Weasels in Switzerland

The term „weasel“ includes two very similar animal species - the stoat (Mustela erminea) and the least weasel (Mustela nivalis). Together with the European polecat (Mustela putorius), the next relative of the two weasel species, they form the genus „Mustela“.

The least weasel is the smallest predator in the world (and potentially the cutest). It is clearly smaller than the stoat and possesses a short tail with a brown tail-top. The stoat, on the other hand, has a black tail tip and turns white in winter.

How do Weasels Live?

Both species feed mainly on voles, other mice, birds, amphibians and invertebrates. Due to their typical body shape - elongated body and short legs - they are optimally adapted to mouse hunting and follow their prey even into the narrowest passages. They live solitary and defend their territory against competitors.

Due to the constantly fluctuating supply of prey, the density of weasel populations also fluctuates enormously.

Because of their preference for voles (a pest of many crops), weasels are welcome inhabitants of agricultural areas. However, weasels not only need a solid food source, but also hiding places, such as piles of branches, where they can hide from danger or where they raise their young. Additionally, they also need connecting structures that they can follow and seek protection in against predators during their dispersal. Hedges, for example, can provide such structures, since weasels can orient themselves from them and hide in them in the event of danger. Without these types of structures, even a field filled with voles will not be able to sustain a weasel population for long.

How are Weasels Doing in Switzerland?

This question cannot be answered easily. Unfortunately, very little is known about the weasel populations in Switzerland. It is well known that the increasing fragmentation of habitats is affecting them, but the state of the food supply of these elusive animals is still unclear.

With the weasel and the polecat, two of the three species in the genus Mustela are listed as vulnerable on the Red List of Endangered Species in Switzerland. This means that there is a high risk of these species going extinct in nature in the immediate future.

For many years, the WIN Wieselnetz Foundation has supported weasels in Switzerland and coordinates and supports many local projects.