| Part one.Social organization and structure of a provisioning in Sichuan snub-nosed monkeysOn the basis of provisioning and identifying a group of Sichuan snub-nosed monkey (Rhinopithecus roxellana) in the north slope of the Qinling Mountains in Zhouzhi National Nature Reserve in Shaanxi, China (108° 16' 18" E , 33° 48' 68" N), we were able to observe the group between 0.5 and 50m away. In the 422 recording hours, Data recorded with verbal descriptions and sketches show the group was consisted of 8 one male units (OMU) from October 2001 to February 2002, total 63 individuals: 8 adult males, 26 adult females, 8 sub-adult females, 13 juveniles, and 8 infants. OMU size ranges from 7 to 12 individuals, the average number per unit was 7.9. Adult males : adult females : sub-adult females : juveniles : infants was 1: 3.3 : 1 : 1.6 : 1. Due to immature individuals joining, OMU's composition increased from winter to next spring. Ad libitum sampling was used to record the aggressive behavior and submissive behavior, Dominance index analyzing the data shows dominant ranking order among units: HT>HD > CM > TT > JZT > DZ > ZZ> BZT. Dominant unit tends to aggress subordinate unit, lower ranking unit was easier to be aggressed (r =0.90), easier to perform submissive behavior (r= 0.87).Part tow. Does allogroomiog serve a hygienic function in the sichuan snub-nosed monkeyTo test the hygienic functional hypothesis of allogrooming in the Sichuan snub-nosed monkey, we analyzed the distribution of such behavior over the body surface of individuals in the West Ridge Troop in the Yuhuangmiao region of Qinling Mountains, Shaanxi Province, China. Based on 113 days of observations of the troop, 293 allogrooming bouts were obtained by focal-animal sampling. We divided the body surface of the monkeys into 17 areas. Before data analyses, 12 subjects (specimen) were measured in order to calculate the size of each area. Each area was then ranked according to the level of accessibility to the recipient of the grooming bout: easy to reach, difficult to reach, and inaccessible. We performed three successive analyses to determine: 1) the overall distribution of allogrooming behavior on the body surface areas; 2) the overall distribution of allogroomed areas based on the three categories of accessibility; and 3) age and sex class differences in the allogrooming frequencies based on both the defined body surface areas and the accessibility categories. Our preliminary results showed that the allogrooming behavior concentrated primarily on the dorsal and anogenital regions. Accordingly, the postures of the dyads precluded them from facing each other, a potential social strategy adopted by these monkeys to reduce tension and decrease conflict. Allogrooming also occurred most frequently on body surface areas allotted to the inaccessible category. We found that the frequency of allogrooming for the difficult to reach areas was proportional to the size of the areas covered on the monkey's body. Furthermore, those areas that were easy to reach were less frequently allogroomed than expected. Finally, the findings on age and sex class differences showed that allogrooming were influenced by social ranking. The distributions of allogrooming behavior on the body surface areas strongly suggest that cleaning was an important motivation for the monkeys to engage in such activity; therefore, the results support the hygienic functional hypothesis. |
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