Dice snake
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Dice snake ( Natrix tessellata ) |
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| ( Laurenti , 1768) |
The dice snake ( Natrix tessellata ) is a non-poisonous, harmless Eurasian snake from the family of the adder (Colubridae) and the genus of the European water snake ( Natrix ). The heat-loving species is extremely rare in Central Europe. She was named " Reptile of the Year 2009".
features
Cube snakes are slender, laterally slightly flattened shape and with a narrow, pointed head. The females become larger than the males and in southeastern Europe they sometimes reach a total length of 130 centimeters; in Germany a maximum of 102 cm was detected. Males, on the other hand, rarely grow longer than 80 cm. The coloring of the top varies - also regionally different - between different gray, brown and olive tones and can appear very light to very dark. As a pattern there are usually four to five rows of mostly square spots after which the snake species is named. These are either arranged alternately or can merge to form longitudinal strips or cross ties. The underside of the animals is colored white to yellow and has a pattern of (blue) black, square, contrasting spots.
Young animals have a lighter basic color and have a strong V-spot on the neck. Otherwise they are more or less vividly spotted like the adult animals.
The eyes of the dice snake have round pupils and an inwardly yellow, unspotted iris; on the outside, it is darkened by brown or black color deposits. The tongue, which ends in two narrow, long tips, is flesh-colored. The dorsal scales are strongly keeled. There is a very wide range of variation in the dandruff features. As a rule, the head area has two to three preocularia (front eye shields), two to five postocularia (rear eye shields), seven to eight supralabials (upper lip shields) and eight to ten sublabials (lower lip shields ). The number of blackish tail shields varies between 54 and 78, with the males having longer tails and correspondingly more tail shields.
From the closely related grass snake , the dice snake-moon bright spots differs among other things by the absence at the back. The viper snake is very similar in appearance and way of life . Its range is in the west, with only a small area in northwestern Italy where both species occur.
distribution
The range of the species is in parts of Central , South and Southeast Europe as well as West and Central Asia . It includes Italy , east and south-east Austria , the entire Balkan Peninsula , the area around the Black Sea and the Caspian Sea and reaches the western edge of China in the east . With the Nile Delta , Africa is also just included. The area has its greatest north-south extension at the level of the Caspian Sea, where it extends from southern Russia and northwestern Kazakhstan in the north to southern Iran in the south.
On the northwestern edge, the distribution area dissolves into disjoint outposts. So exist in Germany autochthonous only three very small, isolated populations on the Rhine tributaries currently Lahn , Mosel and Nahe in the state of Rhineland-Palatinate . In other places, such as on the Middle Rhine between Bingen and Remagen , the natural occurrence of the species has now died out. The dice snake also died out on the Elbe near Meißen in Saxony in the middle of the 20th century, but has apparently been successfully reintroduced there in recent years. In Switzerland , the dice snake occurs naturally only in the south ( Ticino ). However, populations exposed by humans are also present at various lakes in northern Switzerland.
Subspecies
In addition to the nominate form Natrix tessellata tessellata , only one other subspecies has meanwhile been recognized as valid - the Natrix tessellata heinrothi , which occurs on the snake island in the Black Sea . However, their delimiting characteristics are now considered to be insufficiently resilient and the species is therefore currently monotypic (without valid subspecies).
Habitat and way of life
This snake colonizes climatically favorable rivers and lakes in floodplains with high fish stocks. The bank zones should be structured in a natural way and, in addition to herbaceous vegetation, also have open flushing fringes and banks made of gravel or crushed stone. Also important are flat, flow-calmed zones with high levels of solar radiation as well as slopes with dry grass near the shore and rocks, dry stone walls or the like rich in shelters.
In Central Europe, the dice snake is the snake with the strongest attachment to water. She is excellent at swimming and diving, and often spends long hours in shallow water. It only leaves the water for sunbathing, reproduction and wintering. But also to devour bulky prey, which consists almost exclusively of small to medium-sized fish , the animal sometimes goes to the river bank. If it is disturbed, it chokes out the prey again and escapes into the water.
Cube snakes are diurnal with a focus on the morning and afternoon hours. While the morning is used for sunbathing, the foraging takes place in the afternoon. The available range of fish is used. In Germany it was observed that the gudgeon ( Gobio gobio ) is one of the regular prey animals; but various other species of carp fish also make up an essential part of the diet. The prey is either ambushed underwater or actively sought. Then it is grabbed at lightning speed, held in place with the small needle-sharp teeth and finally devoured.
The dice snake's predators are smaller mammals such as rats, muskrats , ermines and weasels, as well as birds such as herons and black-headed gulls . Large predators such as pike and catfish are also believed to be among their predators . An increasingly recognized problem with the German population is the consumption of young snakes by mallards .
When it feels threatened or is caught, the dice snake makes hissing noises. In addition, they can, as the grass snake, a foul-smelling secretion Postanaldrüsen spray and occasionally play dead ( Schreck Rigid ).
The winter quarters on land - frost-proof, sun-exposed crevices and hollows on bank slopes - are usually visited in Rhineland-Palatinate towards the end of September, and in mild weather not until the end of October, and left again in the middle to the end of April. The females appear a little earlier than the males.
Reproduction and Individual Development
(Phenological dates refer to Central Europe.)
The mating season is in the months of May and June (generally two to four weeks after leaving the winter quarters). Several animals can come together in one place and form real “mating balls”. From the beginning of July, eggs are laid at night or in the early morning in places with a loose soil substrate made of sand or humus (also dung heaps). A female lays between 5 and 25 soft-shelled eggs in the ground or under rotten wood. These are oval and 3 to 4 cm long and 2 to 2.5 cm thick. Depending on the ambient temperature, they require an embryonic egg activity of 34 to 50 days and gain 20 to 40 percent in weight during this time (from initially three to eight grams to ten grams and more). Newly hatched snakes are 14 to 24.5 cm in length. The little ones apparently ingest food shortly after the first molt , which occurs about a week after hatching. With an optimal food supply, the young can reach a maximum length of 30 cm before the first winter. Sexual maturity occurs after three and a quarter years with a body length of 50 to 60 cm.
Hazard and protection
The dice snake is legally protected in many countries. Their populations are severely threatened in Central Europe; in Germany the species is one of the rarest vertebrates - there are probably only a few hundred adult specimens left. The stocks collapsed dramatically in the course of the 20th century, mainly as a result of bank expansion measures, river straightening, barrage construction, water pollution and the construction of traffic routes along the banks. But also increasing leisure activities on the river banks, ship traffic (many cuts from ship's propellers!) Or the killing or catching of snakes by anglers, bathing and camping guests as well as animal keepers are a serious danger in already weakened populations. Often there is a shortage suitable and undisturbed egg-laying places or in winter quarters. These are also not infrequently separated from the aquatic habitat by traffic routes. Last but not least, massive flood events can sweep young dice snakes along and drift away. In this context, it is again the man-made landscape changes in river valleys that cause particularly sudden, flow-intensive and high-rise flood waves.
Legal protection status
- Federal Republic of Germany:
"Strictly protected species" (thus also "specially protected species") and "species of community interest" within the meaning of the Federal Nature Conservation Act .
- European Union:
Protected by provisions in the legal and administrative provisions of the member states, by means of which those of the Council Directive 92/43 / EEC of May 21, 1992 on the conservation of natural habitats and wild animals and plants (Habitats Directive) means to implement the directive into national law, which is what makes it valid), Annex IV of which identifies Natrix tessellata as “strictly protected species of community interest”.
National Red List classifications (selection)
- Red List of the Federal Republic of Germany: 1 - critically endangered
- Red list of Austria: EN (corresponds to: highly endangered)
- Red list of Switzerland: EN (corresponds to: highly endangered)
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literature
- Günter Diesener & Josef Reichholf: Amphibians and reptiles. Steinbach's nature guide. Mosaik-Verlag, Munich 1986, ISBN 3-570-01273-5 .
- Michael Gruschwitz: dice snake, Natrix tessellata (Laurenti, 1768). In: Laufer / Fritz / Sowig (ed.): The amphibians and reptiles of Baden-Württemberg. Ulmer Eugen Verlag, Stuttgart 2007, ISBN 3-8001-4385-2 , pp. 687-692.
- Michael Gruschwitz & Rainer Günther: Cube snake, Natrix tessellata (Laurenti, 1768). In: Rainer Günther (Ed.): The amphibians and reptiles of Germany. Gustav Fischer, Jena 1996, ISBN 3-437-35016-1 , pp. 684-699.
- Mebert, Konrad (Eds.): The Dice Snake, Natrix tessellata : Biology, Distribution and Conservation of a Palaearctic Species. Mertensiella 18, Rheinbach 2011, ISBN 978-3-9812565-4-3 , 456 pp.
Web links
- Natrix tessellata in The Reptile Database
- Photos of the dice snake at www.herp.it
- German Society for Herpetology and Terrarium Science V. (DGHT): Reptile of the year 2009: The dice snake. August 2009.
- The dice snake in Austria at www.herpetofauna.at: Species description, distribution and pictures
- Cube snake ( Memento from June 6, 2013 in the Internet Archive )
- Information and photos at www.reptilien-brauchen-freunde.de
- Natrix tessellata inthe IUCN 2013 Red List of Threatened Species . Posted by: Agasyan, A., Avci, A., Tuniyev, B., Isailovic, JC, Lymberakis, P., Andrén, C., Cogalniceanu, D., Wilkinson, J., Ananjeva, N., Üzüm, N ., Orlov, N., Podloucky, R., Tuniyev, S., Kaya, U., Ajtic, R., Vogrin M., Corti, C., Mellado, VP, Sá-Sousa, P., Cheylan, M ., Pleguezuelos, J., Baha El Din, SM, Nettmann, HK, De Haan, CC, Sterijovski, B., Schmidt, B. & Meyer, A., 2009. Retrieved September 19, 2013.
Individual evidence
- ↑ Legal ordinance on the nature reserve "Moselufer between Niederfell and Dieblich" Landkreis Mayen-Koblenz of August 8, 2003 . Ref .: 424 - 1.137.14. Text of the ordinance without maps online in: Landscape Information System of the Rhineland-Palatinate Nature Conservation Administration (LANIS-RLP) . Ministry for the Environment, Energy, Food and Forests Rhineland-Palatinate , p. 4–9, here: § 3, p. 5, accessed and received on August 4, 2016 (PDF file; 197 KiB).
- ↑ In accordance with Section 7 (2) No. 14 of the Federal Nature Conservation Act in conjunction with Annex IV of Council Directive 92/43 / EEC of May 21, 1992 on the conservation of natural habitats and wild animals and plants (Habitats Directive) ( consolidated version of July 1, 2013 , accessed August 8, 2016 ). In: Official Journal of the European Union , L 206 of July 22, 1992, ISSN 0376-9453 , pp. 7-50. Online in: EUR-Lex . Publications Office of the European Union .
- ↑ Pursuant to Section 7 (2) No. 13 of the Federal Nature Conservation Act in conjunction with Annex IV of Council Directive 92/43 / EEC of May 21, 1992 on the conservation of natural habitats and wild animals and plants (FFH Directive) ( consolidated version of July 1, 2013 , accessed August 8, 2016 ). In: Official Journal of the European Union , L 206 of July 22, 1992, ISSN 0376-9453 , pp. 7-50. Online in: EUR-Lex . Publications Office of the European Union .
- ↑ According to § 7 Paragraph 2 No. 10 of the Federal Nature Conservation Act in conjunction with Annex IV of Council Directive 92/43 / EEC of May 21, 1992 on the conservation of natural habitats and wild animals and plants (FFH Directive) ( consolidated version of July 1, 2013 , accessed August 8, 2016 ). In: Official Journal of the European Union , L 206 of July 22, 1992, ISSN 0376-9453 , pp. 7-50. Online in: EUR-Lex . Publications Office of the European Union .
- ^ Taxon information on Natrix tessellata (LAURENTI, 1768) . In: WISIA-online - Scientific Information System for International Species Protection - Species Protection Database of the BfN . Federal Agency for Nature Conservation , accessed and received on August 8, 2016.
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↑ National implementing
measures communicated by the member states regarding: Council Directive 92/43 / EEC of May 21, 1992 on the conservation of natural habitats and wild fauna and flora , accessed on August 8, 2016 ,
as well as
Directive 97 / 62 / EC of the Council of October 27, 1997 on the adaptation of Directive 92/43 / EEC on the conservation of natural habitats and of wild animals and plants to technical and scientific progress , accessed on August 8, 2016 ,
Directive 2006/105 / EC of the Council of November 20, 2006 for the adaptation of Directives 73/239 / EEC, 74/557 / EEC and 2002/83 / EC in the field of the environment on the occasion of the accession of Bulgaria and Romania , accessed on August 8, 2016 and
Directive 2013/17 / EU Council of May 13, 2013 for the adaptation of certain directives in the field of the environment due to the accession of the Republic of Croatia , accessed on August 8, 2016 . Each in: EUR-Lex . Publications Office of the European Union . - ↑ Annex IV of Council Directive 92/43 / EEC of May 21, 1992 on the conservation of natural habitats and of wild fauna and flora in the consolidated version of July 1, 2013 , accessed on August 8, 2016 . In: Official Journal of the European Union , L 206 of July 22, 1992, ISSN 0376-9453 , pp. 7-50. Online in: EUR-Lex . Publications Office of the European Union .
- ↑ Online overview at www.amphibienschutz.de
Forest Lizard (2006) | Common Garlic Toad (2007) | European tree frog (2008) | Dice Snake (2009) | Pond newt (2010) | Wall Lizard (2011) | Common Toad (2012) | Smooth Snake (2013) | Yellow-bellied toad (2014) | European pond turtle (2015) | Fire Salamander (2016) | Slow Worm (2017) | Common Frog (2018) | Mountain Newt (2019)