Stair snake
| Stair snake | ||||||||||||
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Step snake ( Zamenis scalaris ), Portugal |
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| Scientific name | ||||||||||||
| Zamenis scalaris | ||||||||||||
| ( Schinz , 1822) |
The stair snake ( Zamenis scalaris , Syn . : Rhinechis scalaris , Elaphe scalaris ) is a species of adder that is native to the Iberian Peninsula and southern France. It reaches a body length of 1.0 to 1.60 meters and is easy to distinguish from other species due to its dark longitudinal stripes on the back. It is named after the drawing pattern of the young animals, which appears like a staircase.
features
With an average length of about 1.20 meters, the stair snake is relatively large, and it has a sturdy build with a head only slightly separated from the body. The maximum length is around 1.60 meters; the snakes on Menorca, on the other hand, are smaller and usually stay under a meter in total length. The head is slightly triangular with a pointed snout, the pupils are round. There are seven to nine large scales in front of the eyes, the shields of the upper lip ( supralabials ), the fourth and fifth touching the eyes. There is also a pre-eye shield ( praeoculare ). On the upper side, the animals are yellowish-brown, more rarely they can also be dark or red-brown. What is striking is the drawing on the back, which in the adult animals consists of two strong dark brown longitudinal stripes from the neck to the end of the tail. Between these stripes there are several horizontal stripes, which are particularly pronounced in the young animals and which form the staircase or ladder pattern that gives them their name (in English-speaking countries therefore known as "ladder snake"). These spots are H-shaped and the crossbars fade with age and the number of moults . Overall, the back surface is formed by an average of 27 rows of scales , rarely 25 or 29, with the scales not keeled. The underside of the snakes is lighter yellowish to whitish in color. The young animals have a dark spot on the ventral side, which also fades in the course of development.
distribution and habitat
With the exception of the north, the stair snake lives on the entire Iberian Peninsula , both in Spain and Portugal , as well as in the extreme south of France . It can also be found on the Mediterranean island of Menorca .
Its height distribution ranges from sea level to around 2,200 meters, preferring dry, warm scree areas with high vegetation density . In the more humid mountain areas in Portugal, on the other hand, they are only found up to a maximum height of 900 meters, i.e. only up to the submontane region. For example, it is very common in overgrown vines , in cork oak stands , in hedges and ruins, as well as in fallow arable land and dry pine stands. Overall, however, the snake is not very specialized in the choice of habitat and is similar to the lizard snake ( Malpolon monspessulanus ), but it avoids cool and above all rainy areas. The snake can also be found in the vicinity of dwellings and it is not uncommon for it to penetrate into inhabited buildings.
Way of life
The stair snake is active both during the day and at dusk. The activity maximums during the day vary from region to region in spring and early summer from April to May and June. From May / June, it shifts its activity to dawn and dusk and sometimes into the early hours of the night. During these times, it mainly hunts for small mammals up to the size of small rabbits and birds, which it grabs with its mouth and then strangles with its body. It is relatively aggressive and attacks potential enemies with heavy bites, although it has no snake venom . The young animals in particular hiss as a warning of the attack. It lives primarily on the ground, but can also climb plants or masonry. In strong sunlight and strong winds, the animals seek shelter under stone slabs.
The animals spend the nights in caves in the ground, very often in empty buildings of small mammals. From around October to November the snakes retreat and hibernate for around four to five months.
Reproduction and development
The mating season of the stair snake takes place after the winter dormancy in April to May, whereby the mating usually takes place at night. After the next molt, the females lay clutches of 5 to 25 eggs in the ground, which are left to their own devices. The young snakes hatch after two to three months and at that time have a total length of about 10 to 25 centimeters. They mainly feed on insects such as grasshoppers, as well as small lizards .
Systematics
The stair snake was originally listed in the genus Elaphe , which has been revised. After that it was the only species of the newly created genus Rhinechis , but now it belongs to the genus Zamenis . The species is monotypical, so there are no known subspecies.
Hazard and protection
This species is not particularly endangered because, as a non-poisonous snake, it is not hunted excessively and has no particular attachment to specific habitats. It is one of the species that very often fall victim to road traffic. Regionally, large-scale cultural changes and buildings can endanger their existence. As a European species, the stair snake is listed in Appendix 1, Column 2 of the Federal Species Protection Ordinance and is therefore subject to special species protection. The keeping of the animals must accordingly be reported to the species protection authorities.
literature
- Ulrich Gruber: The snakes in Europe and around the Mediterranean. Franckh'sche Verlagshandlung, Stuttgart 1989, ISBN 3-440-05753-4 .
- Axel Kwet: Reptiles and Amphibians of Europe. Franckh-Kosmos Verlag, Stuttgart 2005, ISBN 3-440-10237-8 .
- Rudolf Malkmus: The amphibians and reptiles of Portugal, Madeira and the Azores. (= Die Neue Brehm-Bücherei. Volume 621). Westarp Sciences, Magdeburg 1995, ISBN 3-89432-440-6 .
Web links
- Zamenis scalaris in The Reptile Database
- Photos of the stair snake on www.herp.it
- Rhinechis scalaris inthe IUCN 2013 Red List of Threatened Species . Posted by: Juan M. Pleguezuelos, Paulo Sá-Sousa, Valentin Pérez-Mellado, Rafael Marquez, Marc Cheylan, Claudia Corti, Iñigo Martínez-Solano, 2009. Retrieved September 15, 2013.
