Lizard snakes
| Lizard snakes | ||||||||||||
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Western lizard snake ( Malpolon monspessulanus ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Malpolon | ||||||||||||
| Fitzinger , 1826 |
The lizard snakes ( Malpolon ) belong to the superfamily of the snake and viper-like (Colubroidae). The genus was introduced in 1826 by the Austrian zoologist Leopold Fitzinger . It consists of two species, the western lizard snake ( Malpolon monspessulanus ) in southern France, Iberia and north-west Africa and the eastern lizard snake ( M. insignitus ), which is distributed in the eastern Mediterranean, across North Africa to the Caucasus.
features
The lizard snakes are large and slender. Adult males usually measure between 130 and 150 cm, females between 90 and 110 cm. In rare cases, old males can grow to a length of 2 meters, and according to some dubious information, even up to 2.5 meters. Females hardly reach more than 130 cm. The head is slim but quite high; it looks angular and hardly separates itself from the body when viewed from above. The eyes are large and have a round pupil. The scales are smooth or - especially on the back - slightly concave, which gives the snake a dull appearance. Around the middle of the body the species has 17 to 19 dorsal rows of scales. The forehead shield (frontal) is very narrow, there are usually eight, rarely nine upper lip shields (supralabialia), two rein shields (lorealia), one forehead shield (praeoculare) and two to three rear eye shields (postocularia). The basic color is in various gray and gray-brown tones to olive or gray-olive. The belly is gray-white to yellowish and darkly spotted. The species shows a clear sexual dimorphism : the males are significantly larger, more massive and completely differently drawn. The lizard snakes have elongated fangs in the back of the upper jaw, which are furrowed on the edge and are connected to a poison gland . Therefore it is classified in the non- monophyletic group of snakes .
There is a possibility of confusion between the lizard snakes and the moila snake ( Rhagerhis moilensis ). They differ among other things in terms of the smaller size of the Moilanatter and the less pronounced canthus .
distribution
The distribution area of the lizard snakes extends over the Iberian Peninsula, southern France, north-western Italy (isolated populations), the east of the Mediterranean Balkans from Trieste to Burgas and Istanbul, Western Asia and North Africa. The snakes can also be found on some islands in the Mediterranean . The preferred habitats are dry and sparsely overgrown, rocky terrain (maquis), mountain slopes, wasteland and hill country, river valleys and cultivated land such as overgrown gardens and vineyards as well as arable land. It penetrates mountainous areas at heights of almost 2000 m .
Way of life
The genus is predominantly ground-dwelling. Lizard snakes are very observant or shy, day to dusk active snakes. They use the early morning sun to warm up. The males in particular often fall victim to road traffic because they are careless and eager to hike during the mating season. In the climatically moderate distribution area, the lizard snakes hibernate for several months, which they interrupt on sunny, mild days.
nutrition
The lizard snakes have a comparatively large food spectrum. Their prey includes lizards , especially lizards , other snakes , small mammals such as rodents and birds , preferably ground and cave breeders. In addition, young lizard snakes also prey on larger insects . Larger and defensive prey animals are held and by chewing movements poison is injected with the rear furrow teeth in order to stun and kill them. Smaller animals are often gobbled down alive.
Social behavior
Lizard snakes males are territorial . In special nasal glands they produce a clear secretion that contains a fragrance and is brushed onto the ventral shields (belly shields) with a characteristic cleaning behavior. During the act of mating, the corresponding female absorbs the fragrance in pits of the dorsal scales (back scales). This marks the female for a permanent partnership. The male defends his female and, in addition to its own needs, also hunts prey that is left to the female. Other males use a "satellite strategy": They live in the couple's territory, also get the secretion of the dominant male and take his place when he dies.
Reproduction
The lizard snakes belong to the group of oviparous snakes, so they lay eggs with a firm shell. The mating of the females takes place during the mating season between April and June. Eggs are laid around July to August. The size of the clutch is between 4 and 20 eggs, depending on the state of health and size of the mother. The clutch is laid out under leaf litter, in damp earth or in crevices in the wall. The young snakes hatch towards the end of September or beginning of October. No brood care is observed in the lizard snakes.
Poison
Because of the very shy way of life of the snake, humans hardly ever have bite accidents; Farmers represent a risk group, because they are the most likely to come across lizard snakes unexpectedly, for example in stables or grain stores. Basically, the lizard snakes defend themselves with hissing, mock attacks and snapping. Bite accidents only occur when the animal is deliberately grabbed, which triggers holding bites as a defense in which the snake tries to chew the poison. However, no deaths or life-threatening poisoning are known.
Poisonous effect
Many bites are dry , that is, without injection of venom. Accordingly, they usually run without symptoms . In particular , the poison shows neurotoxic components that attack the nervous system . The poisoning is mostly only associated with local symptoms; pain, swelling of the lymph nodes and lymphangitis ( inflammation of the lymph vessels of the skin and subcutaneous fatty tissue ) can occur. Effects on the central nervous system have been observed in at least one bite victim . Over 48 hours of persistent breathing problems, paralysis of the eyelids ( ptosis ) and swallowing disorders in connection with pain in the sternum and upper abdominal area were found.
Therapy of a poison bite
As for most false snakes, no special antivenin (counter-serum) is available for the lizard snakes. Because of the lack of experience, every bite should be taken seriously and treated medically. Inpatient admission to a hospital for monitoring over 24 hours is also advisable.
Hazard and protection
The western lizard snake is not endangered and is listed in the IUCN Red List as "least concern" (not endangered). It is listed in Appendix III of the Bern Convention .
swell
Individual evidence
- ↑ The IUCN Red List of Threatened Species: Malpolon monspessulanus (as of July 29, 2009)
literature
- Ulrich Gruber: The snakes of Europe. Franckh'sche Verlagsbuchhandlung, Stuttgart 1989, ISBN 3-440-05753-4 , p. 165.
- Mark O'Shea: Venomous snakes. All species in the world in their habitats. Franckh-Kosmos Verlag, Stuttgart 2006, ISBN 3-440-10619-5 .
- Chris Mattison: Encyclopedia of Snakes. blv Verlag, ISBN 978-3-8354-0360-4 .
- Ulrich Gruber: Amphibians and Reptiles. Franckh Kosmos Verlag, ISBN 978-3-440-09212-5 .
- Wolfgang Böhme: Caenophidia, adder-like and otter-like. In: Wilfried Westheide, Reinhard Rieger (Ed.): Special Zoology. Part 2: vertebrates or skulls. Gustav Fischer, Stuttgart 2004, ISBN 3-8274-0900-4 , pp. 378-380.
- Dieter Schmidt: The genera of the subfamily Boiginae. In: Dieter Schmidt: Trugnattern. bede, Ruhmannsfelden 1998, ISBN 3-931792-89-7 , pp. 71-87.
- W. Reinhard, Z. Vogel: The snakes. In: Bernhard Grzimek (Hrsg.): Grzimeks Tierleben Kriechtiere. Bechtermünz, Augsburg 2000, ISBN 3-8289-1603-1 (unchanged reprint of the original edition from 1979/80), pp. 390-423.
