Dalyan is a neighbourhood of the municipality and district of Ortaca , Muğla Province , Turkey . Its population is 5,829 (2022). Before the 2013 reorganisation , it was a town ( belde ). It is located between Marmaris and Fethiye on the south-west coast of Turkey .
115-414: Dalyan achieved international fame in 1987 when developers wanted to build a luxury hotel on the nearby İztuzu Beach , a breeding ground for the endangered loggerhead sea turtle species. The incident created major international storm when David Bellamy championed the cause of conservationists such as June Haimoff , Peter Günther, Nergis Yazgan, Lily Venizelos and Keith Corbett. The development project
230-609: A common meal; locals claim the egg is an aphrodisiac . Eating turtle eggs or meat can cause serious illness due to harmful bacteria, such as Pseudomonas aeruginosa and Serratia marcescens , and high levels of toxic metals that build up through bioaccumulation . The US West Coast is a critical migratory corridor for the Pacific loggerheads, in which these turtles swim across the Pacific to California's coast from breeding grounds in Japan. Important foraging habitats for juveniles in
345-433: A complete bony plastron and an incomplete carapace. The fossil showed that the plastron evolved before the carapace. Like crown turtles, it lacked intercostal muscles, so rib mobility was limited. The ribs were laterally expanded and broadened without ossification, like the embryos of modern turtles. The development of a shell reaches completion with the late Triassic Proganochelys of Germany and Thailand. It lacked
460-521: A fully developed carapace and a relocated rib cage. The theory accounted for the evolution of fossil pareisaurs from Bradysaurus to Anthodon , but not for how the ribs could have become attached to the bony dermal plates. Recent stem-turtle fossil discoveries provide a "comprehensive scenario" of the evolution of the turtle's shell. A fossil that may be a stem-turtle from the Permian of South Africa, Eunotosaurus , some 260 million years ago, had
575-515: A greater list of known prey than any other sea turtle. Other food items include sponges , corals , sea pens , polychaete worms , tube worms , sea anemones , cephalopods , barnacles , brachiopods , amphipods , isopods , Portuguese men o' war , insects, bryozoans , hydrozoans , sea urchins , sand dollars , sea cucumbers , starfish , tunicates , fish (eggs, juveniles, and adults), hatchling turtles (including members of its own species), algae, and vascular plants . During migration through
690-467: A lifespan of 47–67 years. The loggerhead sea turtle is omnivorous , feeding mainly on bottom-dwelling invertebrates . Its large and powerful jaws serve as an effective tool for dismantling its prey. Young loggerheads are exploited by numerous predators; the eggs are especially vulnerable to terrestrial organisms. Once the turtles reach adulthood, their formidable size limits predation to large marine animals, such as large sharks. The loggerhead sea turtle
805-444: A short broad trunk, and a body-case of broadened and somewhat overlapping ribs, suggesting an early stage in the acquisition of a shell. The fossil has been called "a diapsid reptile in the process of becoming secondarily anapsid". Olivier Rieppel summarizes the phylogenetic origins of the ancestral turtles: " Eunotosaurus is placed at the bottom of the stem section of the turtle tree, followed by Pappochelys and Odontochelys along
920-472: A single polymorphic species. Molecular genetics has confirmed hybridization of the loggerhead sea turtle with the Kemp's ridley sea turtle , hawksbill sea turtle , and green sea turtles . The extent of natural hybridization is not yet determined; however, second-generation hybrids have been reported, suggesting some hybrids are fertile. Although evidence is lacking, modern sea turtles probably descended from
1035-480: A single common ancestor during the Cretaceous period. Like all other sea turtles except the leatherback, loggerheads are members of the ancient family Cheloniidae , and appeared about 40 million years ago. Of the six species of living Cheloniidae, loggerheads are more closely related to the Kemp's ridley sea turtle , olive ridley sea turtle , and the hawksbill turtle than they are to the flatback turtle and
1150-422: A single undivided gular scute. The gular scutes may be referred to as a gular projection if they stick out like a trowel . The plastral formula is used to compare the sizes of the individual plastral scutes (measured along the midseam). The following plastral scutes are often distinguished (with their abbreviation): Comparison of the plastral formulas provides distinction between the two species. For example, for
1265-431: A thinning of eggshells, tissue damage, or deviation from natural behaviors. Artificial lighting discourages nesting and interferes with the hatchlings' ability to navigate to the water's edge. Females prefer nesting on beaches free of artificial lighting. On developed beaches, nests are often clustered around tall buildings, perhaps because they block out the man-made light sources. Loggerhead hatchlings are drawn toward
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#17327729492121380-510: A wide array of this floating debris, including bags, sheets, pellets, balloons and abandoned fishing line. Loggerheads may mistake the floating plastic for jellyfish, a common food item. The ingested plastic causes numerous health concerns, including intestinal blockage, reduced nutrient absorption and malnutrition, suffocation, ulcerations, or starvation. Ingested plastics release toxic compounds, including polychlorinated biphenyls , which may accumulate in internal tissues. Such toxins may lead to
1495-644: Is Oman , on the Arabian Peninsula, which hosts around 15,000 nests, giving it the second largest nesting population of loggerheads in the world. Western Australia is another notable nesting area, with 1,000–2,000 nests per year. Pacific loggerheads live in temperate to tropical regions. They forage in the East China Sea , the southwestern Pacific, and along the Baja California Peninsula . Eastern Australia and Japan are
1610-419: Is 545 kg (1,202 lb) and the maximum (presumed total) length is 213 cm (84 in). The head and carapace (upper shell) range from a yellow-orange to a reddish brown, while the plastron (underside) is typically pale yellow. The turtle's neck and sides are brown on the tops and yellow on the sides and bottom. The turtle's shell is divided into two sections: carapace and plastron. The carapace
1725-598: Is a highly fertile and productive agricultural zone. Cotton used to be grown intensively, but has now largely been replaced by pomegranate. In the area around Köyceğiz many other fruits (citrus fruits) and vegetables are grown, which are all on display in the market on Saturdays, the day when villagers come from miles around to sell their products. Above the river's sheer cliffs are the weathered façades of Lycian tombs cut from rock, circa 400 BC ( 36°50′1.09″N 28°38′3.16″E / 36.8336361°N 28.6342111°E / 36.8336361; 28.6342111 ). The ruins of
1840-455: Is apparent in both sections of the shell, carapace, and plastron, and is thicker in critical areas. A thicker epidermis allows a higher stress force to be experienced without permanent deformation or critical failure of the shell. The shape of the shell is from its evolutionary process, which caused many microstructures to appear to aid survival and motion. Shell shape allows the animal to escape predatory situations. Microstructures can include
1955-571: Is considered a vulnerable species by the International Union for Conservation of Nature . In total, nine distinct population segments are under the protection of the Endangered Species Act of 1973 , with four population segments classified as "threatened" and five classified as "endangered". Commercial international trade of loggerheads or derived products is prohibited by CITES Appendix I . Untended fishing gear
2070-567: Is currently unknown. In February 2015, a live loggerhead turtle was found floating in British Columbian waters of 10.5 °C (50.9 °F) with extensive algal growth on its carapace. Female-female aggression, which is fairly rare in other marine vertebrates , is common among loggerheads. Ritualized aggression escalates from passive threat displays to combat. This conflict primarily occurs over access to feeding grounds. Escalation typically follows four steps. First, initial contact
2185-632: Is further divided into large plates, or scutes . Typically, 11 or 12 pairs of marginal scutes rim the carapace. Five vertebral scutes run down the carapace's midline, while five pairs of costal scutes border them. The nuchal scute is located at the base of the head. The carapace connects to the plastron by three pairs of inframarginal scutes forming the bridge of the shell. The plastron features paired gular , humeral, pectoral, abdominal, femoral, and anal scutes. The shell serves as external armor, although loggerhead sea turtles cannot retract their heads or flippers into their shells. Sexual dimorphism of
2300-464: Is high in Caretta caretta tears. The skull is most easily distinguished from other sea turtles by having maxillae that meet in the mid-line of the palate. The portion of skull behind the eyes is also relatively large and bulbous due to the extensive jaw muscles. The loggerhead sea turtle has a cosmopolitan distribution , nesting over the broadest geographical range of any sea turtle. It inhabits
2415-606: Is mating-induced. Through the act of mating, the female ovulates eggs which are fertilized by the male. This is unique, as mating-induced ovulation is rare outside of mammals. In the Northern Hemisphere, loggerheads mate from late March to early June. The nesting season is short, between May and August in the Northern Hemisphere and between October and March in the Southern Hemisphere. Loggerheads may display multiple paternity . Multiple paternity
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#17327729492122530-595: Is not available, the other suffices. The turtles swim at about 1.6 km/h (0.9 kn; 0.4 m/s) during migration. Like all marine turtles, the loggerhead prepares for reproduction in its foraging area. This takes place several years before the loggerhead migrates to a mating area. Female loggerheads first reproduce at ages 28–33 in Southeastern United States and Australia, and at ages 17–30 in South Africa. Age at first reproduction in
2645-679: Is possible due to sperm storage. The female can store sperm from multiple males in her oviducts until ovulation. A single clutch may have as many as seven fathers, each contributing sperm to a portion of the clutch. Multiple paternity and female size are positively correlated . Two hypotheses explain this correlation. One posits that males favor large females because of their perceived higher fecundity (ability to reproduce). The other states, because larger females are able to swim more quickly to mating grounds, they have longer mating periods. All sea turtles have similar basic nesting behaviors. Females return to lay eggs at intervals of 12–17 days during
2760-456: Is responsible for many loggerhead deaths. The greatest threat is loss of nesting habitat due to coastal development, predation of nests, and human disturbances (such as coastal lighting and housing developments) that cause disorientations during the emergence of hatchlings. Turtles may also suffocate if they are trapped in fishing trawls . Turtle excluder devices have been implemented in efforts to reduce mortality by providing an escape route for
2875-452: Is stimulated by visual or tactile cues. Second, confrontation occurs, beginning with passive confrontations characterized by wide head-tail circling. They begin aggressive confrontation when one turtle ceases to circle and directly faces the other. Third, sparring occurs with turtles snapping at each other's jaws. The final stage, separation, is either mutual, with both turtles swimming away in opposite directions, or involves chasing one out of
2990-528: Is the turtles' primary threat in the North Pacific. They also become stuck in traps, pots, trawls , and dredges . Caught in this unattended equipment, loggerheads risk serious injury or drowning. Turtle excluder devices for nets and other traps reduce the number being accidentally caught. Nearly 11 million metric tons of plastic are released into the ocean annually. A number that is projected to increase to 29 million metric tons by 2040. Turtles ingest
3105-540: Is the world's largest hard-shelled turtle, slightly larger at average and maximum mature weights than the green sea turtle and the Galapagos tortoise . It is also the world's second largest extant turtle after the leatherback sea turtle . Adults have an approximate weight range of 80 to 200 kg (180 to 440 lb), averaging around 135 kg (298 lb), and a straight-line carapace length range of 70 to 95 cm (28 to 37 in). The maximum reported weight
3220-848: The Adriatic Sea , with tens of thousands of specimens (mainly sub-adult) seasonally present in the North-Eastern portion of the latter, above all in the area of the Po Delta . Greece is the most popular nesting site along the Mediterranean, with more than 3,000 nests per year. Zakynthos hosts the largest Mediterranean nesting with the second one being in Kyparissia Bay. Because of this, Greek authorities do not allow planes to take off or land at night in Zakynthos due to
3335-557: The Atlantic , Pacific , and Indian Oceans , as well as the Mediterranean Sea . It spends most of its life in saltwater and estuarine habitats, with females briefly coming ashore to lay eggs. The loggerhead sea turtle has a low reproductive rate; females lay an average of four egg clutches and then become quiescent , producing no eggs for two to three years. The loggerhead reaches sexual maturity within 17–33 years and has
3450-912: The Cape Verde Islands . The Cape Verde Islands are the only significant nesting site on the eastern side of the Atlantic. Loggerheads found in the Atlantic Ocean feed from Canada to Brazil. In the Indian Ocean, loggerheads feed along the coastlines of Africa, the Arabian Peninsula , and in the Arabian Sea . Along the African coastline, loggerheads nest from Mozambique 's Bazaruto Archipelago to South Africa's St Lucia estuary. The largest Indian Ocean nesting site
3565-821: The Red foxes in Australia , Jackals and feral dogs , procyonids , Feral cats , Feral pigs , and humans . During their migration from their nests to the sea, hatchlings are preyed on by dipteran larvae, crabs, toads, lizards, snakes, seabirds such as frigatebirds , and other assorted birds and mammals. In the ocean, predators of the loggerhead juveniles include portunid crabs and various fishes, such as parrotfishes and moray eels . Adults are more rarely attacked due to their large size, but may be preyed on by large sharks, seals, and killer whales. Nesting females are attacked by flesh flies, feral dogs, and humans. Salt marsh mosquitos can also pester nesting females. In Australia,
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3680-514: The Sargassum habitat with a variety of other organisms. The mats of Sargassum contain as many as 100 different species of animals on which the juveniles feed. Prey found in Sargassum mats may include barnacles, crab larvae , fish eggs, and hydrozoan colonies. Some prey, such as ants, flies, aphids , leafhoppers , and beetles, are carried by the wind to the mats. Marine mammals and commercial fishes, including tuna and mahi-mahi, also inhabit
3795-423: The Sargassum mats. Loggerhead sea turtles observed in captivity and in the wild are most active during the day. In captivity, the loggerheads' daily activities are divided between swimming and resting on the bottom. While resting, they spread their forelimbs to about midstroke swimming position. They remain motionless with eyes open or half-shut and are easily alerted during this state. At night, captives sleep in
3910-495: The eastern box turtle , the plastral formula is: an > abd > gul > pect > hum >< fem. Turtle plastrons were used by the ancient Chinese in a type of divination called plastromancy . See also Oracle bones . The turtle's shell is covered in scutes that are made of keratin . The individual scutes as shown above have specific names and are generally consistent across the various species of turtles. Terrestrial tortoises do not shed their scutes. New scutes grow by
4025-613: The green turtle . Around three million years ago, during the Pliocene epoch, Central America emerged from the sea, effectively cutting off currents between the Atlantic and Indo-Pacific Oceans. The rerouting of ocean currents led to climatic changes as the Earth entered a glacial cycle. Cold water upwelling around the Cape of Good Hope and reduction in water temperature at Cape Horn formed coldwater barriers to migrating turtles. The result
4140-408: The hawksbill turtle , among other species, has been used as a material for a wide range of small decorative and practical items since antiquity, but is normally referred to as tortoiseshell . The turtle shell is made up of numerous bony elements, generally named after similar bones in other vertebrates, and a series of keratinous scutes which are also uniquely named. The ventral surface is called
4255-424: The osteoid , and the periosteum . The evolution of the plastron has remained more mysterious, though Georges Cuvier, a French naturalist and zoologist in the 19th century, wrote that the plastron developed primarily from the sternum of the turtle. This fits well with the knowledge obtained through embryological studies, showing that changes in the pathways of rib development often result in malformation or loss of
4370-473: The plastron . These are joined by an area called the bridge. The actual suture between the bridge and the plastron is called the anterior bridge strut. In Pleurodires the posterior pelvis is also part of the carapace, fully fused with it. This is not the case in Cryptodires which have a floating pelvis. The anterior bridge strut and posterior bridge strut are part of the plastron. On the carapace are
4485-496: The respiratory tract . More than 100 species of animals from 13 phyla , as well as 37 kinds of algae, live on loggerheads' backs. These parasitic organisms, which increase drag, offer no known benefit to the turtle, although the dulling effect of organisms on shell color may improve camouflage . In 2018, researchers from Florida State University examined 24 individual turtle carapaces and found an average of 33,000 meiofauna with one turtle having 150,000 organisms living on
4600-459: The 14,500 km (9,000 mi) trip from Mexico across the Pacific. Adelita was the first animal of any kind ever tracked across an ocean basin. The Mediterranean Sea is a nursery for juveniles, as well as a common place for adults in the spring and summer months. Almost 45% of the Mediterranean juvenile population has migrated from the Atlantic. Loggerheads feed in the Alboran Sea and
4715-636: The Atlantic, Indian, and Pacific Oceans and the Mediterranean Sea. In the Atlantic Ocean, the greatest concentration of loggerheads is along the southeastern coast of North America and in the Gulf of Mexico. Very few loggerheads are found along the European and African coastlines. Florida is the most popular nesting site, with more than 67,000 nests built per year. Nesting extends as far north as Virginia , as far south as Brazil, and as far east as
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4830-481: The Gulf of California. In 2000, between 2,600 and 6,000 loggerheads were estimated to have been killed by pelagic longlining in the Pacific. Fishing gear is the biggest threat to loggerheads in the open ocean. They often become entangled in longlines or gillnets . According to the 2009 status review of loggerheads by the Fisheries Service, drowning from entanglement in longline and gillnet fishing gear
4945-699: The Mediterranean, Oman, Japan, and Brazil are unknown. Nesting loggerheads have a straight carapace length of 70–109 cm (28–43 in). Because of the large range, carapace length is not a reliable indicator of sexual maturity. Their estimated maximum lifespan is 47–67 years in the wild. Female loggerheads first reproduce between the ages of 17 and 33, and their mating period may last more than six weeks. They court their mates, but these behaviors have not been thoroughly examined. Male forms of courtship behavior include nuzzling, biting, and head and flipper movements. Studies suggest females produce cloacal pheromones to indicate reproductive ability. Before mating,
5060-406: The abdomen), histological examination (cell anatomy), and radioimmunological assays (immune study dealing with radiolabeling ). Lachrymal glands located behind each eye allow the loggerhead to maintain osmotic balance by eliminating the excess salt obtained from ingesting ocean water. On land, the excretion of excess salt gives the false impression that the turtle is crying. The urea content
5175-415: The ability to pull its head into its shell, and had a long neck and a long, spiked tail ending in a club, somewhat like an ankylosaur . Septicemic cutaneous ulcerative disease (SCUD) or "shell rot" causes ulceration of the shell. This is caused by bacteria or fungi entering through an abrasion , and poor animal husbandry . The disease progresses to a septicemic infection causing the degradation of
5290-413: The addition of keratin layers to the base of each scute. Aquatic chelonii shed individual scutes. The scute effectively forms the skin over the underlying bony structures; there is a very thin layer of subcutaneous tissue between the scute and the skeleton. The scutes can be brightly colored in some species, and turtle shells often follow Thayer's law with carapace usually being a darker patterning than
5405-474: The ancient trading city of Kaunos are a short boat trip across the river. The south of Dalyan on the Mediterranean coast, lies İztuzu Beach , near the village of the same name is a popular area for sunbathing and swimming. There are regular boat and minibus ( dolmuş ) services to the beach. Visitors should be aware of the wooden stakes in the beach to mark nesting sites. The road route is particularly scenic, offering views of Sülüngür Lake. In 2008 İztuzu Beach
5520-420: The bridge of the shell. The plastron is made up of nine bones and the two epiplastra at the anterior border of the plastron are homologous to the clavicles of other tetrapods. The rest of the plastral bones are homologous to the gastralia of other tetrapods. The plastron has been described as an exoskeleton , like osteoderms of other reptilians; but unlike osteoderms, the plastron also possesses osteoblasts ,
5635-489: The brighter area over the water which is the consequence of the reflection of moon and star light. Confused by the brighter artificial light, they navigate inland, away from the protective waters, which exposes them to dehydration and predation as the sun rises. Artificial lighting causes tens of thousands of hatchling deaths per year. Destruction and encroachment of habitat by humans is another threat to loggerhead sea turtles. Optimum nesting beaches are open-sand beaches above
5750-426: The brighter horizon created by the reflection of the moon and starlight off the water's surface. Hatchlings can lose up to 20% of their body mass due to evaporation of water as they journey from nest to ocean. They initially use the undertow to push them five to 10 m away from the shore. Once in the ocean, they swim for about 20 hours, taking them far offshore. An iron compound, magnetite , in their brains allows
5865-413: The carapace represents transformed vertebrae and ribs. While other tetrapods have their scapula, or shoulder blades , found outside of the ribcage, the scapula for turtles is found inside the ribcage. The shells of other tetrapods, such as armadillos , are not linked directly to the vertebral column or rib cage allowing the ribs to move freely with the surrounding intercostal muscle. However, analysis of
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#17327729492125980-622: The central North Pacific have been revealed through telemetry studies. Along with these foraging habitats, high levels of bycatch from industrial-scale fisheries have been found to overlap; with drift gillnets in the past and longline fisheries presently. Many juvenile loggerheads aggregate off the coast of Baja California Sur, Mexico, where small coastal fisheries increase these turtles' mortality risk; fishers have reported catching dozens of loggerheads with bottom-set gear per day per boat. The most common commercial fishery that accidentally takes loggerheads are bottom trawls used for shrimp vessels in
6095-529: The coast of Baja California, where upwelling provides rich feeding grounds for juvenile turtles and subadults . Nesting sites along the eastern Pacific Basin are rare. mtDNA sequence polymorphism analysis and tracking studies suggest 95% of the population along the coast of the Americas hatch on the Japanese Islands in the western Pacific. The turtles are transported by the prevailing currents across
6210-418: The coldest months, they submerge for up to seven hours at a time, emerging for only seven minutes to breathe. Although outdone by freshwater turtles , these are among the longest recorded dives for any air-breathing marine vertebrate. During their seasonal migration, juvenile loggerheads have the ability to use both magnetic and visual cues. When both aids are available, they are used in conjunction; if one aid
6325-468: The complete enclosure of the shell likely evolved by including dermal armor into the rib cage. The turtle's shell is an important study, not just because of the apparent protection it provides for the animal but also as an identification tool, in particular with fossils, as the shell is one of the likely parts of a turtle to survive fossilization. Hence understanding the shell structure in living species provides comparable material with fossils. The shell of
6440-409: The conflict is over access to good foraging grounds. Further aggression has also been reported in captive loggerheads. The turtles are seemingly territorial , and will fight with other loggerheads and sea turtles of different species. The loggerhead sea turtle is omnivorous, feeding mainly on bottom-dwelling invertebrates , such as gastropods , bivalves , decapods , and horseshoe crabs . It has
6555-445: The dermal bone. The spine and expanded ribs are fused through ossification to dermal plates beneath the skin to form a hard shell. Exterior to the skin the shell is covered by scutes , which are horny plates made of keratin that protect the shell from scrapes and bruises. A keel , a ridge that runs from front to the back of the animal is present in some species, these may be single, paired or even three rows of them. In most turtles
6670-457: The dermis, osteoderms , fused first to each other and then to the ribs beneath them. The theory persisted into the 21st century, when Olivier Rieppel proposed a hypothetical turtle precursor, its back covered by bony armour plates in the dermis, which he called the "Polka Dot Ancestor". Michael Lee proposed that the transformation of the carapace began with an unarmoured parareptile and then an armoured pareiasaur, and ended with modern turtles with
6785-425: The development of the turtle embryo , the ribs grow sideways into the carapacial ridge, unique to turtles, entering the dermis of the back to support the carapace. The development is signalled locally by fibroblast growth factors including FGF10 . Zoologists have sought to explain the evolutionary origin of the turtles, and in particular of their unique carapace. In 1914, J. Versluys proposed that bony plates in
6900-421: The edge of the shell are 12 pairs of marginal scutes. All these scutes are aligned so that for the most part the sutures between the bones are in the middle of the scutes above. At the anterior of the shell there may be a cervical scute (sometimes incorrectly called a nuchal scute) however the presence or absence of this scute is highly variable, even within species. On the plastron there are two gular scutes at
7015-408: The evolution from amphibians to terrestrial amniotes, transition in a wide variety of skin structures occurred. Ancestors of turtles likely diverged from amphibians to develop a horny cover in their early terrestrial ancestral forms. The carapacial ridge plays an essential role in the development of the turtle shell. Embryological analyses show that the carapacial ridge initiates the formation of
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#17327729492127130-441: The eyes, cause permanent blindness. Trematodes of the family Spirorchiidae inhabit tissues throughout the body of the loggerhead, including vital organs, such as the heart and the brain. Trematode infection can be highly debilitating. For example, inflammatory trematode lesions can cause endocarditis and neurological disease . A nematode , Angiostoma carettae , also infects loggerheads, causing histologic lesions in
7245-410: The females can use to camouflage the nest. The nesting area must be selected carefully because it affects characteristics such as fitness, emergence ratio, and vulnerability to nest predators. Loggerheads have an average clutch size of 112.4 eggs. Many human activities have negative effects on loggerhead sea turtle populations. The prolonged time required for loggerheads to reach sexual maturity and
7360-678: The females' brief visits to construct nests and deposit eggs. Hatchling loggerhead turtles live in floating mats of Sargassum algae. Adults and juveniles live along the continental shelf as well as in shallow coastal estuaries. In the northwestern Atlantic Ocean, age plays a factor in habitat preference. Juveniles are more frequently found in shallow estuarine habitats with limited ocean access compared to non-nesting adults. Loggerheads occupy waters with surface temperatures ranging from 13.3–28 °C (56–82 °F) during non-nesting season. Temperatures from 27–28 °C (81–82 °F) are most suitable for nesting females. Juvenile loggerheads share
7475-434: The following two centuries, with the combination Caretta caretta first introduced in 1873 by Leonhard Stejneger. The English common name "loggerhead" refers to the animal's large head. The loggerhead sea turtle belongs to the family Cheloniidae , which includes all extant sea turtles except the leatherback sea turtle . The subspecific classification of the loggerhead sea turtle is debated, but most authors consider it
7590-410: The fossil specimens which show forked ends. This evidence shows a gradual change from paired gastralia, to paired and fused gastralia, and finally to the modern plastron across these three specimens. In certain families there is a hinge between the pectoral and abdominal scutes allowing the turtle to almost completely enclose itself. In certain species the sex of a testudine can be told by whether
7705-455: The front half of the plastron and the hyoplastron contains the anterior bridge strut. The posterior half is made up of two hypoplastra (containing the posterior bridge strut) and the rear is a pair of xiphiplastra. Overlying the boney elements are a series of scutes, which are made of keratin and are a lot like horn or nail tissue. In the center of the carapace are five vertebral scutes and out from these are four pairs of costal scutes. Around
7820-489: The front, followed by a pair of pectorals, then abdominals, femorals and lastly anals. A particular variation is the Pleurodiran turtles have an intergular scute between the gulars at the front, giving them a total of 13 plastral scutes. Compared to the 12 in all Cryptodiran turtles. The carapace is the dorsal (back), convex part of the shell structure of a turtle , consisting of the animal's ossified ribs fused with
7935-405: The full length of the northern Pacific, one of the longest migration routes of any marine animal. The return journey to the natal beaches in Japan has been long suspected, although the trip would cross unproductive clear water with few feeding opportunities. Evidence of a return journey came from an adult female loggerhead named Adelita, which in 1996, equipped with a satellite tracking device, made
8050-539: The function of mediating the ribs and carapace development later. The PAX1 and Sonic hedgehog gene ( Shh ) serve as key regulators during the development of the vertebral column. Shh expression in the neural tube is essential for the maintenance of Pax1 expression in the ventral sclerotome and thus plays a key role in carapacial rib development. Genetic observations of Pax1 and Shh further provide an understanding in key gene expression that could potentially be responsible for changing turtle morphology. During
8165-445: The high mortality rates of eggs and young turtles from natural phenomena compound the problems of population reduction as a consequence of human activities. Loggerhead sea turtles were once intensively hunted for their meat and eggs ; consumption has decreased, however, due to worldwide legislation. Despite this, turtle meat and eggs are still consumed in countries where regulations are not strictly enforced. In Mexico, turtle eggs are
8280-409: The high-tide line. However, beach development deprives them of suitable nesting areas, forcing them to nest closer to the surf. Urbanization often leads to the siltation of sandy beaches, decreasing their viability. Construction of docks and marinas can destroy near-shore habitats. Boat traffic and dredging degrades habitat and can also injure or kill turtles when boats collide with turtles at or near
8395-399: The immediate vicinity. Escalation is determined by several factors, including hormone levels, energy expenditure, expected outcome, and importance of location. At all stages, an upright tail shows willingness to escalate, while a curled tail shows willingness to submit. Because higher aggression is metabolically costly and potentially debilitating, contact is much more likely to escalate when
8510-529: The impact of raccoon predation on loggerhead sea turtle eggs. Up to 40% of nesting females around the world have wounds believed to come from shark attacks. Infectious bacteria such as Pseudomonas and Salmonella attack loggerhead hatchlings and eggs. Fungi such as Penicillium infect loggerhead sea turtle nests and cloacae. Fibropapillomatosis disease caused by a form of the herpes-type virus threatens loggerheads with internal and external tumors. These tumors disrupt essential behaviors and, if on
8625-414: The introduction of the red fox ( Vulpes vulpes ) by British settlers in the 19th century led to significant reductions in loggerhead sea turtle populations. In one coastal section in eastern Australia during the 1970s, predation of turtle eggs destroyed up to 95% of all clutches laid. Aggressive efforts to destroy foxes in the 1980s and 1990s has reduced this impact; however, it is estimated that it will be
8740-865: The juvenile matures, its swimming method is progressively replaced with the adult's alternating-limb method. They depend entirely on this method of swimming by one year old. Water temperature affects the sea turtle's metabolic rate. Lethargy is induced at temperatures between 13 and 15 °C (55 and 59 °F). The loggerhead takes on a floating, cold-stunned posture when temperatures drop to around 10 °C (50 °F). However, younger loggerheads are more resistant to cold and do not become stunned until temperatures drop below 9 °C (48 °F). The loggerheads' migration helps to prevent instances of cold-stunning. Higher water temperatures cause an increase in metabolism and heart rate. A loggerhead's body temperature increases in warmer waters more quickly than it decreases in colder water; their critical thermal maximum
8855-405: The largest specimens weighing in at more than 450 kg (1,000 lb). The skin ranges from yellow to brown in color, and the shell is typically reddish brown. No external differences in sex are seen until the turtle becomes an adult, the most obvious difference being the adult males have thicker tails and shorter plastrons (lower shells) than the females. The loggerhead sea turtle is found in
8970-492: The loggerhead sea turtle is only apparent in adults. Adult males have longer tails and claws than females. The males' plastrons are shorter than the females', presumably to accommodate the males' larger tails. The carapaces of males are wider and less domed than the females', and males typically have wider heads than females. The sex of juveniles and subadults cannot be determined through external anatomy, but can be observed through dissection, laparoscopy (an operation performed on
9085-754: The major nesting areas, with the Great Barrier Reef deemed an important nesting area. Pacific loggerheads occasionally nest in Vanuatu and Tokelau . Yakushima Island is the most important site, with three nesting grounds visited by 40% of all nearby loggerheads. After nesting, females often find homes in the East China Sea, while the Kuroshio Current Extension's Bifurcation region provides important juvenile foraging areas. Eastern Pacific populations are concentrated off
9200-493: The male approaches a female and attempts to mount her, while she resists. Next, the male and female begin to circle each other. If the male has competitors, the female may let the males struggle with each other. The winner then mounts the female; the male's curved claws usually damage the shoulders of the female's shell during this process. Other courting males bite the male while he is attempting to copulate, damaging his flippers and tail, possibly exposing bones. Such damage can cause
9315-409: The male to dismount and may require weeks to heal. While nesting, females produce an average of 3.9 egg clutches, and then become quiescent, producing no eggs for two to three years. Unlike other sea turtles, courtship and mating usually do not take place near the nesting beach, but rather along migration routes between feeding and breeding grounds. Recent evidence indicates ovulation in loggerheads
9430-402: The middle of the clutch tend to be the largest, grow the fastest, and be the most active during the first few days of sea life. After incubating for around 80 days, hatchlings dig through the sand to the surface, usually at night, when darkness increases the chance of escaping predation and damage from extreme sand surface temperatures is reduced. Hatchlings enter the ocean by navigating toward
9545-459: The nesting season, on or near the beach where they hatched. They exit the water, climb the beach, and scrape away the surface sand to form a body pit. With their hind limbs, they excavate an egg chamber in which the eggs are deposited. The females then cover the egg chamber and body pit with sand, and finally return to the sea. This process takes one to two hours, and occurs in open sand areas or on top of sand dunes, preferably near dune grasses that
9660-695: The nesting turtles. In addition to the Greek coast, the coastlines of Cyprus and Turkey are also common nesting sites. One record of this turtle was made in Ireland when a specimen washed ashore on Ballyhealy Beach in County Wexford . Another records one specimen being washed up on a beach in County Donegal, Ireland. Loggerhead sea turtles spend most of their lives in the open ocean and in shallow coastal waters. They rarely come ashore besides
9775-425: The open sea, loggerheads eat jellyfish , floating molluscs, floating egg clusters, squid , and flying fish . Loggerheads crush prey with their large and powerful jaws. Projecting scale points on the anterior margin of the forelimbs allow manipulation of the food. These points can be used as "pseudo-claws" to tear large pieces of food in the loggerhead's mouth. The loggerhead will turn its neck sideways to consume
9890-430: The plastron evolved were once floating ventral ribs. During turtle evolution, there was probably a division of labor between the ribs, which specialized to stabilize the trunk, and the abdominal muscles, which specialized for respiration, and these changes took place 50 million years before the shell was fully ossified. The discovery of an ancestral turtle fossil, Pappochelys rosinae, provides additional clues as to how
10005-411: The plastron formed. Pappochelys serves as an intermediate form between two early stem-turtles, E. africanus and Odontochelys, the latter of which possesses a fully formed plastron. In place of a modern plastron, Pappochelys has paired gastralia, like those found in E. africanus . Pappochelys is different from its ancestor because the gastralia show signs of having once been fused, as indicated by
10120-409: The plastron is concave , male or convex , female. This is because of the mating position; the male's concave plastron allows it to more easily mount the female during copulation. The plastral scutes join along a central seam down the middle of the plastron. The relative lengths of the seam segments can be used to help identify a species of turtle . There are six laterally symmetric pairs of scutes on
10235-491: The plastron, though there are exceptions. Moustakas-Verho and Cherepanov's embryological study reveals that the patterning of the plastral scutes appear independent from the patterning of carapacial scutes, suggesting that the carapace and plastron evolved separately. The appearance of scutes correlates to the transition from aquatic to terrestrial mode of life in tetrapods during the Carboniferous period (340 Ma). In
10350-406: The plastron. This phenomenon occurs in turtle development, but instead of experiencing complete loss of the sternum the turtle body plan repurposes the bone into the form of the plastron, although other analyses find that the endochondral sternum is absent and replaced by the exoskeletal plastron. The ventral ribs are effectively not present, replaced by the plastron, unless the gastralia from which
10465-446: The plastron: gular, humeral, pectoral, abdominal, femoral, and anal (going from the head to the tail down the seam); the abdominal and gular scute seams are approximately the same length, and the femoral and pectoral seams are approximately the same length. The gular scute or gular projection on a turtle is the most anterior part of the plastron, the underside of the shell. Some tortoises have paired gular scutes , while others have
10580-604: The posterior coracoid and their large and wide terminal phalanges creating shovel-like "hands". Fossoriality may have helped Eunotosaurus survive the global mass extinction at the end of the Permian period, and could have played an essential role in the early evolution of shelled turtles. A stem-turtle from the Middle Triassic of Germany, some 240 million years ago, Pappochelys , has more distinctly broadened ribs, T-shaped in cross-section. They vary in shape along
10695-426: The posterior of the shell is the pygal bone and in front of this nested behind the eighth pleurals is the suprapygal. Between each of the pleurals are a series of neural bones, which although always present are not always visible, in many species of Pleurodire they are submerged below the pleurals. Beneath the neural bone is the neural arch which forms the upper half of the encasement for the spinal cord. Below this
10810-413: The rest of the vertebral column. Some species of turtles have some extra bones called mesoplastra, which are located between the carapace and plastron in the bridge area. They are present in most Pelomedusid turtles. The skeletal elements of the plastron are also largely in pairs. Anteriorly there are two epiplastra, with the hyoplastra behind them. These enclose the singular entoplastron. These make up
10925-460: The same position with their eyes tightly shut, and are slow to react. Loggerheads spend up to 85% of their day submerged, with males being the more active divers than females. The average duration of dives is 15–30 min, but they can stay submerged for up to four hours. Juvenile loggerheads and adults differ in their swimming methods. A juvenile keeps its forelimbs pressed to the side of its carapace, and propels itself by kicking with its hind limbs. As
11040-438: The scutes mentioned prior or the ribs found internally of the shell. Many ribs can be found within the shell and throughout the shell. The rib structures provide extra structural support but allows the shells to deform elastically depending on the situation the turtle is in (i.e., predatory escape). Nonstructural mechanisms have also been in the turtle shell that aids the turtle during locomotion . A mucus film covers parts of
11155-475: The sea to Köyceğiz Lake where another large town of the region, Köyceğiz , is located. The fish spawn there, and when returning to the sea they are caught in the "dalyans". According to the Turkish etymological dictionary Nişanyan Sözlük, Dalyan (ta aliana) derives from the Greek word aliia (αλιεία), which means fishing or fishery. In addition to its attraction as a tourist destination, the region around Dalyan
11270-415: The shell is relatively uniform in structure, species variation in general shape and color being the main differences. However, the soft shell turtles, pig-nose turtles and the leatherback sea turtle have lost the scutes and reduced the ossification of the shell. This leaves the shell covered only by skin . These are all highly aquatic forms. The evolution of the turtle's shell is unique because of how
11385-417: The shell, allowing some physical protection and also reducing friction and drag . The bones of the shell are named for standard vertebrate elements. As such the carapace is made up of eight pleurals on each side, these are a combination of the ribs and fused dermal bone. Outside of this at the anterior of the shell is the single nuchal bone, a series of twelve paired periphals then extend along each side. At
11500-409: The shell. A collection of 7,000 nematodes from 111 genera were found on the turtles studied. Hatchlings range in color from light brown to almost black, lacking the adult's distinct yellows and reds. Upon hatching, they measure about 4.6 cm (1.8 in) and weigh about 20 g (0.7 oz). The eggs are typically laid on the beach in an area above the high-tide line . The eggs are laid near
11615-487: The spine. A Late Triassic stem-turtle from Guizhou , China, Eorhynchochelys , is a much larger animal, up to 1.8 metres (5.9 ft) long, with a long tail, and broadened but not overlapping ribs; like the earlier fossils, it has small teeth. Also in the Late Triassic, some 220 million years ago, the freshwater Odontochelys semitestacea of Guangling in southwest China has a partial shell, consisting of
11730-428: The surface. Plastron The turtle shell is a shield for the ventral and dorsal parts of turtles (the order Testudines), completely enclosing all the vital organs of the turtle and in some cases even the head. It is constructed of modified bony elements such as the ribs, parts of the pelvis and other bones found in most reptiles. The bone of the shell consists of both skeletal and dermal bone , showing that
11845-480: The sutures into which they insert, known as the Bridge carapace suture. In the shell there is a turtle 's epidermis layer. This layer is important to the strength of the shell surrounding it. In an international study, the layer can be as thick as two to four cells. Even with such a small thickness, the epidermis allows the deformation the shell can experience and provides the shell more support. The epidermis layer
11960-700: The torn food on the scale points. Inward-pointing, mucus -covered papillae found in the fore region of the loggerhead's esophagus filter out foreign bodies, such as fish hooks. The next region of the esophagus is not papillated, with numerous mucosal folds. The digestion rate in loggerheads is temperature-dependent; it increases as temperature increases. Loggerheads have numerous predators, especially early in their lives. Egg and nestling predators include ghost crabs , oligochaete worms , some beetles , flesh fly larvae , some ants , flesh flies , snakes , gulls , corvids , opossums , bears , rats , armadillos , mustelids , skunks , canids like coyotes , dingos ,
12075-405: The transitional fossil, Eunotosaurus africanus shows that early ancestors of turtles lost that intercostal muscle usually found between the ribs. The plastron (plural: plastrons or plastra) is the nearly flat part of the shell structure of a turtle , what one would call the belly or ventral surface of the shell. It also includes within its structure the anterior and posterior bridge struts and
12190-410: The turtle shell. It causes axial arrest which causes the ribs to be dorsalized, the shoulder girdle to be rearranged and encapsulated in the rib cage, and the carapace to develop. Odontochelys semitestacea presents evidence of axial arrest that is observed in embryos but lacks fan-shaped ribs and a carapace. This suggests that the primitive carapacial ridge functioned differently and must have gained
12305-424: The turtle stem and on to more crown-ward turtles". Tyler Lyson and colleagues suggest that Eunotosaurus might imply a fossorial origin for the turtles. During the Permian, the broadened ribs may have provided great stability in burrowing, giving a body shape resembling the extant fossorial gopher tortoise , with strong shoulders and forelimbs, and increased muscle attachment structures such as their tubercle on
12420-463: The turtles to perceive the Earth's magnetic field , for navigation. Many hatchlings use Sargassum in the open ocean as protection until they reach 45 cm (18 in). Hatchling loggerheads live in this pelagic environment until they reach juvenile age, and then they migrate to nearshore waters. When ocean waters cool, loggerheads must migrate to warmer areas or hibernate to some degree. In
12535-648: The turtles' nesting grounds in Turkey. The beach is closed between 20.00 and 8:00 hours during the period that the turtles lay their eggs and hatchlings go out to sea (May to October). Loggerhead sea turtle The loggerhead sea turtle ( Caretta caretta ) is a species of oceanic turtle distributed throughout the world. It is a marine reptile , belonging to the family Cheloniidae . The average loggerhead measures around 90 cm (35 in) in carapace length when fully grown. The adult loggerhead sea turtle weighs approximately 135 kg (298 lb), with
12650-451: The turtles. Loss of suitable nesting beaches and the introduction of exotic predators have also taken a toll on loggerhead populations. Efforts to restore their numbers will require international cooperation, since the turtles roam vast areas of ocean and critical nesting beaches are scattered across several countries. Carl Linnaeus gave the loggerhead its first binomial name, Testudo caretta , in 1758. Thirty-five other names emerged over
12765-457: The water so the hatchlings can return to the sea. The loggerhead's sex is dictated by the temperature of the underground nest. Incubation temperatures generally range from 26–32 °C (79–90 °F). Sea turtle eggs kept at a constant incubating temperature of 32 °C become females. Eggs incubating at 28 °C become males. An incubation temperature of 30 °C results in an equal ratio of male to female hatchlings. Hatchlings from eggs in
12880-607: The year 2020 before populations will experience complete recovery from such dramatic losses. Along the southeastern coast of the United States, the raccoon ( Procyon lotor ) is the most destructive predator of nesting sites. Mortality rates of nearly 100% of all clutches laid in a season have been recorded on some Florida beaches. This is attributed to an increase in raccoon populations, which have flourished in urban environments. Aggressive efforts to protect nesting sites by covering them with wire mesh has significantly reduced
12995-866: Was a complete isolation of the Atlantic and Pacific populations of loggerheads. During the most recent ice age , the beaches of southeastern North America were too cold for sea turtle eggs. As the Earth began to warm, loggerheads moved farther north, colonizing the northern beaches. Because of this, turtles nesting between North Carolina and northern Florida represent a different genetic population from those in southern Florida. The distinct populations of loggerheads have unique characteristics and genetic differences. For example, Mediterranean loggerheads are smaller, on average, than Atlantic Ocean loggerheads. North Atlantic and Mediterranean loggerhead sea turtles are descendants of colonizing loggerheads from Tongaland , South Africa. South African loggerhead genes are still present in these populations today. The loggerhead sea turtle
13110-473: Was proclaimed winner in the category Best Open Space (Europe) by The Times because of the eco-friendly exploitation of the beach. In 2011 Dalyan and İztuzu Beach were proclaimed Best Beach Destination of Europe by Dutch holiday assessment website Zoover. The beach is well known for the Caretta caretta ( Loggerhead sea turtle ), an endangered species that has existed for about 45 million years. International animal protection organizations monitor and protect
13225-612: Was temporarily stopped after Prince Philip called for a moratorium and in 1988 the beach and its hinterland were declared a protected area, viz. Köyceğiz-Dalyan Special Environmental Protection Area . Life in Dalyan revolves around the Dalyan Çayı River which flows past the town. The boats that ply up and down the river, navigating the maze of reeds, are the preferred means of transport to local sites. Dalyan means " fishing weir " in Turkish . Bass, Mullet and Sea Bream swim upstream from
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