grass snake

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grass snake
2017.07.17.-21-Tiefer See or Grubensee-Storkow (Mark) - grass snake.jpg

Grass snake ( Natrix natrix )

Systematics
Subordination : Snakes (serpentes)
Superfamily : Adder-like and viper-like (Colubroidea)
Family : Adders (Colubridae)
Subfamily : Water snakes (Natricinae)
Genre : European water snakes ( Natrix )
Type : grass snake
Scientific name
Natrix natrix
( Linnaeus , 1758)

The grass snake ( Natrix natrix ) is a species of snake from the family of snakes (Colubridae). It is distributed with several subspecies in large parts of Europe and Asia and occurs relic-like in parts of North Africa . The species mostly lives near bodies of water and feeds mainly on amphibians . Like the other species of the adder ( native to Central Europe), the grass snake is completely harmless to humans.

Origin of name

The name "grass snake" is supposed to refer to the "neck ring" that is formed by the two distinctive patches on the neck. The ability of the animals to curl themselves in very strongly is another possible explanation. Older names that are no longer in use today were swimming snake, water snake, house snake, kuk and schnake (cf. English snake ).

features

Head section of a grass snake with typical markings on the back of the head

In Germany, male grass snakes reach an average total length of 75 cm, females are significantly longer at 85–152 cm. However, females rarely reach lengths of more than 110 cm.

There are two yellow to orange, crescent-shaped spots on the back of the head. There are often four to six rows of small black spots on the mostly gray, sometimes brownish or greenish upper side.

Black snakes occur, they can be recognized by typical features of the scaling and signage: The back scales of the grass snake are keeled (in contrast to those of the similar looking Aesculapian snake ), the shield in front of the eye ( preoculars ) is undivided. The head is covered with large shields at the top and is distinctly (sometimes barely pronounced) from the neck or trunk. The pupils are round.

Own kind of barn snake

The barn grass snake ( N. helvetica , no longer a subspecies of the grass snake since 2017) living in southwest Germany has a row of transverse spots ("bars") on each side of the body. Their neck spots are often paler than in the nominate form N. n. Natrix found in the rest of Germany .

distribution

Distribution area of ​​the grass snake

The range of the grass snake covers almost the entire European continent; in Asia it extends to southern Siberia and the Middle East , in northwest Africa there are relict-like occurrences. In Europe the grass snake is only absent on a few islands and in Ireland . In the Alps it can be found up to 2000 m, sometimes even higher. The northern edge of the distribution area runs through England and Wales via Sweden , Norway , Finland to the north coasts of Lake Ladoga and Onega in the European part of Russia . Outside Europe, the distribution area extends to the Burhat part of Mongolia about 200 km east of Lake Baikal . The southern border runs through northwestern Mongolia, north Xinjiang (China), Kazakhstan , Turkmenistan , northern Iran to Syria and probably northern Lebanon .

Habitats

Swimming grass snake

Grass snakes inhabit a very wide range of open to semi-open habitats . These are characterized by the presence of bodies of water and biotope mosaics with diverse vegetation structures. Dry winter quarters, egg-laying and sunbathing areas as well as hunting areas for the different age groups are sometimes close to each other. Sometimes the queues have to cover greater distances (≫ 1 km) over the course of the year. In the latter cases (as with some amphibians ), separate wetlands (e.g. swamps, floodplains) and rural habitats (forests and their edges, gardens, etc.) can often be identified in the overall habitat.

Typical sites are streams, rivers, ditch systems, ponds and lakes, wet meadows, moors, swamps and their respective surroundings. Grass snakes are also regularly observed in deciduous and pine forests, on railway embankments, on natural (mountainous) and artificial (heaps) slopes, parks and gardens.

Way of life

Grass snake in spring

Grass snakes are diurnal animals. They regulate their body temperature through their behavior by looking for suitable temperature-controlled areas such as sun and shade or the water. In addition, they can selectively enlarge their body surface (flattening out when sunbathing) or reduce it (rolling up in a cool environment) in order to influence the heat exchange with the environment. Structured habitats that offer many different temperatures are important for effective thermoregulation . Grass snakes spend times of unfavorable outdoor conditions (midday heat, winter) in protected roosts.

In Central Europe, wintering usually ends in March or April. After a phase of intense sunshine, the mating season begins around the end of April, and spring moulting has often already taken place. Eggs are laid during the summer, hatching from late July to autumn.

With "normal" weather conditions, the winter quarters are usually visited between the end of September and mid-October. Buildings of small mammals, cavities in the ground, in rocks or trees as well as in masonry, heaps of organic materials (compost, manure, straw, etc.) or stones serve as winter quarters. In the neighborhood, the snakes sometimes switch between soil layers of different depths and thus react to changes in the outside temperature.

nutrition

Grass snake eating a pond newt
Grass snake when hunting in a garden pond

Grass snakes mainly feed on amphibians . In some places the common toad is the most important prey animal, elsewhere frogs , especially brown frogs , form the basis of food. Even small mammals , fish and birds as well as lizards and invertebrates are eaten again and again. The size of the adder also increases the size of its prey: young snakes mainly eat newts , young frogs and smaller tadpoles , while large female grass snakes feed mainly on the large female common toad. Larger frogs are often grabbed by the snakes first by one, then the other hind leg and gradually swallowed down. The front legs are folded forward as easily as possible - if this does not succeed, they too are twisted piece by piece towards the head. The prey is recognized optically based on its movements and in particular through its smell, which is transmitted to the Jacobson organ when it is licked .

Reproduction and development

Mating group
Grass snakes mating
Lay in compost

Most pairings take place between late April and late May. The males are likely to be attracted by the sex pheromones of the females, sometimes more than 20 males woo a female. There are no fights between the competitors. The males try to snuggle up to the female with twitching movements. If this foreplay is successful, the male's tail wraps around the female's rear end, pressing his cloaca against hers . A hemipenis penetrates the cloaca and swells so much that it cannot be withdrawn at first. In the event of disturbances, the smaller partner (usually the male) is therefore dragged along by the fleeing animal. The copulation can last for several hours.

The eggs are laid mainly from late June to early August. Whenever possible, the females lay the eggs in substrates in which rotting organic material releases heat, e.g. B. dung, compost and sawdust heaps, rotting tree stumps, rushes and reeds. Sometimes more than a thousand eggs were found that had been laid in close proximity by different females.

A single clutch often contains 10-30 eggs. The egg length is usually between 23–40 mm and the width 13–20 mm. The mass is often between 4.5 and 5.5 g. The incubation period can be as little as 30–33 days at temperatures of 28–30 ° C, but can extend to ten weeks or more under unfavorable conditions. Accordingly, the young snakes usually hatch between the end of July and the end of September.

Escape and defense behavior

Grass snakes are very shy and try to flee when disturbed. If it is not possible to escape, make your body appear larger (by inflating or flattening it); the front body can be straightened or bent. Rolling up of the snakes and pendulum movements were also observed as a defense. This is followed by hissing and head butts (sham bites) in the direction of the attacker. Real bites are extremely rare and are not threatening to humans or pets. Occasionally, in addition to obvious allergic reactions, acute swelling and discoloration of bitten areas that are not related to an allergic reaction have been reported in humans. They are probably related to the secretions of Duvernoy's glands , but no pain occurred.

If they are held, grass snakes try to free themselves by violent winds, an evacuation of the strongly smelly secretion of the postanal glands occurs regularly. It is not uncommon to observe dead spots (akinesia / thanatosis ). The completely flaccid grass snake lies on its back with its mouth open, and sometimes some blood even comes out of its mouth.

Natrix n. Natrix , the nominate form of the grass snake

Relationships and subspecies

Barring snake

According to current knowledge, the genus Natrix comprises five to six species. In addition to the grass snake type ( N. natrix ), the dice snake ( N. tessellata ) and the viper snake ( N. maura ) have been recognized for a long time . The Iberian grass snake ( N. astreptophora ) was long considered a subspecies of the grass snake , but received species status at the beginning of 2016 because it can be genetically and morphologically clearly differentiated from the grass snake and hybrids are very rare. The barn grass snake ( Natrix helvetica ) living west of the Rhine was recognized as a separate species in 2017.

The species status of Natrix megalocephala (large-headed grass snake ) is questionable. For all generally recognized species, the intraspecific taxonomy has not been conclusively clarified.

On the basis of phenotypic characteristics, 14 subspecies of N. natrix were initially described, of which only three could be confirmed by morphological analyzes and can be brought into agreement with the clades determined by DNA analyzes . These are:

  • the nominate form Natrix n. natrix , which occurs east of the Rhine ,
  • the Sardinian grass snake ( Natrix n. cetti ) in Sardinia and
  • the Corsican grass snake ( Natrix n. corsa ) in Corsica .

Hazard and protection

Grass snakes are common in habitats rich in water, as amphibians are their food source in many places. The grass snake's habitats are being destroyed by draining wetlands, regulating running water, losing floodplain areas and plowing up grassland, draining moors, losing small bodies of water and intensifying pond management . The isolation and segmentation of habitats also poses a danger. Grass snakes are victims of traffic (motor vehicles, including bicycles). Edge biotopes, "wasteland" and forest clearings as living space and connecting habitat element are becoming increasingly rare due to the intensification of agriculture and forestry and land consolidation. Egg-laying places are lost through water regulation and excessive order. In addition, grass snakes are still killed out of hatred or fear of snakes.

In the summer of 2017, the pathogenic fungus Ophidiomyces ophiodiicola (family Onygenaceae ) and the skin disease ( mycosis ) caused by it were detected in grass snakes in Great Britain. In some cases, the infections resulted in the death of the affected snakes. So far, little is known about the fungus, its distribution and its importance for snakes, and it remains to be clarified where the fungus comes from and whether it could pose a threat to snake populations in Europe. Since fungal infections have already been described in many species of snakes from different families, it can be assumed that O. ophiodiicola does not stop at other European species if the conditions are only favorable. Snakes in humid habitats are likely to be more at risk than those who prefer drier habitats.

In Germany the grass snake is particularly protected and must therefore not be harassed, caught or even killed. Protective measures for grass snakes include the regular creation of new egg-laying areas and the creation of amphibious waters; the backup and restoration of (networked) habitats is / would be essential. Protection and species aid programs for grass snakes exist u. a. in Berlin, in Amsterdam and in the Swiss canton of Lucerne.

Legal protection status (selection)

National Red List classifications (selection)

  • Red List Federal Republic of Germany: V - Warning List
  • Red list of Austria: NT (threat of danger)
  • Switzerland's Red List:
Subspecies N. n. Natrix : EN (corresponds to: endangered)

Grass snakes in myths and fairy tales

Grass snakes, which often live near humans and their animals, play a positive role in legends and superstitions. This is in clear contrast to the representation of other snakes or of reptiles in general. Grass snakes as “house snakes” were considered harmless and were often seen with pleasure, or at least tolerated. They had a reputation for bringing good fortune and blessings ( Bavaria , Switzerland, Austria, Vogtland) and protecting the small children and cattle ( Harz ).

The yellow moon spots on the neck were also interpreted as a golden snake crown. Their possession should help to lifelong happiness and increase the belongings. The "robbery of the serpent's crown" and also the giving of the crown by the serpent were the subject of many legends and folk songs. In some fairy tales, the grass snake appears under the name toad ( fairy tale of the toad ).

Even today, the grass snake is considered the patron saint of the inhabitants of the Spreewald , whose cultural heritage includes the legend of the "Snake King". The gable tops of old Spreewald houses often show stylized crossed snake heads wearing a crown.

In fairy tales, the house snakes liked to drink milk, often together with children from a bowl. Their frequent observations in stables (heat, prey animals) led to the assumption that they also milk cows. Grass snakes were worshiped by the Balts and fed with milk. The Zaltones (from Lithuanian žaltys ' grass snake') were snake charmers among the Lithuanians.

literature

The article is based on (as of January 29, 2011, cf. also individual references) and further literature:

  • Klaus Kabisch: The grass snake. (= Neue Brehm-Bücherei. Volume 483). Wittenberg 1978, ISBN 3-89432-830-4 .
  • Rainer Günther, Wolfgang Völkl: Ringelnatter - Natrix natrix Linnaeus, 1758. In: R. Günther (Ed.): Die Amphibien und Reptilien Deutschlands, pp. 666–684, Gustav Fischer, Jena 1996, ISBN 3-437-35016-1 .
  • Klaus Kabisch: grass snake - Natrix natrix (L.). In: W. Böhme (Ed.): Handbook of Reptiles and Amphibians in Europe, Volume 3, Snakes II . Pp. 513-580, Aula Verlag, Wiesbaden 1999, ISBN 978-3-89104-616-6 .
  • Ina Blanke, Adrian Borgula, Thomas Brandt (eds.): Distribution, ecology and protection of grass snakes (Natrix natrix Linnaeus, 1758) (= Mertensiella . Volume 17). DGHT , Rheinbach 2008, ISBN 978-3-9812565-0-5 , ISSN  0934-6643 (published on behalf of the DGHT in cooperation with the coordination office for amphibian and reptile protection in Switzerland).

Web links

Commons : Grass snake ( Natrix natrix )  - album with pictures, videos and audio files
Wiktionary: grass snake  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ a b c d e f g h i Rainer Günther, Wolfgang Völkl: Ringelnatter - Natrix natrix Linnaeus, 1758. In: R. Günther (Ed.): The amphibians and reptiles of Germany. Gustav Fischer, Jena 1996, ISBN 3-437-35016-1 , pp. 666-684.
  2. ↑ Duden: Schnake
  3. ↑ Douglas Harper: snake. Word Origin and History for snake. In: Online Etymology Dictionary. Retrieved June 29, 2016 .
  4. ↑ a b c d e f g h Klaus Kabisch: Grass snake - Natrix natrix (L.). In: W. Böhme (Ed.): Handbuch der Reptilien und Amphibien Europa, Volume 3, Schlangen II. Aula Verlag, Wiesbaden 1999, ISBN 978-3-89104-616-6 , pp. 513-580.
  5. ↑ Distribution map on the IUCN website. Retrieved January 11, 2011.
  6. ^ A b c Ina Blanke, Adrian Borgula, Thomas Brandt (ed.): Distribution, ecology and protection of grass snakes (Natrix natrix Linnaeus, 1758) (= Mertensiella . Volume 17). DGHT , Rheinbach 2008, ISBN 978-3-9812565-0-5 , ISSN  0934-6643 (published on behalf of the DGHT in cooperation with the coordination office for amphibian and reptile protection in Switzerland).
  7. ↑ a b c Dietmar Mertens: Studies on the ecology of grass snakes - results of a radio telemetric field study . In: Ina Blanke et al. (Ed.): Distribution, ecology and protection of grass snakes (Natrix natrix Linnaeus, 1758). Results of the international symposium of the AG Field Herpetology of the DGHT in cooperation with the NABU (= Mertensiella . Volume 17). DGHT , Rheinbach 2008, ISBN 978-3-9812565-0-5 , ISSN  0934-6643 , pp. 151–161 (published on behalf of the DGHT in cooperation with the coordination office for amphibian and reptile protection in Switzerland).
  8. ↑ a b c d e f g h i Klaus Kabisch: The grass snake. (= Die Neue Brehm-Bücherei. Volume 483). Wittenberg 1978, ISBN 3-89432-830-4 .
  9. ^ CJ Reading, JL Davies: Predation by grass snakes (Natrix natrix) at a site in southern England. In: Journal Zoology London 239, 1996, pp. 73-82.
  10. ↑ a b Luca Luiselli, Ernesto Filippi, Massimo Capula: Geographic variation in diet composition of the grass snake (Natrix natrix) along the mainland and in Iceland of italy: the effects of habitat type and interference with potential competitors. In: Herpetological Journal 15, 2005, pp. 221-230.
  11. ↑ Hans-Peter Eckstein: Studies on the ecology of the grass snake. In: Jahrbuch für Feldherpetologie , supplement 4, Duisburg 1993.
  12. ↑ Patrick T. Gregory, Leigh Anne Isaak: Food habits of the grass snake in southeastern England: Is Natrix natrix a generalist predator? In: Journal of Herpetology 38, 2004, pp. 88-95.
  13. ↑ A. Gläßer-Trobisch, D. Trobisch: Bite accident in a grass snake feeding. In: elaphe 16, No. 2, 2008, pp. 59-61.
  14. ↑ a b Felix Pokrant, Carolin Kindler, Martin Ivanov, Marc Cheylan, Philippe Geniez, Wolfgang Böhme & Uwe Fritz (2015): Integrative taxonomy Provides evidence for the species status of the Ibero-Maghrebian grass snake Natrix astreptophora . Biological Journal of the Linnean Society, February, 2016; doi: 10.1111 / bij.12782
  15. ^ Barren grass snake: New snake species registered in Germany. In: ZEIT Online . August 7, 2017. Retrieved August 7, 2017 .
  16. ↑ Carolin Kindler, Maxime Chèvre, Sylvain Ursenbacher, Wolfgang Böhme, Axel Hille, Daniel Jablonski, Melita Vamberger & Uwe Fritz: Hybridization patterns in two contact zones of grass snakes reveal a new Central European snake species. In: Scientific Reports 7, 2016, article number 7378, doi : 10.1038 / s41598-017-07847-9 .
  17. ↑ Lydia HV Franklinos, Jeffrey M. Lorch, Elizabeth Bohuski, Julia Rodriguez-Ramos Fernandez, Owen N. Wright: Emerging fungal pathogen Ophidiomyces ophiodiicola in wild European snakes . In: Scientific Reports . tape 7 , no. 1 , June 19, 2017, ISSN  2045-2322 , doi : 10.1038 / s41598-017-03352-1 ( nature.com [accessed October 30, 2017]).
  18. ↑ The fungus Ophidiomyces ophiodiicola in snakes in Europe - a new fungal disease of the skin in grass snakes and Co..Retrieved on October 30, 2017 .
  19. ↑ Philipp Berg: A snake mushroom on the advance in North America and Europe . In: Terraria / Elaphe . No. 69 , 2018, ISSN  1613-1398 , p. 70-77 .
  20. ↑ grass snake at www.wisia.de
  21. ↑ www.amphibienschutz.de: Online overview .
  22. ↑ www.amphibienschutz.de: Red List Austria (2005) (accessed January 29, 2011).
  23. ^ Lutz Röhrich: Collected writings on folk song and folk ballad research. Waxmann, Münster 2002, ISBN 978-3-8309-1213-2 .
  24. ↑ Grass snake in Spreewald Marketing. (Retrieved January 19, 2011).
  25. ↑ The legend of the serpent king (accessed August 5, 2019).