Vipera berus, commonly known as the common European adder or the common viper, is a venomous snake species found in different regions of Europe. This snake is characterised by its distinctively patterned skin that consists of a zigzag line running down its back. Many people use synonyms for Vipera berus to refer to this snake species including the European viper, common adder, common European viper or northern viper. Vipera berus is an important species of snake that plays a pivotal role in maintaining the balance of the food chain in its natural habitat, however, it is also responsible for many snake bites in Europe each year.