Described in detail by Miller (1912a) and Hinton (1926a); reviewed by Gromov and Polyakov (1977) and Corbet (1978c, 1984). Intraspecific chromosomal variation and extraordinary genetic system of sex determination leading to female-biased sex ratio documented by Gropp et al. (1976), Kozlovskij (1986), Fredga et al. (1976, 1977, 1993), and Gileva and Fedorov (1991). Departures from the usual 2n = 32 documented for Siberian samples (Gileva et al., 1983; Kozlovsky, 1985), but the chromosomal difference does not signify more than a single species (Jarrell and Fredga, 1993). Genetic variation is low in populations from Western Siberia and Scandinavia (Fedorov, 1990, 1993; Fredga et al., 1993). Using isozyme analysis, Fedorov et al. (1994) recorded significant genetic divergence between the Fennoscandian, Western Siberian, and Eastern Siberian regions but little differentiation among populations within each. Age and geographic variation among Norwegian populations assessed by Kratochvíl (1979).

Courant et al. (1997) discovered cranial shape convergence between M. schisticolor and certain voles and discussed possible ecological influences for such parallel shape changes in distantly related arvicolines. Regarded as rare, but Emelyanova (1994) found wood lemmings to be a dominant species in small mammal communities of the taiga zone, NE Siberia, forming the primary food of hawk owls.