Snakes are present in Scandinavia, though their numbers are relatively small. While encountering them is possible in certain natural environments, these reptiles are shy and prefer to avoid human interaction. They retreat when approached, making close encounters uncommon.
Native Snake Species
Scandinavia is home to three native snake species. The common adder, Vipera berus, is the only venomous snake found in the region. Adults measure around 55 centimeters, but some individuals can exceed 90 centimeters in length. Males are grey with a distinct black zigzag pattern along their backs, while females are brownish or yellowish with darker markings.
The grass snake, Natrix natrix, is a non-venomous species and larger than the adder, reaching lengths of up to 120 centimeters. This snake has an olive-green or brown coloration and is identifiable by a distinctive yellow or whitish collar behind its head.
The smooth snake, Coronella austriaca, is also non-venomous and is more slender, growing to 60-75 centimeters long. Its appearance is greyish-brown, featuring two rows of indistinct dark spots along its back and a dark stripe extending through its eye. The scales of the smooth snake are smooth to the touch, giving it its common name.
Identifying Snakes and Safety Measures
Distinguishing between the native snake species is important for safety. The common adder can be identified by its zigzag pattern down its back and its vertical, slit-like pupils. Its head is also triangular in shape.
In contrast, the non-venomous grass snake displays a prominent yellow or whitish collar behind its head and has round pupils. The smooth snake lacks a zigzag pattern and has smooth scales, showing a dark stripe that runs through its eye.
If you encounter a snake, remain calm and maintain a safe distance. Snakes are not aggressive and will only bite if they feel threatened, are stepped on, or are handled. Should a bite occur, keep the bitten body part as still as possible and seek immediate medical attention. While adder bites can be painful and cause swelling, fatalities are rare. Wearing appropriate footwear when walking in areas known to have snakes can help prevent accidental encounters.
Distribution and Preferred Habitats
The common adder, Vipera berus, is widely distributed across Scandinavia and much of Europe, extending north of the Arctic Circle. These adders inhabit diverse environments, including mossy ground, forest edges, and open fields, basking in sunny spots. They avoid dense forests, preferring areas with ample sunlight.
The grass snake, Natrix natrix, is widely distributed across Scandinavia and mainland Europe, and is a strong swimmer. It resides near water bodies such as marshes, ponds, rivers, and ditches, as amphibians are a primary food source. While associated with wetlands, grass snakes can also be found in drier locations like gardens and open woodlands.
The smooth snake, Coronella austriaca, is present in southern Sweden and parts of Norway, largely absent from Denmark. In Finland, it is primarily restricted to the Åland archipelago. This species prefers dry, sunny habitats such as open woodlands, heathlands, rocky areas, and shrublands. Smooth snakes seek environments that offer open areas for basking alongside cover for shelter and hunting.