Summer marks peak viper season in Denmark, when the country’s only venomous snake, the common European adder, becomes especially active. While fatal bites are rare, experts advise caution and immediate medical attention if bitten.
Denmark’s Only Venomous Snake Active During Summer
Denmark is home to just one venomous snake: the common European adder (Vipera berus), known locally as the “hugorm.” With its signature zigzag pattern along its back and its preference for sunny, warm habitats like heathland and forest edges, the adder thrives during the Danish summer. Its active period, especially in July and August, coincides with people spending more time outdoors, increasing the risk of encounters.
Although not typically aggressive toward humans, adders can bite if they feel threatened or are accidentally stepped on. Most people go their entire lives in Denmark without encountering one, yet an estimated 200 to 400 people are bitten each year, according to healthcare officials.
Not Dangerous—but Not Harmless Either
Medical professionals emphasize that while an adder bite can be painful and lead to significant swelling, serious complications are rare. Deaths are extremely uncommon. In fact, the last confirmed fatality from an adder bite in Denmark occurred in the early 1980s. However, this does not mean bites should be taken lightly. In some cases, the venom can cause severe symptoms including low blood pressure, dizziness, and extensive bruising and swelling.
For about 30 percent of bites, no venom is injected. These “dry bites” result in minimal symptoms. But when venom is delivered, prompt medical attention is crucial to manage pain and swelling and to prevent any long-term effects.
What To Do If Bitten
If someone suffers a bite, it is important to stay calm and limit physical movement. Movement can accelerate the spread of venom through the bloodstream. Victims should avoid attempting any home remedies such as cutting near the bite, sucking out the venom, or applying a tourniquet. These methods can worsen the injury or introduce infection.
Instead, the bitten person should remain still and seek medical attention immediately. In more severe cases, doctors may administer antivenom, which neutralizes the effects of the venom and can prevent lasting damage, particularly when swelling and pain persist for weeks or even months.
Most Incidents Occur in Jutland
According to a review of 20 years of data, approximately 60 percent of reported adder bites occur in Jutland, the mainland portion of Denmark. The majority of those bitten are men between the ages of 20 and 50, and the legs and feet are the most commonly affected areas. This is likely due to people hiking or working outdoors wearing low footwear.
Though Gold-standard statistics report around 50 inquiries to the Danish Poison Line (Giftlinjen) annually regarding adder bites, only a fraction result in serious medical intervention. So far this year, just 14 calls have been made—but this count is expected to rise with the peak summer months.
Where Are Adders Found?
Adders prefer sunlit areas with dense ground cover. Common hiding spots include stone walls, forest edges, open heathlands, and occasionally urban gardens with thick hedgerows. In one notable incident, a man spotted an adder inside his garden hedge while trimming it—an unusual situation but not impossible. Typically, the snakes will retreat if they sense vibrations from people nearby, but they may strike when surprised or cornered.
Adders come in a variety of colors, including black. This can lead to confusion with other non-venomous snakes such as the grass snake. However, grass snakes can be identified by their two distinctive yellow neck markings, which adders lack.
Protected but Potentially Dangerous
The common adder has been a protected species in Denmark since 1981. Killing or harming them is illegal, even though some people may view them as dangerous. Instead, experts recommend taking precautions such as wearing boots when hiking and keeping dogs on leashes in areas known for snake activity.
For pet owners, particularly dog owners, it’s important to stay vigilant. Dogs are naturally curious and may disturb an adder, resulting in a defensive bite. In such cases, veterinary care should be sought immediately.
Though the risk of a deadly snakebite in Denmark is minuscule, awareness and preparedness can ensure a safe and enjoyable summer outdoors.
