Melanistic Adder seen in the Transylvanian Carpathians

Paul White • Eastern Carpathians, Transylvania, Romania

In the forests of the eastern Carpathians in Transylvania, Romania, I encountered one of the most striking reptiles I have observed in recent years. Resting coiled among the leaf litter and grass was a uniformly jet-black viper. Its appearance immediately raised the question of whether this was a melanistic Common Adder (Vipera berus) or a Nikolsky’s Viper (Vipera nikolskii).

Melanistic Common Adder Vipera berus in Transylvanian Carpathians

Melanistic Common Adder observed in the eastern Carpathians, Transylvania, Romania.

The specimen was approximately 60 cm in length. Its entire body, including the head, exhibited a deep, uniform black coloration with the typical keeled scales characteristic of vipers. The robust build and dark eyes contrasted sharply with the surrounding vegetation.

Identification Process

Nikolsky’s Viper (Vipera nikolskii) is recognised as a distinct species (or sometimes subspecies) occurring mainly in parts of Eastern Europe, including eastern Romania, Ukraine, and adjacent regions. Individuals are frequently uniformly dark and can closely resemble melanistic Common Adders.

After careful consideration and community consultation, the consensus reached was that this individual is a melanistic Common Adder (Vipera berus). The decision was based on several key factors:

  • Geographic Location: Although Nikolsky’s Viper occurs in eastern Romania, its distribution is more restricted to the easternmost parts of the country. This observation was made in the eastern Carpathian forests of Transylvania, an area where melanistic Vipera berus are well documented and far more typical.
  • Local Expertise and Community Feedback: Experienced local naturalists and observers familiar with the regional herpetofauna, including a veterinarian working in the area, identified the snake as a melanistic Vipera berus. One comment noted: “As I know, vipera nikolskii can be found only in eastern part of Romania; I think it is a melanistic vipera berus.”
  • Morphological and Ecological Context: Melanism is a relatively common phenomenon in Common Adders, particularly in cooler, upland, or forested habitats where darker coloration may confer thermoregulatory advantages. The overall morphology, proportions, and habitat context aligned strongly with the highly variable V. berus.

This observation demonstrates the value of citizen science platforms such as iNaturalist and community discussions on X. Collective knowledge of local distributions and variation greatly assists in reaching reliable identifications.

Responsible Observation

While the encounter was thrilling, it served as a clear reminder of the need for caution in viper habitat. These snakes are generally shy and non-aggressive, yet their venom requires appropriate respect. I maintained a safe working distance while photographing the individual and subsequently exercised greater care when continuing along the trail.

Such sightings underscore the rich biodiversity of the Romanian Carpathians — a region where traditional land use and extensive forests continue to support significant wildlife populations.

This observation has also been documented on iNaturalist for the scientific record.

Explore responsibly and stay safe in the field.