Mustela nivalis Linnaeus, 1766 —Least Weasel

Mustela nivalis Linnaeus, 1766 p.69; Type locality- Sweden; Ellerman & Morrison-Scott, 1951 p.256; Won, 1968 p.282; Han, 1994 p.46; Won & Smith, 1999; p.19; Oh, 2004a p.169.

M. nivalis mosanensis Mori, 1927 p.28; Type locality- Yeonam (near Musan), Korea; Kuroda, 1938 p.29; Ellerman & Morrison-Scott, 1951 p.258; Won, 1958 p.438; Won, 1967 p.113; Won, 1968 p.283.

M. pygmaea mosanensis: Kishida & Mori, 1931 p.380 .

M. nivalis nivalis: Corbet, 1978 p.169; Yoon, 1992 p.102.

Range: Previously, mammalogists thought the least weasel in Korea had a distribution limited to the northeastern Korean Peninsula (Won 1968). However, although very rare, the least weasel is now found throughout most of the Korean Peninsula (NIBR 2012; Fig. 47).

Remarks: The least weasel is recognized in Korea as the Subspecies M. n. mosanensis (Won 1968). Corbet (1978) relegated most populations in Eurasia, including M. n. mosanensis, to a synonym of M. n. nivalis Linnaeus, 1766 . Abramov and Baryshnikov (2000) identified 19 subspecies and confirmed one subspecies, M. n. mosanensis, in the Korean Peninsula, despite difference in coloration between northern and southern Korea. Specimens from northern Korea showed nivalis -coloration in which the winter coat turns completely white; however, southern population showed vulgaris -coloration with incomplete white coloration in winter coats (Choi & Choi 2007).

Conservation status: The North Korean government designated habitat of M. nivalis in the Mayang District, Musan County, Hamgyeongbuk Province as a Natural Monument in 1980. M. nivalis in South Korea are regarded as ‘Vulnerable’ (NIBR 2012) and in North Korea as ‘Rare’ (MAB National Committee of DPR Korea 2002).