Adders are a type of snake belonging to the Viperidae family, commonly found in Europe and parts of Asia. They are known for their distinctive zigzag pattern along their backs, which helps them blend into their surroundings. Adders are typically small to medium-sized snakes, with adults averaging around 60 to 90 centimeters in length. These snakes are primarily terrestrial and prefer habitats like heathlands, woodlands, and grasslands. Adders are also known for being the only venomous snake in the United Kingdom. Their venom is used to subdue prey, mainly small mammals and amphibians, but they are generally not aggressive towards humans.