Turtles

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Turtles
European pond turtle (Emys orbicularis), the only species of turtle native to Germany

European pond turtle ( Emys orbicularis ), the
only species of turtle native to Germany

Systematics
Sub-stem : Vertebrates (vertebrata)
Superclass : Jaw mouths (Gnathostomata)
Row : Land vertebrates (Tetrapoda)
without rank: Amniotes (Amniota)
without rank: Sauropsida
Order : Turtles
Scientific name
Testudinata
Linnaeus , 1758
Submissions

The turtles (Testudinata, or Testudines, if the crown group is meant; formerly also Chelonia from ancient Greek χελώνιον "turtle") are an order of the Sauropsida and appeared for the first time more than 220 million years ago in the Carnic (Upper Triassic). In the classical system they are counted among the reptiles or reptiles ; These names stand for a taxon that is paraphyletic in its traditional scope and are therefore only informal collective terms today.

There are currently 341 species with over 200 subspecies. The turtles have adapted to the most varied of biotopes and ecological niches . The range extends from Mediterranean tortoise species , gopher or desert tortoises and the particularly numerous, smaller water turtle species in North America and Southeast Asia to growing river turtles in South America, giant tortoises on some island groups, soft turtles in Asia and snake-necked turtles in Australia to the largest, the leatherback turtles , which form a family of their own alongside the sea ​​turtles .

Turtles are cold-blooded , egg-laying reptiles. In fossil history, they are most closely related to some basal diapsids such as Odontochelys semitestacea and Sinosaurosphargis yunguiensis .

The adaptability of the turtles has ensured their continued existence up to the present day. However, today many species are acutely endangered by human influences.

distribution

Distribution: land, water and pond turtles (black, but the habitat of Emys orbicularis is missing ),
sea ​​turtles (blue)

With the exception of the polar regions, turtles colonize all continents. They occur in various areas of land, in tropical forests and swamps, in deserts and semi-deserts, lakes, ponds, rivers, in brackish water areas and in seas, in temperate, tropical and subtropical climates.

In Europe there are only nine autochthonous species, four terrestrial and five aquatic turtle species, in addition to sea turtles . Germany, Austria and Switzerland are home to only one native species of turtle, the nominate form of the European pond turtle ( Emys orbicularis orbicularis ).

Physique and lifestyle

Generalized arrangement of the horn shields (scuta) on the carapace
Black-buttoned mute turtle with characteristic expression of the vertebral shields
Smooth softshell turtle, no horn shields, only skin covers the bone shell
The carapace (back shield) of a vulture turtle

Structure of the tank ( Pantex )

For turtles, the shell, which already accounts for about 30% of the weight, is undoubtedly the most important anatomical characteristic. No other vertebrate shows a comparable anatomy. Similar to the exoskeleton of insects, the shell of the turtle, which is made up of the back armor ( carapace ) and abdominal armor ( plastron ) , encloses all important organs and body regions.

The bone armor consists of massive bone plates that form a rib cage that evolved from the vertebral arches and ribs of the endoskeleton of vertebrates . In contrast to all other vertebrates with a shoulder girdle , the shoulder bone (lat. Scapula ) has pushed itself under the ribs. This largely rigid bone armor requires an adaptation of the breathing, which must be supported by moving the extremities with the help of strong muscles.

Depending on the species, there is a leather-like layer of skin over the bone armor (e.g. in softshell turtles ) or the typical layer of horny shields ( scuta ), which in turn consist of keratin . The color of the horn shield depends mainly on the origin of the turtle, because most species are color-matched to their habitat .

In ornamental , letter jewelery , real jewelery and mute turtles , the horn shields are regularly renewed as the older outer horn shields come loose and the newly formed horn shields appear underneath. In other turtles, growth rings appear and the outer horn shields only wear off somewhat through external abrasion.

These horn shields can be divided into the following groups, with species-related deviations in number and presence:

Carapace horn shields

(from cranial to caudal or from front to back)

  • 1 neck shield ( cervicale or nuchal )
  • 24 edge shields ( marginalia )
    • the last two marginal shields are the postcentralia and together form the supracaudal or tail shield (supracaudal, syn .: caudal), in some species this is also undivided
  • 5 eddy shields ( Vertebralia )
  • 8 rib shields ( pleuralia or costalia )

Horn shields of the belly armor ( plastron )

(from cranial to caudal or from front to back)

  • 2 throat shields ( Gularia )
  • 2 arm shields ( Humeralia )
  • 2 axillary shields ( axillaria )
  • 2 breast shields ( pectoralia )
  • 2 abdominal shields ( abdominalia )
  • 2 hip shields ( inguinalia )
  • 2 leg shields ( femoralals )
  • 2 aftershields ( Analia )

The seams and interlocking points of the horn and bone armor do not lie on top of each other, but are shifted against each other. This increases the strength of the armor even further. The appearance of the entire tank differs greatly depending on the species. In many species, especially in adolescence, the back armor has one or three longitudinal keels. In the case of the mute turtles and the Chinese three-keeled turtles, these strongly pronounced humps and keels are even named after them. Different species (for example the box turtles and the hinged turtles ) can fold up their belly armor with the help of a hinge and thus close the entire armor. The folding turtles have two hinges and can therefore close the front and rear openings independently of each other. The hinge in the carapace of the jointed tortoises has a similar function .

Some scientists assume that the shell of the turtle evolved as an adaptation to the aquatic environment. The rigid body then enabled faster progress underwater, especially in contrast to the meandering movements of other reptiles. However, the oldest known turtle fossils already show a highly developed shell, so that one can only speculate about its origins and its development.

Sensory performances

Turtles see very well. They can differentiate colors better than humans because their eyes, like all reptiles, have four different color receptors. This enables you to perceive parts of the near infrared and ultraviolet radiation. Gray tones, on the other hand, seem to differentiate them less.

The lens of the turtle is designed to compensate for the angle of refraction of water. This allows the animals to clearly see enemies and food in the water. Hunting turtles can see both spatially and in the panorama by changing their eye position. The speed of visually perceived movements has an impact on the escape response . If you approach a turtle very slowly, it will flee later than if you approach it quickly.

The sense of smell is particularly strong in turtles. Water turtles smell by chewing and pumping movements of the lower jaw and neck. The olfactory receptors are located in the throat. By the smell they recognize suitable food or soil in which they can bury their eggs. In addition, sexual partners are recognized by their smell (in aquatic species also underwater), probably even over greater distances.

Turtles have fully developed inner and middle ears, but no outer ear. Therefore, they do not hear sounds to the same extent as humans. They perceive sound waves of around 100 Hz to 1000 Hz, i.e. above all deep vibrations (impact sound) from their environment, possibly also feeding noises from their own species. According to a study from Italy, female turtles of the genus Testudo even respond to acoustic signals from the males during mating, whereby they seem to prefer rapid noises and high-pitched tones (small males).

Turtles can measure their cognitive abilities with all other reptiles. This is how they memorize sources of food and escape routes. Your sense of direction is also excellent and seems to increase with increasing age.

Other well-developed sensory services are pain perception, temperature and balance.

Utterances and communication

Turtles are mostly silent. Exceptions, however, are startle reactions. Here these animals expel air by quickly pulling their heads back, which creates a hissing hissing sound. Occasionally hissing threatening sounds can be heard in turtles. Males of many tortoise species make beeping or panting sounds when mating, similar to females when they occasionally fight with other females for the best egg-laying places. Tortoises can have a kind of hiccup for a short time after hastily eating fruit or small snails , which makes a corresponding noise.

The latest research by a team led by Camila Ferrera from the Brazilian Wildlife Conservation Society and Richard Vogt from the Amazon Research Institute in Manaus has found that acoustic communication between individuals takes place with low tones. Mother animals communicate with newly hatched animals. Embryos exchange acoustically with one another - before hatching - in order to possibly synchronize hatching.

Locomotion

Turtles move around in the reptile-typical winding movements both on land and in the water, with the shell being carried in the air on land. This type of locomotion lowers the energy requirements when moving in the water, but can sometimes seem awkward on land. Only sea turtles have developed a method of locomotion that is unique for reptiles. They flap up and down the front limbs that have formed into fins. In this way, they achieve high speeds under water with optimized energy requirements, which enables them to cover longer distances. The limbs of tortoises and freshwater and brackish water turtles are also adapted to the respective habitat. In most cases, the connection to the water can be determined by the presence and the expression of webbed feet, especially on the rear extremities. The legs of turtles that inhabit hot steppe areas, on the other hand, are columnar and protected all around against injury and dehydration by strong horny scales.

Food intake and diet

Teeth were still discovered in fossil turtles that are 220 million and 160 million years old , but they have regressed in the course of evolution . Today's turtles have no teeth, but rather mandibular ridges made of horny substance that have been converted into powerful cutting tools , which in their entirety form the beak . Like all reptiles, turtles do not chew their food, but instead either gobble it up whole, or tear off pieces with their mouths, using the front limbs for help.

Head and neck shape of a sucker (fringed tortoise)

Turtles are mostly omnivores (so-called omnivores ). Depending on the species, however, the vegetal ( herbivorous ) or the carnal ( carnivorous ) diet usually predominates . Some species, especially those living in water, switch from a protein-rich diet with aquatic insects as young animals to a lower-energy, but easy-to-obtain vegetable diet when they grow up are. Turtles need calcium-rich food for the comparatively large bone skeleton and in some cases for the formation of hard-shelled eggs. The food is usually very varied, because the animals are not very particular about what to eat. Depending on the species, their food spectrum ranges from meadow herbs, flowers, fruits, aquatic plants and algae to insects, worms, snails, fish, starfish, crabs and jellyfish to carrion and waste products from mammals.

However, some species are downright nutrition specialists, such as B. the leatherback turtle , which specializes in jellyfish, or the Malaysian pond turtle , whose English name, Snail Eating Turtle, and powerful jaws reveal the preference for snail snails. Some other turtle species have also adapted their physique to special hunting methods, e.g. B. the vulture turtle , which waits quietly with its mouth open until a fish is interested in the worm-shaped tip in its mouth. Another unusual fishing method is practiced by the fringed tortoise (Mata-Mata), which lurks in the mud with a shell overgrown with algae and sucks in its prey by suddenly tearing open its huge throat.

Sex differences and reproduction

Every year, thousands of olive ridged turtles ( Lepidochelys olivacea ) arrive to lay their eggs in the protected area of Playa de Escobilla on the Mexican Pacific coast
Olive ridged turtles lay many and relatively small eggs
An embryo of the olive ridged turtle
Hatching process in a Greek tortoise ( Testudo hermanni )

A direct comparison between sexually mature males and females shows that the excretion opening in the root of the tail of the female, the cloaca , is closer to the tank edge, while that of the male is closer to the tail end. The male's tail is usually significantly longer and wider at the base, as it houses the penis, which is only everted for copulation . Other common gender differences are smaller body size and a more inwardly curved belly armor in the males, which facilitates copulation. In addition, there are secondary sexual characteristics that are restricted to individual genera, species or even subspecies, such as elongated front claws of the male in the silver turtle or a different coloration of the iris in some box turtles and some subspecies of the European pond turtle. The secondary sexual characteristics are not yet recognizable in the hatchling, but are only developed in advance of sexual maturity.

During the mating season, the males, who colonize other ecological niches in some species, seek out the females specifically. You will probably be guided by odor hormones ( pheromones ). In most species, the actual mating act is preceded by a courtship, which seems rather rough to humans. Depending on the species, the female is chased and circled with sometimes violent bites in her extremities and rams against the shell. During copulation, the males ride on and sometimes cling to the female's shell. Due to the possibility of storing seeds, the female remains capable of fertilization for several years after a successful copulation without having to copulate again, which increases the success of the turtles in colonizing new habitats, e.g. B. the Galapagos Islands , could explain.

The mating season for species from the temperate climate zone is predominantly in autumn and spring, whereas tropical species tend to be based on rainy seasons and humidity. The egg laying ( oviposition ) takes place a few weeks after fertilization and occurs in all species on land. In harmony with the seasons, the pregnant female looks for a place suitable for leisure activities, for which she often accepts long, dangerous hikes. It pays attention to the location of the square in the sun, the nature of the ground, flood protection and probably other factors. Once selected, this egg-laying site is usually retained for many years. The female digs a deep, often pear-shaped pit with her hind legs, carefully lays the eggs in and carefully closes the pit again so that no nest predators are attracted. Most female turtles leave the eggs to hatch in the sun. Few turtle species practice a kind of brood care by guarding the nesting site. This includes the brown tortoise , a species from the rear Indian tortoise species . Females of this species scrape together a nest of leaves, sand and grass with their forelegs, which has a diameter of 1 to 2.50 meters and is between 20 and 50 centimeters high. In the middle of the pile, the female digs the nesting pit with her head. She then guards the clutch for a period of 2 to 20 days. Sometimes she lies down directly on the nesting pit. However, it also defends its nesting pit against predators by biting or trying to push the predator away from the nesting pit.

The eggs differ greatly in shape, size and texture in the various species. In snake neck turtles, mud turtles, softshell turtles, most tortoises with the exception of the genus Manouria and in many old world pond turtles, e.g. B. in the hinge turtle and American terrapin, they are surrounded by a hard calcareous shell like birds. However, sea turtles, leatherback turtles and alligator turtles only cover their eggs with a leather-like skin and a protective layer of mucus, which also applies to most pelomede turtles. In the New World pond turtles, all representatives of the Deirochelyinae lay soft-shelled eggs, in the Emydinae the representatives of the genera Actinemys , Emydoidea and Emys have hard-shelled eggs and the other genera have soft-shelled eggs. In contrast to birds, however, the eggs do not have any hail cords on which the yolk is rotatably suspended. This is why turtle eggs must not be turned after the embryonic development has started , otherwise the seedling will die. The number of eggs and clutches per season varies widely, from a single egg, e.g. B. in the smallest tortoise species ( Homopus signatus ), up to 200 eggs in sea turtles.

In the case of some species, the sex is not determined genetically at the time of fertilization, but only determined by the incubation temperature (e.g. in the case of European turtle and tortoise species). In certain temperature ranges, predominantly or even exclusively females or males hatch. This fact has proven to be an advantage in breeding projects to protect the species population. Incubation takes about 50 to 250 days, depending on the species. At the end of the development period, the little turtle fills the egg completely. With hard-shelled eggs, she often scratches the shell with the egg callus on the upper jaw and opens a first window. In some cases, the shell is also opened with one leg. Then the folded belly armor begins to stretch and completely bursts the shell open. After hatching, the small turtles often remain in the nest cavity until the yolk sac has been completely resorbed, until they dig themselves to the surface with a joint effort. In arid areas, this usually happens after a late summer rain, which softens the soil and also promises abundant food for herbivores. At the northern limit of their range, turtle hatchlings often hibernate in the nesting pit and only come to the surface in the following spring. The mother animal does not provide protection or rearing aid in any case, the young are on their own from hatching and are sometimes even a welcome prey for adult conspecifics. Several years pass before sexual maturity. It is not only dependent on the age, but also on the nutritional situation of the animal.

Maximum possible age

Turtles can reach a very old age. The year of birth of the Galápagos giant tortoise ( Geochelone nigra ) Harriet , who lived at the Australia Zoo and died on June 23, 2006, is estimated to be 1830, making her at least 176 years old. American box turtles ( Terrapene ) are believed to be well over 100 years old, and sea ​​turtles (Cheloniidae) are believed to live for 75 years or more. With good care, silver turtles kept as pets can live to be 40 years and older.

One of the oldest individuals was Timothy , a female Moorish tortoise ( Testudo graeca ). The former mascot of the British Navy lived to be 160 years old, although she was probably not properly kept on board a warship for the first 40 years of her life.

In contrast to the potential maximum age, the average life expectancy of most turtle species is under natural conditions, which is usually significantly lower. For the Greek tortoise ( Testudo hermanni ) it is only about 10 years from sexual maturity in nature (Hailey 1990/2000).

Examples of particularly old turtles (according to traditional, mostly not entirely certain information) were:

  • Adwaita (* around 1750 (?); † March 22, 2006), 256 years
  • Tuʻi Malila (* around 1773 or 1777; † May 19, 1965), 188 or 192 years
  • Harriet (* around 1830 - 23 June 2006), 176 years
  • Timothy (around 1844 - April 4, 2004), 160 years old
  • King Faruq's Turtle (Inconsistent information on the date of birth and death)
Sea turtle ( green turtle ) off Hawaii, USA

Size differences

In addition to many species that are only 10 to 50 centimeters tall, such as. B. Representatives of the genera Testudo , Emys and Mauremys , the giant tortoises can also be found on the Galápagos Islands ( Geochelone nigra ) and the Seychelles ( Dipsochelys dussumieri ), which reach a shell length of over one meter. Sea turtles and the almost extinct Hoan Kiem Lake giant soft turtle reach even greater shell lengths. The largest species is the leatherback turtle Dermochelys coriacea with a shell length of up to 250 cm and a weight of 900 kg.

The smallest turtles are the males of the sawn flat turtle Homopus signatus from South Africa with a back shell length of about 7.5 cm on average and a weight of about 70 g.

Size specifications for turtles normally refer to the length of the armor without the head, legs and tail. Measurements are made using a stick measure , i.e. straight along the longitudinal axis with the help of a slide rule and not with the tape measure over the armored arch.

Systematics

External system

Skeleton of Proganochelys quenstedti in the American Museum of Natural History
Live reconstruction of Pappochelys rosinae

The exact systematic position of the turtles within the reptiles is still the subject of scientific controversy. Since the turtles do not have skull windows, they are traditionally placed in the anapsida along with some extinct reptile taxa . They would then probably have emerged from the sister group of the Pareiasauria or from them. On the other hand, some scientists are of the opinion that the turtles have lost the skull windows secondarily and thus belong to the Diapsida . The proponents of this hypothesis disagree on whether the turtles are more closely related to the Archosauria (this includes crocodiles , dinosaurs and birds ) or to the Lepidosauria (lizards and snakes). According to the Archosauria hypothesis, the turtles belong to the Archosauromorpha and would probably be the sister group of the Rhynchosauria . The supporters of the Lepidosauria theory suspect a marine origin of the turtles and see them as a sister group of the Sauropterygia , a group of large marine reptiles from the Mesozoic era , which together with the Lepidosauria form the taxon Lepidosauromorpha .

In 2008 Odontochelys semitestacea was scientifically described , the oldest known turtle. The fossil remains of this sea animal, about 40 centimeters long, were found in the Guizhou Province of China. Odontochelys had teeth in the upper and lower jaw and had no back armor, only a belly armor. The description published in June 2015 by Pappochelys , an original relative of the turtle tribe , further supports the theory that the turtles belong to the Diapsidae. Pappochelys had a completely diapsid skull structure (upper and lower temporal window) and proves that the turtle shell was largely created from pre-existing skeletal elements: the back armor from broadened ribs, the belly armor from fused gastralia ("abdominal ribs").

Internal system

In the following the classification of the turtles according to the Reptile Database is given :

Halsberger tortoises (Cryptodira)

The Halsberger tortoises , which began to develop during the Jurassic 180 million years ago, can retract their heads into their shell. The cervical vertebrae of these animals are specially shaped for this purpose, so that the backbone can curve in an S-shape. Today you are represented by eleven families.

Turn-Neck Turtles (Pleurodira)

The pleurodira that exist with three families today, it is the evolutionarily younger subordination , as it only in the Cretaceous appeared. You cannot retract your head like the Cryptodira, but place it sideways under the shell by means of a horizontal S-shaped movement.

Under the systematics of the turtles , all recent species are shown as well as the extinct genera that are described in the German-language Wikipedia. Here are two cladograms that were created according to morphological or molecular biological aspects and which still differ greatly. Naturally, no fossil groups are represented in the cladogram created using molecular biological methods.

Internal systematics according to morphological aspects according to Sterli, Pol & Laurin, 2013 Internal systematics according to molecular biological aspects according to Crawford u. a., 2014


 Odontochelys †


  Testudinata  

 Meiolania †


  Testudines  
  Pleurodira  
  Pelomedusoidea  

 Pelomedus tortoises (Pelomedusidae)


   

 Podocnemididae



   

 Snake neck turtles (Chelidae)



  Cryptodira  

 Santanachelys †


   
  Chelonioinea  

 Sea turtles (Cheloniidae)


   

 Leatherback turtles (Dermochelyidae)



   

 Big-headed turtle (Platysternidae)


   
  Chelydroidea  

 Alligator turtles (Chelydridae)


   
  Testudinoidea  

 New World pond turtles (Emydidae)


   

 Old World pond turtles (Geoemydidae)


   

 Tortoises (Testudinidae)


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  Kinosternoidea  

 Tabasco tortoises (Dermatemydidae)


   

 Mud turtles (Kinosternidae)



  Trionychoidea  

 Papuan softshell turtles (Carettochelyidae)


   

 Softshell turtles (Trionychidae)












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  Testudines  
  Pleurodira  
  Pelomedusoidea  

 Pelomedus tortoises (Pelomedusidae)


   

 Podocnemididae



   

 Snake neck turtles (Chelidae)



  Cryptodira  
  Trionychia  

 Papuan softshell turtles (Carettochelyidae)


   

 Softshell turtles (Trionychidae)



   
  Durocryptodira  
  Emysternia  

 Big-headed turtle (Platysternidae)


   

 New World pond turtles (Emydidae)



  Testuguria  

 Old World pond turtles (Geoemydidae)


   

 Tortoises (Testudinidae)




  Americhelydia  
  Chelonioidea  

 Sea turtles (Cheloniidae)


   

 Leatherback turtles (Dermochelyidae)



  Chelydroidea  

 Alligator turtles (Chelydridae)


  Kinosternoidea  

 Tabasco tortoises (Dermatemydidae)


   

 Mud turtles (Kinosternidae)








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Endangerment situation and species protection

Human threat

Softshell turtle in a Chinese supermarket

Predators vary greatly depending on the type and age of the turtle. While clutches and hatchlings themselves fall prey to crabs and birds, adult animals have few natural enemies. In the particularly species-rich south of the USA these are z. B. Alligators , but also many other armored lizards regularly prey on turtles, as they can easily break open the shells with their powerful jaws. However, humans are also among the predators of eggs and adult turtles. In many parts of the world, turtles, land and sea turtles have been and are eaten and their nests are gutted. How quickly humans can decimate the turtle population can be shown using the example of the European pond turtle . Still to be found quite frequently in German-speaking countries well into the 19th century, it was fished here as a fasting food almost to the point of complete disappearance. In the meantime it has become so rare in Germany and Austria that it threatens to disappear not only from local waters, but also from society's awareness as an originally indigenous species.

The giant tortoises on the island groups in the Indian and Pacific Oceans were also exterminated or almost wiped out by intensive human reenactment. According to a seafarer's report, groups of 2,000 to 3,000 animals could still be found on Rodriguez Island (Mauritius) around 1700. They were so close together that you could "walk 100 paces over their tanks without setting foot on the ground" (Legaut 1691). The meat is tasty and digestible and the fat tastes better than the best butter in Europe. It is also excellent as a medicine for indigestion and cramps. A century and a half later, a scientific expedition found only a few fragments of armor on this island that had become fragile in the sun, but no more living animals. The ship's crews now covered their needs on the Galapagos Islands, often 500–800 animals per shipload. But many other turtle species are also considered a delicacy and are hunted intensively by humans. Since these are largely caught in the wild and the populations reproduce only slowly due to the late sexual maturity , many species are facing extinction in the wild, for example some species of the genus Cuora . In recent years, the main focus has been on the food markets in Southeast Asia, where turtles have always been offered in large numbers. Around 10 million animals are imported into southern China every year (van Dijk et al. 2001). It is often species that are now so threatened that they would actually be strictly protected by the Washington Convention on Endangered Species . The huge breeding farms in the USA with in some cases over 1 million hatchlings per year and farm (Herrera 1998), as well as the turtle farms that were newly established in China in the 1990s, have not yet been able to sufficiently cover the demand. In addition, these farms have created a new problem. Since exotic-looking turtles fetch a higher price on the markets, there are targeted attempts to breed hybrids . On the one hand, this runs counter to species conservation. On the other hand, since this fact became known, the systematics of the Southeast Asian turtles has been in question. For many species that have only been scientifically described in recent years using animals found in markets and whose exact region of origin is unknown, the question of the validity of this taxon now arises . For some holotypes it has meanwhile been proven that they are hybrids of the genera Chinemys and Cuora .

Keeping pets is the second human use of turtles, which is also thousands of years old. In almost all cultures, turtles, unlike other reptiles, are popular and are kept as pets (play animals). Occasionally they are considered sacred animals, e.g. B. in Babylon 1100 BC And also in ancient Egypt. A two and a half thousand year old Greek vase, a museum piece in the British Museum in London, on the other hand, shows a girl playing with a tortoise, what we consider to be cruel.

The shell of the green turtle provides the tortoise shell
Bangle and earrings made of tortoiseshell (now subject to CITES)

However, the fate of the many baby ear turtles kept in the USA in the 20th century and the European tortoises imported to Central and Northern Europe may have been similar. Before the introduction of the Washington Convention on Endangered Species, the wild populations of European tortoise species suffered a considerable decline due to the demand from European and American animal owners. For Great Britain z. For example, the following import figures are known: After the Second World War, up to 250,000 tortoises were imported into England each year, mainly from a single country, Morocco (Lambert 1981). 80% of them died on the way or during the following year. The same is likely to apply to the other European countries, export and import countries, even if their exports and imports are not precisely recorded in terms of numbers. Even today, tourists from the Mediterranean countries bring considerable numbers of turtle hatchlings with them as holiday souvenirs. In addition to the destruction of the habitat , this represents a further significant burden for the turtle populations, which have now declined significantly.

The former children's toy has now become a serious hobby in German-speaking countries, with numerous clubs, associations and regulars. In Germany's largest herpetological association alone, the DGHT and its subgroup, the AG Tortoise, there are almost 3,000 people interested in tortoises who bred over 6,000 small tortoises in over 70 species in 2004, including around 4,000 individuals of the genus Testudo . Overall, the annual breeding of European tortoises is now estimated at around 10,000 in Germany alone (Schilde, 2005).

The "raw material" turtle shell is another ancient use. The smaller turtle shells were mainly used as jewelry and utensils as a whole. In ancient Greece, for example, lyres with a body made from a turtle shell were made. This includes the lyre often depicted on clay pots . Some African string instruments have sound boxes made from turtle shells covered with animal skin, for example lyres and fiddles in East Africa. Bellows made from turtle shells can be bought in North African bazaars. Of the large sea turtles, especially the smallest species, the hawksbill sea turtle (Eretmochelys imbricata), on the other hand, only the upper horny layers were used, which were detached from the bone shell under the application of heat, often from the living animal. This translucent, heavily patterned tortoiseshell has been used as a material for jewelry, toiletries (combs) and inlay work on furniture since ancient times. According to UNEP, the value of tortoiseshell on the world market is around 5,000 euros per kg, which is why it continues to pose a threat to animals despite a worldwide ban.

Other hazardous situations

But the habitat of many turtle species is also threatened by humans or climate change. Tortoises are considered a pest by farmers in the areas of origin and are killed. Insecticides and herbicides poison the animals or destroy the food source. Roads cut through the habitats and lead to high numbers of victims, whereby pregnant females looking for a suitable nesting place are often affected. Marshes and wetlands are drained for agricultural purposes and industry discharges wastewater into the waters inhabited by turtles. The turtles lose suitable biotopes and their food sources due to environmental pollution. River straightening and canalization result in a loss of places for nesting and sunbathing. The reproduction of sea turtles is made more difficult by the tourist development of beaches suitable for nesting. Clutches are trampled on, hatchlings that burrow to the surface at night use the light to orient themselves in order to find the relatively safe water. Artificial light sources lead to a loss of orientation. Sea turtles get caught in driftnets or swallow pieces of plastic , thinking they are jellyfish . Shipping traffic represents a further danger. An estimated 20,000 animals mutilated by propellers were killed in one of the main breeding areas, Orissa Beach, India. In just 30 years, humans have almost managed to eradicate these marine reptiles (UNEP 2004).

Measures to protect the turtles

Greek tortoise:
"passport photo" required for marketing authorization

An important step towards the protection of turtles, as well as that of other threatened species, was the entry into force of the Washington Convention on the Protection of Species CITES in 1975 , to which almost all countries worldwide have now joined. Since then, imports and exports, but also domestic trade in more and more animal species and products from them, have been strictly monitored in some cases, depending on the level of threat. Endangered and therefore protected animal species require marketing permits with individual identification of the animal either by implanting microchips or by photos of back and abdominal armor. In addition, every private owner is obliged to report the purchase, sale, offspring or death of his animals with the number and species to the authorities, e.g. B. in the particularly frequently kept Greek tortoise. If these laws are violated, there is a risk of high fines, costly confiscation of animals and even imprisonment.

Scientists and committed laypeople in all parts of the world are trying to counteract the long list of threats, but also active species protection projects. The protection and reintroduction of the native pond turtle in Germany, for example, is particularly targeted at the Rhinluch nature conservation station in Brandenburg. With the participation of NABU and a few other donation organizations, field research is carried out here, residual populations and their biotopes are protected, young animals are brought back and released into the wild, and general information is provided for the population.

Another hope is the Turtle Conservation Fund, in which American, Australian and European partners have come together to respond to the so-called turtle crisis in Southeast Asia. Within this association, u. a. the Allwetterzoo Münster a highly regarded offspring project of 15 highly endangered turtle species, z. B. different Cuora species.

Remarkable

McCord's snake-necked turtle :
The neck is about as long as the shell
  • The oldest known turtle died in 2006 at the age of 256 in the Calcutta Zoo , see also Adwaita and Harriet (turtle) .
  • The Lonesome George , who was born around 1920 and died in June 2012, was considered to be the last representative of its subspecies, a giant tortoise from the Galapagos, for which a mating opportunity was intensively sought .
  • The leatherback turtle ( Dermochelys coriacea ) is the largest turtle and at the same time the only one without a solid bone shell. Rather, it has a streamlined and flexible, leather-like shell with 5-7 stiffening keels in the longitudinal direction, which represent an adaptation of this sea turtle to its extraordinary diving depth. Although their prey, jellyfish, are mostly surface inhabitants, individual specimens have been found at a depth of over 1000 m. It also colonizes the largest areas, because it roams from its tropical breeding areas to the cold waters of the North Atlantic. This is made possible by their ability, similar to dinosaurs and later warm-blooded animals, to keep their body temperature up to 10 ° C and possibly even more above the ambient temperature (James & Mrosovsky 2004).
  • The fastest turtle is the leatherback turtle with 35 km / h ( Guinness Book of Records 1992), the slowest turtle is the genus Gopherus with 0.21-0.48 km / h (National Geographic, 1999).
Green turtle
  • The green turtle ( Chelonia mydas ), which sometimes only reaches sexual maturity at the age of 50, has the slowest youth growth . During dives, she can lower her heart rate down to a few beats per hour and so stay underwater for up to five hours.
  • The throat-necked snake-necked turtle ( Chelodina rugosa or Chelodina oblonga ) is the only type of turtle to lay its eggs in the mud under water. The development of the embryos only begins after the water has dried up and the eggs are no longer covered by the water.
  • In commentary fights of the male Galápagos giant tortoises ( Geochelone nigra ), the winner is the one who can stretch the neck the highest.
  • In 456 BC According to legend , the Greek playwright Aeschylus was killed by a turtle that an eagle dropped on his head. Eagles prey on turtles by trying to break their shell by falling on a stone.
  • Testudo , the turtle formation, is a Roman military tactic.
  • Since 1990 "World Turtle Day" has been celebrated on May 23rd.

Diseases

Back shell fracture in an areole flat turtle with clear dislocation of the nuchal and the first neural

Shell fractures occur from predators or other trauma. In egg deficiency, an egg is stuck in the ovary or cloaca. The Hexamitiasis is triggered flagellate disease of the digestive tract.

mythology

In the ancient cosmogonies of many Asian peoples, the earth drifts as a round surface on the primordial sea. In order not to sink and to remain calmly in position, a carrier is needed to support the earth. In any case this is an animal and very often a turtle. The starting point for many Asian myths of origin is the Indian idea of ​​the god Vishnu , who lies on the world serpent Ananta-Shesha at the bottom of the ocean and guards creation. In his second incarnation he himself transforms into the turtle Kurma , which serves as the basis for the world axis formed by the mountain Mandara. While the ocean of milk is whisking , gods and demons fight against each other by turning a whisk on the turtle's back, creating a series of divine beings and precious objects.

With the spread of Buddhism , the cosmic turtle made its way to Tibet , China and further north- central Asia . With the Mongols , a golden turtle carries the central world mountain. The creator god Ochirvani (he corresponds to the Bodhisattva Vajrapani ) and his servant Tsagan-Schukuty belong to the Buddhist saga of Central Asia . When they both came down from the sky, they saw a turtle diving in the water. The servant caught the turtle and floated it belly up on the water. Ochirvani lay down on her stomach and instructed his companion to fetch earth from the seabed. They sprinkled this earth on the turtle and finally fell asleep. A little later - the new earth was still very small - the devil came by and wanted to pull the earth and the sleeping people into the sea. Immediately the earth grew so fast that the fleeing devil hardly had time to save himself. Since then, the turtle has been invisible under the water level.

With the Kalmyks, who are also Buddhist , the Bodhisattva Manjushri transforms into a large turtle that lies on its back and holds the earth above the surface of the water. If the turtle moves a toe, there will be an earthquake. When the earth shakes with the Buryats and Tungus , the animal trembles with fatigue. At first the Buryat tortoise looked motionless at the water until the creator god turned it around and built the earth on its belly.

Some North American Indians also know similar myths of origin . The Sioux tell of a turtle with mud in its mouth and a water bird with grass in its beak, who swam together on the primeval sea. They mixed the two together, put it on the turtle's back and created the earth. In the Wyandot Creation, a turtle emerged from the water, which one after the other sent a few animals to the sea floor to fetch mud, until the fish finally succeeded. On the turtle's back, the mud turned into earth.

On numerous Polynesian islands, petroglyphs depict turtles individually or in groups. When interpreting the images, it is often unclear whether they were made for religious, social or aesthetic reasons. Such a distinction may not have been made. Turtles were of great importance in traditional burial ceremonies in Polynesia, so in the Marquesas they played a role in the transition of the deceased into the world beyond. Because sea turtles are able to rise from great depths of the sea and lay their eggs on land, they seem - transferred into the myth - suitable for establishing a connection between the world on this side and the other. Australian Aborigines know the mythical tale emu and turtle .

In Africa, turtles are considered to be particularly clever animals. In fairy tales they usually gain advantages through a trick and win speed competitions against animals that are significantly larger or faster.

"Divine Turtle". Paintings from 1156 to 1161 from the Chinese Jin Dynasty

The Chinese creator goddess Nuwa created the earth by cutting off a turtle's feet and using them to form the four heavenly pillars in the four directions. In China, the mythical turtle Ao is a symbol of the universe. As sacred animals, turtles swim in pools of water on the grounds of many Buddhist temples and are fed by visitors to ensure happiness and longevity. Due to their long life, they have a reputation for being suitable for divination.

Turtles have rarely found their way into popular Islamic beliefs. In the small Moroccan town of Lalla Takerkoust , wish-fulfilling turtles used to be worshiped by Muslim and Jewish pilgrims in a basin next to a holy grave.

In ancient Greek mythology , Chelone was a virgin who was turned into a turtle. The Greek goddess Urania was occasionally depicted with one foot on a turtle, which shows her connection to Aphrodite , whose attribute is the turtle, among other things. Together with Apollon , Hermes was considered the mythical inventor of the lyre for the Greeks . Hermes hollowed out the turtle, attached two reeds and a crossbar to it, pulled seven strings of sheep intestine over the structure and began making divine music.

The fantasy writer Terry Pratchett takes up the Indian myth in his Discworld cycle: The Discworld is carried by four elephants who stand on the back of the star turtle Great A'Tuin (in the original Great A'Tuin ), which through the universe is swimming.

See also

literature

General literature and field studies:

  • D. Alderton: Turtles and Tortoises of the World. New York 1988, ISBN 0-8160-1733-6 .
  • J. Cann: Australian Freshwater Turtles. Beaumont Publishing, Singapore 1998.
  • CH Ernst, RW Barbour: Turtles of the World. New York City 1992, ISBN 1-56098-212-8 .
  • CH Ernst, RGM Altenburg, RW Barbour: Turtles of the World. Win / MAC CD, 1999, ISBN 3-540-14547-8 .
  • CH Ernst, JE Lovich, RW Barbour: Turtles of the United States and Canada. New York 2000, ISBN 1-56098-823-1 .
  • U. Fritz: Handbook of the reptiles and amphibians in Europe. Aula Verlag, Wiebelsheim 2001/2005.
    Volume 3 / 3A: Tortoises (Testudines) I, Bataguridae, Testudinidae, Emydidae. ISBN 3-89104-004-0 .
    Volume 3 / 3B: Turtles (Testudines) II, sea turtles. ISBN 3-89104-654-5 .
  • MW Klemens: Turtle Conservation. Washington, London 2000, ISBN 1-56098-372-8 .
  • FJ Obst: The world of the turtles. Hohenwarsleben 1985, ISBN 3-275-00855-2 .
  • PCH Pritchard, P. Trebbau: Turtles of Venezuela. Society for the Study of Amphibians and Reptiles. Oxford, Ohio 1984.
  • Manfred Rogner: Tortoises - biology, keeping, reproduction. Eugen Ulmer KG, Stuttgart 2008, ISBN 978-3-8001-5440-1 .
  • DG Senn: A natural history of the turtles. Bottmingen / Switzerland 1992.
  • H. Vetter: Turtles of the World - turtles of the world. Frankfurt am Main 2004.

Pet keeping guide:

Turtle Magazines:

Individual evidence

  1. ↑ The ReptileDatabase: Species Numbers (as of Aug 2014)
  2. ↑ a b Tatsuya Hirasawa, Hiroshi Nagashima, Shigeru Kuratani: The endoskeletal origin of the turtle carapace. Nature Communications 4, Article number: 2107, doi: 10.1038 / ncomms3107 , July 9, 2013, accessed July 9, 2013 .
  3. ↑ Dominik Müller: Mediterranean tortoises - biology, husbandry, reproduction, disease.
  4. ↑ Secret of the origin of the turtle shell revealed. In: The Standard. July 9, 2013, accessed July 9, 2013 .
  5. ^ Press Release: The secret of the turtle shell. Riken, July 10, 2013, accessed July 9, 2013 .
  6. ^ The mysterious language of the turtles , orf.at, July 23, 2016, accessed on July 23, 2016.
  7. ↑ a b Chun Li, Xiao-Chun Wu, Olivier Rieppel, Li-Ting Wang, Li-Jun Zhao: An ancestral turtle from the Late Triassic of southwestern China. In: Nature. Volume 456, 2008, pp. 497-501, doi: 10.1038 / nature07533
  8. ^ Walter G. Joyce, Márton Rabi, James M. Clark and Xing Xu: A toothed turtle from the Late Jurassic of China and the global biogeographic history of turtles. In: BMC Evolutionary Biology. Online publication from October 28, 2016, 1616: 236, doi: 10.1186 / s12862-016-0762-5
  9. ^ Winnie Achilles and Franz-Viktor Salomon: Anatomy of the tortoises. In: Franz-Viktor Salomon et al. (Ed.): Anatomy for veterinary medicine. Enke Stuttgart. 3rd ext. Edition 2015, ISBN 978-3-8304-1288-5 , p. 838.
  10. ↑ Manfred Rogner: Tortoises - biology, keeping, reproduction. Eugen Ulmer, Stuttgart 2008, ISBN 978-3-8001-5440-1 , p. 89.
  11. ↑ University of Michigan website
  12. ↑ Petra Kölle: The turtle: pet and patient. Enke Verlag, Stuttgart 2008, ISBN 978-3-8304-1066-9 , p. 66.
  13. ↑ Caroline Maria Hartmann: Investigations into the composition of reptile eggs. Veterinary Faculty, Ludwig Maximilians University, 2009. (PDF; 6.559 kB)
  14. ↑ Michael SY Lee: Molecules, morphology, and the monophyly of diapsid reptiles. ( Memento of the original from October 10, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / dpc.uba.uva.nl
  15. ^ RR Schoch, HD Sues: A Middle Triassic stem-turtle and the evolution of the turtle body plan. In: Nature . 2015. doi: 10.1038 / nature14472 .
  16. ^ Fritz Uwe, Peter Havas: Checklist of the Chelonians of the World. 2007. (PDF; 925 kB) compiled on behalf of CITES
  17. ^ The Reptile Database
  18. ↑ Juliana Sterli, Diego Pol, Michel Laurin: Incorporating phylogenetic uncertainty on phylogeny-based palaeontological dating and the timing of turtle diversification. In: Cladistics. 29 (3), 2013, p. 233. doi: 10.1111 / j.1096-0031.2012.00425.x
  19. ↑ Nicholas G. Crawford, James F. Parham, Anna B. Sellas, Brant C. Faircloth, Travis C. Glenn, Theodore J. Papenfuss, James B. Henderson, Madison H. Hansen, W. Brian Simison: A phylogenomic analysis of turtles. In: Molecular Phylogenetics and Evolution. November 2014. doi: 10.1016 / j.ympev.2014.10.021
  20. ^ Report on the allegedly oldest turtle
  21. ↑ Relatives of "Lonesome George" appeared. Spiegel Online, November 22, 2012, accessed April 27, 2016 .
  22. ↑ Rod Kennett, Damien A. Fordham, Erica Alacs, Ben Corey & Arthur Georges: Chelodina oblonga Gray 1841 - Northern Snake-Necked Turtle Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN / SSC Tortoise and Freshwater Turtle Specialist Group . Chelonian Research Monographs No. 5 doi : 10.3854 / crm.5.077.oblonga.v1.2014 ( ISSN  1088-7105 ), February 28, 2014 (English).
  23. ↑ Celebrate World Turtle Day from humanesociety.org.Retrieved November 27, 2015.
  24. ↑ Uno Harva : The religious ideas of the Altaic peoples. (= FF Communications. No 125). Suomalainen Tiedeakatemia, Helsinki 1938, pp. 27f, 99f.
  25. ↑ Barry Rolett: The interpretation of Polynesian petroglyphs. In: Patrick Vinton Kirch (Ed.): Island Societies: Archaeological Approaches to Evolution and Transformation (New Directions in Archeology). Cambridge University Press, Cambridge 1986, ISBN 0-521-30189-0 , pp. 86f.
  26. ↑ Pierre Grimal: Myths of the Peoples. Volume 2: Persians - Indians - Japanese - Chinese. Fischer, Frankfurt am Main 1977, p. 291.
  27. ^ Edward Westermarck : Ritual and Belief in Morocco. Volume 1, Macmillan and Co., London 1926, pp. 86, 229.
  28. ↑ Karl Kerényi : The mythology of the Greeks. Volume 1. The stories of gods and mankind. Dtv, Munich 1977, p. 130.

Web links

Commons : Turtles (Testudines)  - Collection of images, videos and audio files
Wiktionary: turtle  - explanations of meanings, word origins, synonyms, translations

Species conservation projects and reptile sanctuary:

Turtle communities and associations:

Scientific turtle sites:

This version was added to the list of articles worth reading on August 29, 2005 .