Atlas der Säugetiere Nordrhein-Westfalens

Mauswiesel

821 entries

Least Weasel

Rote Liste NRW: D Daten unzureichend

  entry

Mustela nivalis

The Least Weasel is by far the world ′s smallest carnivore. This slender mustelid is distinguished from the closely related Ermine not just by its small body size but also by its short tail, which lacks the black terminal section. Aside from that Least Weasels retain the brown colour as in summer, while Stoats usually have a white pelage in winter. Furthermore male Least Weasels are considerably larger than the females. For this reason, in particular small female individuals with a minimal weight of only 30 g formerly used to be viewed as Pygmy Weasels. Least Weasels can survive wherever mice and especially voles occur and if there is enough cover. Given their small size they pursue and prey on mice often directly in their burrows. Even when Least Weasels are active during the day one will see them only in exceptional cases.
A considerable part of older records relies on trap captures of hunters in small game hunting grounds. However, nowadays the species can no longer be hunted in NRW. The corresponding hunting bags, which unfortunately don′t list the two weasel species separately, show that the abundance of weasels clearly correlates with the fluctuation of vole densities from year to year. Given the changes in the agricultural areas in Germany during the past decades, which have also considerably impaired the living conditions of voles, it is to be feared that the populations of Least Weasels in NRW also clearly suffer from this. Least Weasels themselves frequently become victims of predators, even from cats. Even in pellets of barn owls one occasionally finds remains of this species.
The Least Weasel occurs throughout NRW. Thus free grid cells in the distribution maps usually mean that no attention was paid to the species.

Author

Henning Vierhaus

Citation

Vierhaus H (2025): Mauswiesel (Mustela_nivalis).In: AG Säugetierkunde NRW — Online-Atlas of the mammals of North Rhine-Westphalia. Downloaded from saeugeratlas-nrw.lwl.org on 2025/04/01