Social network and dominance hierarchy analyses at Chimpanzee Sanctuary Northwest

Different aspects of sociality bear considerable weight on the individual- and group-level welfare of captive nonhuman primates. Social Network Analysis (SNA) is a useful tool for gaining a holistic understanding of the dynamic social relationships of captive primate groups. Gaining a greater understanding of captive chimpanzees through investigations of centrality, preferred and avoided relationships, dominance hierarchy, and social network diagrams can be useful in advising current management practices in sanctuaries and other captive settings. In this study, we investigated the dyadic social relationships, group-level social networks, and dominance hierarchy of seven chimpanzees (Pan troglodytes) at Chimpanzee Sanctuary Northwest. We used focal-animal and instantaneous scan sampling to collect 106.75 total hours of associative, affiliative, and agonistic data from June to September 2016. We analyzed our data using SOCPROG to derive dominance hierarchies and network statistics, and we diagrammed the group\u27s social networks in NetDraw. Three individuals were most central in the grooming network, while two others had little connection. Through agonistic networks, we found that group members reciprocally exhibited agonism, and the group\u27s dominance hierarchy was statistically non-linear. One chimpanzee emerged as the most dominant through agonism but was least connected to other group members across affiliative networks. Our results indicate that the conventional methods used to calculate individuals\u27 dominance rank may be inadequate to wholly depict a group\u27s social relationships in captive sanctuary populations. Our results have an applied component that can aid sanctuary staff in a variety of ways to best ensure the improvement of group welfare

Experimental Conversations: Sign Language Studies with Chimpanzees

Sign language studies of chimpanzees are a tool for studying the continuity between human behavior and behavior of other animals and between verbal behavior and other intelligent behavior. Cross-fostered chimpanzees paralleled children in their acquisition and use of signs and phrases. These procedures occurred under rigorous and systematic record keeping and experimental paradigms. The study of Wh-questions and the use of remote videotaping (RVT) are examples of experimental procedures. These revealed chimpanzee-to-chimpanzee signing and private signing. Face-to-face interactions between the chimpanzees and an interlocutor who presented various systematic probes is another experimental procedure. The chimpanzees adjusted to the interlocutor with revisions, new signs, or no response when appropriate. The hallmark of the sign language studies is that caregivers treated the chimpanzees as conversational partners socially motivated rather than experimental subjects bribed or forced into participation. These findings confirm continuity with differences of degree among species