Not a Thamnophis, but a related representative from the Natrix-species.
The snake escaped somewhere from its terrarium, we think.
It was placed in our Reptilezoo.
Nobody wanted it back and after a few weeks I have adopted it.
The people who found it (and the media also) thougt it was a venemous adder, Vipera berus, because it has a zigzag stripe on its back.
But this snake is a Viperine grass snake, Natrix maura and not venemous.
