Recognition of female fertilization and social rank by male golden snub-nosed monkeys (Rhinopithecus roxellana)
ZHAO Haitao, WANG Xiaowei, HOU Dafu, WANG Chengliang, REN Yi, FU Weiwei，LI Baoguo
1 Shaanxi Key Laboratory for Animal Conservation, Shaanxi Institute of Zoology, Xi’an 710032, China) (2 College of Life Sciences, Northwest University, Xi’an 710069, China) (3 District Administration of Shaanxi Micangshan National Nature Reserve, Xixiang 723500, China)
Abstract Social animals possess important cognitive abilities that help them adapt to complex and variable environments, as well as comprehend their position and that of others within their social groups. Identifying which cognitive behavioral strategies are adopted to maximize reproductive benefits and gain access to resources is an important area of study in primatology. To date, however, research on the recognition of social rank and pregnancy status in golden snub-nosed monkeys (Rhinopithecus roxellana) remains poor. Here we investigated the hierarchical relationships and pregnancy cycles of females from six one-male units (OMUs) located within a provisioned group of golden snub-nosed monkeys from the Guanyinshan Nature Reserve in the Qinling Mountains of China. We used instantaneous scan and focal animal sampling to collect data on spatial position and reproductive behavior to clarify the mating period and analyze differences before and after fertilization. We confirmed significant differences in the rates of sexual solicitation success (t = 4.527, P = 0.001) and found that the rate before fertilization was significantly higher than that after fertilization. Results also demonstrated significant positive correlations between rank status and the rate of solicitation success (R = 0.527, P = 0.006) and time of fertilization (R = 0.556, P = 0.049), which were found to be significantly higher and earlier, respectively, in higher-ranked females than in lower-ranked females. This study revealed that males were able to recognize the pregnancy status and rank of females within their OMUs, which affected their own social and reproductive behavior.