There are 18 types of snakes in Bulgaria, 5 of them poisonous and only one with a poison able to harm a human. As of 2020 one of them is extinct.
1. Gray Water Snake. The gray water snake is found throughout the whole mediterranean, but avoids mountainous areas. It enters the Black Sea waters.
2. Grass snake. The grass snake, sometimes called the ringed snake or water snake, is a Eurasian non-venomous snake. It is often found near water and feeds almost exclusively on amphibians. It is usually dark green, brown or gray in color with characteristic yellow spots behind the head. Reaches a length of 140 cm.
3. Smooth snake. The smooth snake is a species of non-venomous snake in the family Colubridae. The species is found in northern and central Europe, but also as far east as northern Iran. It reaches 65 cm in length, in very rare cases - up to 90 cm. It is gray in color, sometimes with a brownish tinge, but there are also forms with a copper-red color.
4. Eryx Jaculus. Eryx jaculus, known commonly as the javelin sand boa, is a species of snake in the Boidae family. Reaches a length of 50-75 cm. The back of the snake is yellowish-brown with irregular lighter spots that alternate with darker ones. One of the favorite places of the sand boa is the sand, where it is easily buried and moves under it. It also inhabits stony places, loose and sandy soils.
5. European Cat Snake. The European cat snake, also known as the Soosan snake, is a venomous colubrid snake endemic to the Mediterranean and Caucasus regions. It usually reaches 70-80 cm, maximum up to 110 cm in length. It is colored from light gray to whitish-yellow, with transverse dark spots on both sides of the dorsal line. The cat snake is found on the Adriatic coast of the Balkan Peninsula, in the valleys of the rivers Struma and Arda. There is a fig-weak poison for small prey.
6. Platyceps Najadum. Platyceps najadum, known commonly as Dahl's whip snake, the slender whip snake, and the Zagros whip snake, is a species of snake widespread in the western and southern parts of the Balkan Peninsula. Reaches a length of 1.5 m. It is not poisonous, and does not bite hard when threatened. It is very agile and moves extremely fast on the branches of bushes and trees.
7. Red Whip Snake. The red whip snake or collared dwarf racer is a species of snake found in the Eastern Mediterranean and the Southern Black Sea Coast. It reaches a length of 1 m and resembles a related arrow. Prefers rocky terrain with sparse shrubs. It is active during the day. Its main food is lizards.
8. Aesculapian Snake. The Aesculapian snake, is a species of nonvenomous snake native to southern parts of Europe and the Middle East, including Bulgaria. It reaches 1.8 m in length. It is not poisonous, but it bites hard when threatened. In ancient Greek mythology, it is one of the symbols of the healing god Asclepius. The Aesculapian Snake prefers old deciduous and mixed forests. It is active during the day, climbing trees and bushes well.
9. Xerotyphlops Vermicularis. European worm snake is a species of snake distributed in Southwest Asia and the Balkans. In appearance and underground way of life resembles an earthworm. Reaches a length of 35 - 40 cm. The worm snake prefers dry areas with grassy vegetation and rare shrubs. It spends most of its life underground, coming to the surface in warm and humid weather, most often at night.
10. Four-Lined Snake. The four-lined snake is a non-venomous species and one of the largest of the European snakes found through the west coast of the Balkan Peninsula and Macedonia, including Bulgaria in the Struma Valley to the Kresna Gorge to the north. Prefers wooded areas.
11. Malpolon Monspessulanus. Reaches 2 m in length. The color of the back varies from dark to light gray, and young individuals are colorful. It is a very agile snake, which in case of danger is quick to hide. Unable to escape, however, it is aggressive, hissing and biting furiously. It lives on sunny slopes, overgrown with bushes and low trees in southern Bulgaria.
12. European Ratsnake. The European ratsnake or leopard snake, is a species of nonvenomous colubrid snake endemic to Europe, Asia Minor, and the Caucasus, including the valley of the Struma River and here and there in the region of the Southern Black Sea Coast. The body of the leopard snake reaches a length of 110 cm. In the variegated form, the light brown back is dotted with large, oval-shaped reddish-brown or bright red spots, outlined with a black stripe.
13. Blotched Snake. The Blotched snake is a nonvenomous snake found in Eastern Europe, distributed in Thrace, Northern Bulgaria, the Danube parts of Romania, the southern parts of Moldova, Ukraine and Russia. It lives mainly in areas with steppe vegetation, and its main food is rodents.
14. Caspian Whipsnake. The Caspian whipsnake also known as the large whipsnake, is a common species of whipsnake found in the Balkans and parts of Eastern Europe, including Bulgaria. It reaches 2.5 m in length. It is not poisonous, but it bites hard when threatened. Avoids medium and high mountain areas.
15. Horned Viper. Vipera ammodytes is a viper species found in southern Europe, mainly the Balkans, and parts of the Middle East. It is considered one of the most dangerous European snakes because of its long teeth and relatively strong venom. The Horned Viper reaches a length of 50 - 70 cm, very rarely over 100 cm. The head is triangular in shape and covered with small unevenly spaced scales. At the top of the front shields there is a specific horn, which is very easy to recognize.
16. Common European Viper. Vipera berus is a venomous snake that is extremely widespread and can be found throughout most of Western Europe and as far as East Asia. It is one of the most cold-resistant reptiles in the world. The viper has a relatively thick body, with adults reaching an average length of 55 cm. The head is large and well defined, almost flat and vertical on the side, with a defined edge of the muzzle. On the Balkan Peninsula, the viper is found in isolated areas, mainly in the mountains up to 2700 m above sea level.
17. Vipera Ursinii. Vipera ursinii is a venomous viper and a very widespread species found in the steppes of Eurasia and in some isolated localities in Central and Southern Europe.
18. Vipera Aspis. The asp, also called a stonecutter, is a species of snake in the Poison family. Only two specimens were found in Bulgaria at the beginning of the 20th century. One is from the Harmanli area and was caught in 1933. The Aspis prefers sunny areas with relatively dry soils.