, reducing the demand. However, human activity still endangers leatherback turtles in direct and indirect ways. Directly, a few are caught for their meat by subsistence fisheries. Nests are raided by humans in places such as Southeast Asia. In the state of
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...
, there have been 603 leatherback strandings between 1980 and 2014. Almost one-quarter (23.5%) of leatherback strandings are due to vessel-strike injuries, which is the highest cause of strandings. Light pollution is a serious threat to sea turtle hatchlings which have a strong attraction to light. Human-generated light from streetlights and buildings causes hatchlings to become disoriented, crawling toward the light and away from the beach. Hatchlings are attracted to light because the lightest area on a natural beach is the horizon over the ocean, the darkest area is the dunes or forest. On Florida's Atlantic coast, some beaches with high turtle nesting density have lost thousands of hatchlings due to artificial light. Many human activities indirectly harm ''Dermochelys'' populations. As a pelagic species, ''D. coriacea'' is occasionally caught as
bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...
. Entanglement in lobster pot ropes is another hazard the animals face. As the largest living sea turtles,
turtle excluder device A turtle excluder device (TED) is a specialized device that allows a captured sea turtle to escape when caught in a fisherman's net. In particular, sea turtles can be caught when bottom trawling is used by the commercial shrimp fishing indu ...
s can be ineffective with mature adults. In the eastern Pacific alone, a reported average of 1,500 mature females were accidentally caught annually in the 1990s. Pollution, both chemical and physical, can also be fatal. Many turtles die from
malabsorption Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...
and intestinal blockage following the ingestion of balloons and plastic bags which resemble their jellyfish
prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
. Chemical pollution also has an adverse effect on ''Dermochelys''. A high level of
phthalate Phthalates (, ), or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften ...
s has been measured in their eggs'
yolks Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...
.


Global initiatives

''D. coriacea'' is listed on
CITES Appendix I CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of intern ...
, which makes export/import of this species (including parts) illegal. It has been listed as an EDGE species by the
Zoological Society of London The Zoological Society of London (ZSL) is a charity devoted to the worldwide conservation of animals and their habitats. It was founded in 1826. Since 1828, it has maintained the London Zoo, and since 1931 Whipsnade Park. History On 29 ...
. The species is listed in the
IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...
as VU ( Vulnerable), and additionally with the following infraspecific taxa assessments: * East
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...
subpopulation: CR ( Critically Endangered) * Northeast
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...
subpopulation: DD (
Data Deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...
) * Northwest
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
subpopulation: EN (
Endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...
) * Southeast Atlantic Ocean subpopulation: DD (Data Deficient) * Southwest Atlantic Ocean subpopulation CR (Critically Endangered) * Southwest Indian Ocean subpopulation CR (Critically Endangered) * West Pacific Ocean subpopulation CR (Critically Endangered) Conserving Pacific and Eastern Atlantic populations were included among the top-ten issues in turtle conservation in the first State of the World's Sea Turtles report published in 2006. The report noted significant declines in the Mexican, Costa Rican, and Malaysian populations. The eastern Atlantic nesting population was threatened by increased fishing pressures from eastern South American countries. The Leatherback Trust was founded specifically to conserve sea turtles, specifically its namesake. The foundation established a sanctuary in Costa Rica, the Parque Marino Las Baulas.


National and local initiatives

The leatherback sea turtle is subject to different conservation laws in various countries. The United States listed it as an
endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
on 2 June 1970. The passing of the
Endangered Species Act of 1973 The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...
ratified its status. In 2012, the National Oceanic and Atmospheric Administration designated 41,914 square miles of Pacific Ocean along California, Oregon, and Washington as "critical habitat". In Canada, the
Species at Risk Act The ''Species at Risk Act'' (SARA) (the ''Act'') is a piece of Canadian federal legislation which became law in Canada on December 12, 2002. It is designed to meet one of Canada's key commitments under the International Convention on Biological D ...
made it illegal to exploit the species in Canadian waters. The
Committee on the Status of Endangered Wildlife in Canada The Committee on the Status of Endangered Wildlife in Canada (COSEWIC, French: Comité sur la situation des espèces en péril au Canada, COSEPAC) is an independent committee of wildlife experts and scientists whose "raison d'être is to identify s ...
classified it as endangered. Ireland and Wales initiated a joint leatherback conservation effort between
Swansea University Swansea University ( cy, Prifysgol Abertawe) is a public university, public research university located in Swansea, Wales, United Kingdom. It was chartered as University College of Swansea in 1920, as the fourth college of the University of Wales. ...
and
University College Cork University College Cork – National University of Ireland, Cork (UCC) ( ga, Coláiste na hOllscoile Corcaigh) is a constituent university of the National University of Ireland, and located in Cork. The university was founded in 1845 as one o ...
. Funded by the
European Regional Development Fund The European Regional Development Fund (ERDF) is one of the European Structural and Investment Funds allocated by the European Union. Its purpose is to transfer money from richer regions (not countries), and invest it in the infrastructure and s ...
, the Irish Sea Leatherback Turtle Project focuses on research such as tagging and satellite tracking of individuals.
Earthwatch Institute Earthwatch Institute is an international environmental charity. Founded as Educational Expeditions International in 1971 by Bob Citron and Clarence Truesdale, Earthwatch supports hundreds of Ph.D. researchers across dozens of countries, conduct ...
, a global nonprofit that teams volunteer with scientists to conduct important environmental research, launched a program called "Trinidad's Leatherback Sea Turtles". This program strives to help save the world's largest turtle from extinction in Matura Beach, Trinidad, as volunteers work side by side with leading scientists and a local conservation group, Nature Seekers. This tropical island off the coast of Venezuela is known for its vibrant ethnic diversity and rich cultural events. It is also the site of one of the most important nesting beaches for endangered leatherback turtles, enormous reptiles that can weigh a ton and dive deeper than many whales. Each year, more than 2,000 female leatherbacks haul themselves onto Matura Beach to lay their eggs. With leatherback populations declining more quickly than any other large animal in modern history, each turtle is precious. On this research project, Dr. Dennis Sammy of Nature Seekers and Dr. Scott Eckert of Wider Caribbean Sea Turtle Conservation Network work alongside a team of volunteers to help prevent the extinction of leatherback sea turtles. Several Caribbean countries started conservation programs, such as the St. Kitts Sea Turtle Monitoring Network, focused on using
ecotourism Ecotourism is a form of tourism involving responsible travel (using sustainable transport) to natural areas, conserving the environment, and improving the well-being of the local people. Its purpose may be to educate the traveler, to provide fund ...
to highlight the leatherback's plight. On the Atlantic coast of Costa Rica, the village of
Parismina Barra del Parismina is a village of about 500 people located on the Caribbean coast of Costa Rica, at the mouth of the Reventazón River. Parismina is about halfway between Tortuguero and Limón on the Tortuguero canals. There is no road to Paris ...
has one such initiative. Parismina is an isolated sandbar where a large number of leatherbacks lay eggs, but poachers abound. Since 1998, the village has been assisting turtles with a hatchery program. The Parismina Social Club is a charitable organization backed by American tourists and expatriates, which collects donations to fund beach patrols. In
Dominica Dominica ( or ; Kalinago: ; french: Dominique; Dominican Creole French: ), officially the Commonwealth of Dominica, is an island country in the Caribbean. The capital, Roseau, is located on the western side of the island. It is geographical ...
, patrollers fro
DomSeTCo
protect leatherback nesting sites from poachers.
Mayumba National Park Mayumba National Park is a national park in southwestern Gabon. It is a thin tongue of beach, dunes, savanna, and rain-forest in the extreme south of the country, between Mayumba and the Congo border. Mayumba National Park shelters 60 km of ...
in Gabon, Central Africa, was created to protect Africa's most important nesting beach. More than 30,000 turtles nest on Mayumba's beaches between September and April each year. In mid-2007, the Malaysian Fisheries Department revealed a plan to clone leatherback turtles to replenish the country's rapidly declining population. Some conservation biologists, however, are skeptical of the proposed plan because cloning has only succeeded on mammals such as dogs, sheep, cats, and cattle, and uncertainties persist about cloned animals' health and lifespans. Leatherbacks used to nest in the thousands on Malaysian beaches, including those at
Terengganu Terengganu (; Terengganu Malay: ''Tranung'', Jawi: ), formerly spelled Trengganu or Tringganu, is a sultanate and constitutive state of federal Malaysia. The state is also known by its Arabic honorific, ''Dāru l- Īmān'' ("Abode of Faith") ...
, where more than 3,000 females nested in the late 1960s. The last official count of nesting leatherback females on that beach was recorded to be a mere two females in 1993. In Brazil, reproduction of the leatherback turtle is being assisted by the
Brazilian Institute of Environment and Renewable Natural Resources Brazilian Institute of the Environment and Renewable Natural Resources ( pt, Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis, IBAMA) is the Brazilian Ministry of the Environment's administrative arm. IBAMA supports anti- ...
' ''
projeto TAMAR The Projeto TAMAR (Portuguese for TAMAR Project, with TAMAR being an abbreviation of Tartarugas Marinhas, the Sea Turtles) is a Brazilian non-profit organization owned by the Chico Mendes Institute for Biodiversity Conservation. The main objecti ...
'' (TAMAR project), which works to protect nests and prevent accidental kills by fishing boats. The last official count of nesting leatherback females in Brazil yielded only seven females. In January 2010, one female at Pontal do Paraná laid hundreds of eggs. Since leatherback sea turtles had been reported to nest only at
Espírito Santo Espírito Santo (, , ; ) is a state in southeastern Brazil. Its capital is Vitória, and its largest city is Serra. With an extensive coastline, the state hosts some of the country's main ports, and its beaches are significant tourist attra ...
's shore, but never in the state of Paraná, this unusual act brought much attention to the area, biologists have been protecting the nests and checking their eggs' temperature, although it might be that none of the eggs are fertile. Australia's
Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...
lists ''D. coriacea'' as vulnerable, while Queensland's
Nature Conservation Act 1992 The ''Nature Conservation Act 1992'' is an act of the Parliament of Queensland, Australia, that, together with subordinate legislation, provides for the legislative protection of Queensland's threatened biota. As originally published, it pro ...
lists it as endangered.


See also

* Threats to sea turtles


References


External links


National Geographic


Further reading

* *The Leatherback Turtle: Biology and Conservation. United States, Johns Hopkins University Press, 2015. *Rake, Jody Sullivan. Leatherback Sea Turtles. United States, Capstone Press, 2012. *Hirsch, Rebecca E.. Leatherback Sea Turtles: Ancient Swimming Reptiles. United States, Lerner Publishing Group, 2015. {{Authority control Dermochelyidae Sea turtles Turtles of Africa Turtles of Asia Turtles of Europe Turtles of North America Reptiles of Oceania Turtles of South America Reptiles of Bangladesh Reptiles of Canada Reptiles of Myanmar Reptiles of Guatemala Reptiles of Guyana Reptiles of India Reptiles of Indonesia Reptiles of Japan Reptiles of Malaysia Reptiles of Mexico Reptiles of Pakistan Reptiles of West Africa Reptiles of the Solomon Islands Reptiles of Thailand Reptiles of Trinidad and Tobago Reptiles of the Dominican Republic Reptiles of the United States Fauna of Suriname Fauna of the Eastern United States Fauna of the Western United States Fauna of the San Francisco Bay Area Reptiles of Western Australia Articles containing video clips Reptiles described in 1761 Critically endangered fauna of Australia EPBC Act vulnerable biota Nature Conservation Act endangered biota Vulnerable biota of Africa Vulnerable fauna of Asia Vulnerable biota of Europe Vulnerable fauna of Oceania ESA endangered species Turtles of Australia Symbols of California