1Thompson Writing Program, Duke University, 2Section in Human & Evolutionary Biology, Department of Biological Sciences, University of Southern California
March 27, 2015 , Archview Ballroom
Bonobos (Pan paniscus) and chimpanzees (Pan troglodytes) display diverse social dynamics, but it is unclear how their varying social structures and relationships influence gestural communication. This study examines patterns of signaling within dyads to determine how social dynamics shape gestural signaling in Pan. A total of 336 hours of ad libitum video of social interactions were collected from bonobos at the San Diego Zoo (SDZ) and San Diego Zoo Safari Park (SDZSP), and from chimpanzees at the Saint Louis Zoo (STLZ) and Los Angeles Zoo (LAZ). From the video footage, we coded gestures, social contexts during gesture use, and the recipient’s identity and response. All groups used between 27 and 33 distinct gestures, but there was inter-group variation in the rate of gestural signaling (SDZ=15.6 gestures/hour, SDZSP 36.1 gestures/hour; STLZ=14.5 gestures/hour, LAZ=6.8 gestures/hour). Among bonobos, adult females gestured almost equally to females and males of all ages, demonstrating their more egalitarian, female-dominant social structure. Among chimpanzees, adult females at STLZ gestured significantly more to other adult females (92.0%), while adult females at LAZ gestured significantly more to juvenile males (62.8%). This inter-group variation is likely due to differences in group composition and affiliation among females. Adult males of both species gestured significantly more to group females than any other age/sex class. Results suggest that aspects of each species’ distinctive social dynamics are reflected in their patterns of gestural signaling. However, findings also indicate that gestural communication is flexible and highly dependent on group composition and group-level social dynamics.
Funding for this research was provided by the CUNY Mario Capelloni Dissertation Award, American Association of University Women American Fellowship, NYCEP (NSF DGE 0333415), and Sigma Xi Grant-in-Aid of Research.