Abstract # 13107 Event # 131:

Scheduled for Friday, August 10, 2018 11:30 AM-11:45 AM: (Chula Vista ) Oral Presentation


J. A. Teichroeb1,2 and S. M. Stead1,2,3
1Dept. of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C1A4, Canada, 2Dept. of Anthropology, University of Toronto, 3School of the Environment, University of Toronto
     Across nonhuman primates, multi-level societies have been confirmed in several species of papionins and Asian colobines. Using eight months (848 hours) of demographic data on Rwenzori Angolan colobus (Colobus angolensis ruwenzorii) at Lake Nabugabo, Uganda, we documented the first multi-level society in an African colobine. Our study band (TR), is composed of 119 individuals in 12 cohesive core units (range: 5-19 individuals) that fission and fuse with one another throughout the day. Five core units are uni-male/multi-female and seven are multi-male/multi-female (mean: 3.71 males, range: 2-7), with no all-male units present, making this society unique among nonhuman primates. Here, we sought to determine the number of tiers of social organization in the Nabugabo population. We scanned the units within 50 m of the focal unit every two hours on 41 days (n=150 scans) and used hierarchical cluster analysis to determine if the association indices among units differed from random. We found preferential association of some units [Wilcoxon Z=2.07, p=0.039], indicating a clan level of organization within the band. In addition, 0.714 times/month TR band joined up with another band (MK) of approximately 60 colobus to form a large troop, traveling together usually for only a single day before breaking up. Thus, we found evidence of four tiers of social organization for Rwenzori Angolan colobus, the core unit, the clan, the band, and the troop.