Recognized as a species since Ellerman (1941); N. niviventer later came to embrace populations extending from Nepal through Indochina, Malay Peninsula, and some islands on the Sunda Shelf (Ellerman, 1961; Ellerman and Morrison-Scott, 1951; Niethammer and Martens, 1975); some of the names associated with N. niviventer in those reports now identify separate species or are synonyms of others (N. confucianus, N. culturatus, N. fulvescens, and N tenaster; see those accounts). "There is yet no convincing evidence that the Nepalese populations are the same as those from areas farther east in northern Burma and China" (Musser, 1981b:253), or from Thailand (Abe, 1983:160), or anywhere else in Indochina or on the Sunda Shelf. Multivariate analysis of morphometric traits incorporating samples of most named forms in Niviventer isolates N. niviventer from clusters containing the four species listed above (Musser and Lunde, ms).

Our study of specimens in museum collections indicates the geographic distribution of N. niviventer to be strictly Himalayan as outlined by Corbet and Hill (1992). Agrawal (2000) included Bhutan, NE India (Assam, Nagaland, Arunachal Pradesh, Meghalaya, and Manipur), and Burma within the range of N. niviventer, but material we have seen from Burma is either N. confucianus (in the north) or N. tenaster (WC and S Burma; see those accounts), and samples from NE India are N. fulvescens; we have not seen Agrawal’s material in ZSI. Agrawal noted that specimens from NE India are larger than those from Nepal and Sikkim, and we suspect they may represent N. confucianus, which is a larger animal (Musser and Lunde, ms), or even misidentified N. fulvescens. To finally resolve easternmost limits of N. niviventer and westernmost of N. confucianus will require reexamination of Agrawal’s series from NE India. Biology, habitats, morphological variation, and taxonomy reported by Abe (1971, 1977) for samples of N. niviventer from C Nepal. See account of N. confucianus.