Great-headed grass snake
| Great-headed grass snake | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Great-headed grass snake ( Natrix megalocephala ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Natrix megalocephala | ||||||||||||
| Orlov & Tuniyev , 1987 |
The large-headed grass snake ( Natrix megalocephala ) belongs to the European water snake ( Natrix ) within the family of the adder (Colubridae ). The taxonomic status of this species, described by Russian authors in 1987, is controversial. Possibly it is only a subspecies of the grass snake ( Natrix natrix ), presumably particularly strong specimens of the Siberian grass snake ( Natrix n. Scutata ). Their distribution is limited to the Caucasian region.
features
This snake reaches a body length of 80 to 120 centimeters. It is built relatively sturdy - the relatively large head of the animal is striking. This has enlarged shields with a fine relief pattern on the top, a fore-eye shield (praeoculare), three posterior eye shields (postocularia) and seven to eight upper lip shields (supralabialia). The last three upper lip shields are very large, and the third and fourth touch the edge of the eye. The eyes have a round pupil. The entire back, the flanks and the top of the head are colored uniformly black. The underside of the head, the lower lip shields (sublabials) and some of the upper lip shields are brightly colored. The belly scales (ventral shields) are gray-black and lightly spotted, but purely black towards the tip of the tail. The body scales of the large-headed grass snake are smooth, it has 18 to 19 rows of back scales.
Way of life
The ground-dwelling large-headed grass snake leads a diurnal and shy way of life, but stays in the shade during the day when it is very hot. When threatened, the snake flees into flowing waters and also hides under water. In the lowlands it hibernates for almost four months, in mountainous areas for seven months, from late September to late April. Their range of prey includes tailed amphibians and frogs , and occasionally fish . The large-headed grass snake is oviparous , i.e. laying eggs. The clutch can contain up to 15 comparatively large eggs.
Occurrence
The great-headed grass snake is common within the Caucasus - Black Sea region in Azerbaijan , Georgia , Russia and Turkey . The habitats are riparian forests , light forests close to the water with evergreen undergrowth, forest edges and forest meadows. As a cultural follower , you can also find them on the edges of fields or on tea plantations. In the Caucasus Mountains, the great-headed grass snake penetrates to heights of 1500 meters.
Danger
Natrix megalocephala is generally not very numerous and the population is declining. The main problem is introduced raccoons , which are strong competitors for food , and habitat loss as a result of tourism along the Black Sea coast. The World Conservation Union ( IUCN ) lists the species as "vulnerable", i.e. endangered.
swell
Individual evidence
- ^ Natrix natrix in The Reptile Database ; accessed on August 27, 2018.
- ^ Dieter Glandt: Pocket dictionary of the amphibians and reptiles of Europe. Quelle & Meyer, Wiebelsheim 2010. ISBN 978-3-494-01470-8
- ↑ a b IUCN Red List: Natrix megalocephala
literature
- Ulrich Gruber: The snakes of Europe , Franckh-Kosmos-Verlag, Stuttgart 1989. ISBN 3440057534 .
