Harmless, although it looks like a venomous adder snake...
Anyway, the viperine grass snake is shorter and less common than the ringed grass snake, and leads a very secluded life in boggy areas beside streams and lakes, especially in Southern Europe. Grass snakes are good swimmers and divers and spend most of the day in the water, though they are difficult to spot because they sometimes spend long periods motionless at the bottom of the water without coming up for air. In the morning they like to lie in the sun among the tufts of grass at the water's edge. They are fairly gregarious as snakes go, and are occasionally found in groups and especially during their mating season in the spring.
Viperine grass snakes feed on cold-blooded animals, mostly frogs and small fish. They lie in wait for a fish, then hurtle forward and seize it in their jaws which are studded with sharp, backward-slopping teeth. They devour their prey just as well under water as on land. Like the majority of European grass snakes, they are harmless and totally lack venom fangs.
Image Credit: http://www.herpsafari.nl/reptiles/snakes/ [URL is no longer valid]
---End of Post "Viperine Grass Snake"