Smooth snake

Description

Smooth snakes are delicate, slender snakes; they reach a body length of 60 to 75, occasionally 80 cm (in isolated cases specimens of about 90 cm total length have been observed). There is no significant difference in size between the sexes. The tail accounts for 12 to 25 % of the total length. It tapers evenly and ends pointedly. Body weights of average animals range from 50 to 80 g; weights over 100 g are rarely reported. Higher weights are attained by large pregnant females. The body is cylindrical (roundish in cross-section), with the anterior and posterior sections having smaller diameters than the middle. The transition from the narrower neck to the broader head is smooth. The top of the head is flattened, and the sides and tip of the snout are rounded. The eyes are relatively small with round pupils (an important distinguishing feature from the European adder); the iris is brownish. A longitudinal furrow runs between the eye and the nostril. There are 12 to 16 teeth in the upper jaw, which increase slightly in length toward the throat, while the same number of lower teeth are all similar in length.

Regarding the head and body scaling, the following characteristics are to be mentioned: There are seven upper lip shields (supralabialia) and eight to nine lower lip shields (sublabialia) on each side. The rostral shield is large and reaches between the nostrils. In contrast to the Girondian smooth snake, it is wedge-shaped between the internasalia, which gives them a butterfly shape. The nostrils are located centrally in the nasals. The largest shields of the upper head are the two elongate parietalia. The body scales are smooth without keels. Directly behind the head they are rather roundish and small, tailward they become elongated and end pointed. On the tail they have a pentagonal to hexagonal shape, on the sides of the body they are broader than on the back. In the middle of the body, the transverse rows consist of 19 scales each. Ventral bars are present between 150 and 190, tail shield pairs between 40 and 70. The anal shield is usually divided.

The basic coloration of the upperpart is gray, gray-brown, brownish or reddish-brown. Males are dominated by brown to reddish tones, while females are often more gray. However, coloration is not a completely clear differentiator between the sexes (only the protrusion of the hemipenes of males can serve this purpose). On the sides of the head there is a characteristic dark brown stripe, which runs from the nostril over the eye to the corner of the mouth. Often it continues to the side of the neck, from where it changes into small single spots. On the top of the head a heart- or horseshoe-shaped dark spot is noticeable (the "coronet"), which often continues in two longitudinal stripes on the back, to finally dissolve mostly in two (rarely four) rows of spots. Towards the tail these spots become more and more indistinct. Occasionally, the spots may merge into transverse stripes. However, for all the variability of the dorsal spot pattern, the smooth snake does not exhibit a zigzag band like European adders have. However, movements of the snake can create such an impression.

Habitat

The smooth snake is a drought- and heat-loving species that colonizes a fairly wide range of habitat types, depending on the region. While in northern Germany, the Netherlands and southern England, for example, sandy heaths, rough grasslands and dry upland moorland and forest edges are important habitats, in the central European low mountain ranges it is mainly warmth-favored slopes with rough and dry grasslands, scree slopes, dry stone walls and abandoned vineyards. In higher low mountain ranges, in eastern Bavaria or in southern Sweden, sunny forest edges in the vicinity of extensively cultivated meadows, shrub heaths, hedgerows, woodland slopes, rock heaths, semi-shrubby rough grasslands and embankments form the biotope spectrum of the smooth snake. In the alpine region, a variety of open to semi-open habitats in warmth-favorable locations are colonized. In addition, anthropogenic special sites such as railroad embankments and quarries are found everywhere. Occasionally, smooth snakes can also be found at near-natural settlement edges of villages and cities.

Common to all habitats is a mosaic-like, small-scale alternation of open, low-vegetated and partly wood-dominated sites and a high density of small structures and shelters. In the same habitat, there are usually also many lizards (especially sand lizards, regionally also common lizards or common wall lizards) and slow worms. Occasionally, the European adder also occurs syntopically.

The text is a translation of an excerpt from Wikipedia ( (https://de.wikipedia.org/wiki/Schlingnatter). On wikipedia the text is available under a „Creative Commons Attribution/Share Alike“ licence. Status: 26 May 2021