Among the Gro TshangTibetans in northeastern Qinghai Province, the whole society is divided into three rus pa (or bones) strata according to whether and to what extent a specific clan gives off armpit odor.

• 生活在青海东北部的卓仓藏人 ,根据每个家族有无狐臭体味遗传及其程度 ,把整个社会划分成三个骨系阶层 ,每个阶层就是一个内婚群体。