在多數靈長類社群中，個體間存在著複雜而穩定的社會關係，Kawamura (1958)提出在重用親屬(nepotism)母系社會中的母系位階繼承(maternal dominance hierarchy，MRI)規則，指出其成年雌猴遵循 (1)母親位階的繼承，(2)母親的優勢，及(3)最年輕的優勢。台灣獼猴(Macaca cyclopis)生活於具有明確階級制度的母系社會中，推測母系中母女、姊妹、祖孫的親屬關係亦應是影響個體間位序的社會因子，以母親和高位階非直系親屬尤為重要。本研究以姊妹的母親存在與否以及與高位階非直系親屬的互動來探討影響姊妹間獲得位階和維持位序的決定因子。採用焦點動物取樣法，針對宜蘭福山試驗林A1猴群五對不同母系姊妹與母親和高位階非親屬成年雌猴的行為互動進行觀察。並以特定行為取樣法，記錄姊妹與母親和高位階非親屬之互相理毛及衝突發生時之介入和聯盟等社會行為互動。 有母親之姊妹的位序完全遵循MRI規則，而無母親之姊妹的位序則是繼承母親的位序，但妹妹的位階並沒有超越姊姊。妹妹與母親的友好互動較頻繁，包括有較高的理毛互動頻度與親近度，在紀錄到的姊妹衝突中，母親曾介入支持妹妹，高位階非親屬成年雌猴亦曾被觀察到與妹妹形成聯盟，僅在無母親的高位階母系姊妹間曾紀錄到聯盟的形成。姊妹對的位序與年紀排序與高位階非親屬成年雌猴的理毛互動頻度並無一致的關係，有母親的姊妹對中，高位階母系最年輕妹妹與高位階非親屬成年雌猴有較高的理毛互動頻度，但其餘二對姊妹的妹妹與高位階非親屬成年雌猴的理毛互動較少，然而所有妹妹們皆為理毛互動中的提供者。研究結果顯示，台灣獼猴姊妹位序受母親及高位階非親屬成年雌猴影響，而與母親或與高位階非親屬成年雌猴有較高的友好互動頻度與姊妹位階之獲得及位序之維持有關。
In most gregarious primate species, there is a complex and stable social relationship among groupmates in a social group. Kawamura (1985) reported that in nepotistic matrilineal societies adult females would follow the matrilineal rank inheritance rule (MRI), in terms of the acquisition of social dominance. The MRI rule suggests that females exhibit maternal rank inheritance, maternal dominance, and youngest ascendancy among sisters. Since Taiwanese macaques (Macaca cyclopis) live in matrilineal societies which display clear social dominance hierarchies, I hypothesized that kingship would affect the acquisition of a female’s social ranking. Besides, high-ranking non-kin adult females may also play an important role in social rank acquisition and maintenance in females. The aim of this study is to understand how mother and high-ranked non-kin adult females affect the acquisition and maintenance of social dominance in females, by examining their pattern of social interactions with the female. Focal animal sampling was conducted on five pairs of sisters in the A1 group at Fu-shan Experimental Forest, to collect data on their social interactions. I also conducted behavior sampling to collect information on allogrooming, agonistic interactions, and formation of alliance. Sisters with mothers living in the group followed the MRI rules completely, however, sisters without mothers only “inherited” their mothers’ rank, and younger sisters did not outrank older sisters. Younger sisters interacted socially with mothers more frequently. They allogroomed with mothers more frequently and stayed in proximity with mothers. Mothers intervened and supported younger sisters in the agonistic interactions involving sisters. The high-ranked non-kin females also formed ailliances with younger sisters. Among sister pairs, there was no consistent effect of social dominance and age of sisters on the frequencies of allogrooming with the high-ranked non-kin females. However, younger sisters were grooming provider in those allogrooming events. In conclusion, mothers and high-ranked non-kin adult females played an important role in the acquisition of social ranks in female Taiwanese macaques. Females maintained their social dominance through affiliative interactions, such as providing grooming, with mother and high-ranked non-kin females.