Gloger's Rule in long-tailed weasels (Mustela frenata)

"Coloration of head and foreparts in ten subspecies of long-tailed weasel, Mustela frenata.... In regions of heavy rainfall ... there is an increase in pigmentation and extent of blackish color backward over the neck and a decrease in extent of the white facial markings. In regions progressively more arid ... there is a decrease in pigmentation and extent of blackish color and an increase in extent of the white facial markings.... Beginning with the southernmost subspcies (fig. 1) and continuing northward to the northern subspecies (fig. 10) there is a darkening, next a lightening, and finally a darkening closely confomring to amounts of precipitation in the geographic regions concerned." (Hall 1951)