The diversity of Vipera berus

By Lennart Aiscan & Niklas Banowski

Black Forest - from dry meadows to montan moors

Vipera berus Kreuzotter adder Schwarzwald Black Forest Germany Deutschland
Vipera berus male Schwarzwald

In the Black Forest, Vipera berus is mainly distributed along the high altitude ridges in the centre and the temperate valleys in the east (Fritz et al. 2004). Along the ridges, their primary habitats mainly consist of bogs, light forests and open areas with distinct fern-, blueberry- and pine growth (Laufer et al. 2007). The more anthropogenic habitats in the valleys are mainly located in humid dens, where this species has taken on rock walls and field edges as a secondary habitat (Laufer et al. 2007). Other common anthropogenic habitats are railways and edges of forest roads, that have been established for the extensive logging in the area.
In most of the populations, melanism is very common, with rates of 50-99% melanistic individuals.

Pre Alps - flooded forests and moore moor

Vipera berus adder Kreuzotter Bayern Bavaria Germany Deutschland Chiemgau Italian clade marasso
Vipera berus male Bayern

Besides the big populations in the northern lowlands, the Black forest, and eastern areas of Germany the pre-alps inhabit an important number of the German adder populations (Schiemenz et al., 1996). Formed through glacials in the ice ages the pre-alps offer great conditions for adders. Besides the great alp rivers, Lech and Isar countless moors and flooded forests are the main habitats (Völkl et al., 2002, Heckes et al., 1993, Lehnert & Fritz, 1993). These  show diversity in their structure and their microclimate. As differentiated as the structure of the habitat are the colorations inside the populations. While one can be almost 80% melanistic, the other shows a bright variety of colors and patterns and if you are lucky might be completely reddish (Hansbauer & Völkl 2019). Also, the genetic diversity is special in these regions because in the pre-alps you can find two genetic clades of Vipera berus, the northern clade and the so-called Italian clade, which is considered as a subspecies "Vipera berus marasso" by some authors (Ursenbacher et al. 2006, Schmidtler, J.F. & G. Hansbauer, 2020). Concluded the pre-alps are an interesting area for adder fans and the transition zone to the next habitat type.

Alps - stone piles and mountain pastures

Vipera berus alps Switzerland Alpen Schweiz Adder Kreuzotter northern clade
Vipera berus alps Switzerland

Vipera berus is almost famous for its prevalence in the alpine regions upside the tree line. Their preferred habitat here is the knee-timber zone, which they share with black grouses and Co. The vegetation communities are build out of alpine pines (Pinus mugo), rough pasture to dwarf shrub heathland. In this altitude rough conditions dominate the year, late snowstorm and low temperatures are their daily business and so the adders need well-structured habitat to survive in this condition (Hansbauer & Völkl 1019). Vipera berus is a master in that and so you can find them up to an altitude of 2958m (Caldonazzi, 2006). Sometimes they need to wander a lot during the year to different habitat structures to achieve their optimal live conditions during the year, and during cold years the time of activity in a year can be limited to 100 days, a good example of how tough those animals are (Poulsen, 1962).

Northern lowland - humid forests and heaths

vipera berus adder lüsekamp kreuzotter germany NRW Nordrhein-Westfalen
Vipera berus Nordrhein-Westfalen Germany

 The main habitat structures in the northern lowland are mixed heath- moor - forest complexes, in areas where a good diverse structure of humidity, light, and vegetation can be found (Geiger A., M. T. 2009). A good indication of the right condition can be the grass species Molinia caerulae, which is often used as a home base of the adders (Müller, W.,1980). Problematically the high anthropogenic influence destroyed many good habitats and resulted in a high fragmentation of populations, which are decreasing or even went extinct. Just good structured moors with a continuous humidity level still have good populations and especially the Netherlands and northwestern heathlands are still a home for big populations (Geiger A., M. T. 2009,Schiemenz 1996).

50 shades of melanism

Vipera berus adder kreuzotter bayern bavaria isar
Vipera berus female Bayern

Melanism is very common in Vipera berus, reaching up to almost 100% rates in certain populations (Bohle & Thiesmeier 2017). The advantages of melanism lay in thermoregularization (Gibson & Falls 1979). Melanistic individuals reach significantly higher temperatures in significantly less time, than their regular colored conspecifics (Forsman 1995). These advantages favor melanistic adder males in sexual selection, as their larger size (at the same age as cryptic colored individuals) results in higher success rates in male to male combat (Madsen and Stille 1988). Female adders also profit from black coloration, as their offspring is on average more healthy, more numerous and born sooner than their cryptic colored conspecifics (Luiselli 1993). However, several studies have proven melanistic adders to be more vulnerable to predation, as they lack any crypitc, aposematic pattern (Wüster et al. 2004, Valkonen et al. 2011). The two trade offs vary in importance along different habitats, which in the end determine the rates of melanism in a population. Nearly all melanistic individuals are born with regular coloration. At a certain age (that can vary between sexes, populations and even individuals) the recoloration process begins, which sometimes results in distinct temporary colorations (Otte et al. 2020).

Anthropogenic & Behaviour

This little chapter is in the making and will show the very pronounced behavior of Vipera berus and how they come in contact with humans. Soon more!

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Forsman, A. (1995): Heating rates and body temperature variation in melanistic and zigzag Vipera berus: Does colour make a difference? Annales zoologici fennici 32:365–374.
Fritz, K.; Sowig, P.; Laufer, H. (2004): Verbreitung und Bestandssituation der Kreuzotter Vipera berus (Linnaeus, 1758) in Baden-Württemberg Mertensiella 15:108 - 116.
Gibson, R. A.; Falls, B. J. (1979): Thermal biology of the common garter snake Thamnophis sirtalis (L.) : II. The effects of melanism. Oecologia 43:99–109. DOI: 10.1007/BF00346675 .
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Valkonen, J.; Niskanen; B, Mats; Mappes, J. (2011): Disruption or aposematism? Significance of dorsal zigzag pattern of European vipers. Evolutionary Ecology 25:1047–1063. DOI: 10.1007/s10682-011-9463-0 .
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Geiger A., M. T. (2009). Kreuzotter - Vipera berus. In A. A. Nordrhein-Westfalen, Handbuch der Amphibien und Reptilien Nordrhein-Westfalens (S. 1107-1122). Bielefeld: Laurenti.

Müller, W. (1980): Zur Verbreitung, Ökologie und Biologie der Reptilien am rechten unteren Niederrhein - Niederrheinisches Jahrbuch 14: (S.91-97).

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Hansbauer und Völkl (2019): Amphibien und Reptilien in Bayern. Eberhard Andrä (Hrsg.), Otto Aßmann, Thomas Dürst, Günter Hansbauer, Andreas Zahn. 2019.

Poulsen C.M. (1962): Lidt om hugormen (Vipera berus L.) i vinertid. Flora och fauna 3:161-163)

Caldonazzi, M. (2006): Marasso, adder Atlas of Italian Amphibians and Reptilies: 600-605. - Firenze

Völkl (2002): Die Kreuzotter: Ein Leben in geregelten Bahnen?


Heckes, U., Gruber, H.J-, Haft, J. (1993): Verbreitung Habitatbindnug und Gefährdung der Kreuzotter Vipera berus (Linnaeus, 1758) in Südbayern. - Mertensiella 3: 331-341

Lehnert, M & Fritz, K (1993): Verbreitung und Klimaanspruch der Kreuzotter (Vipera berus berus L.) in Südwestdeutschland.- Mertensiella 3:343-356

Schmidtler, J.F. & G. Hansbauer (2020): Die Alpenkreuzotter (Vipera berus marasso), eine neue Unterart in den Bayerischen Alpen.- Zeitschrift für Feldherpetologie 27: 136-148