Document Type


Date of Degree Completion

Winter 2024

Degree Name

Master of Science (MS)


Primate Behavior

Committee Chair

Mary Lee Jensvold

Second Committee Member

Jessica Mayhew

Third Committee Member

Catherine Hobaiter


Culture can be defined as acquired behaviors that are repeatedly transmitted among individuals, rendering that behavior a community-level characteristic (Whiten et al., 1999). Chimpanzees (Pan troglodytes) have a wide repertoire of gestures within their communities (Hobaiter & Byrne, 2011) with most gestures being shared across both other chimpanzee communities, as well as other species of large-bodied apes (Byrne et al., 2017). Variation in grooming gestures between several wild chimpanzee communities across Africa suggests cultural variation (McGrew et al., 2001). Some communities use the grooming handclasp (GHC), while it is absent in others (McGrew & Tutin, 1978). More so, there is preliminary evidence that there are variations in the form of this gesture between communities (van Leeuwen et al., 2012). Some communities exhibit a palm-to-palm clasp, while others exhibit a wrist-to-wrist clasp (McGrew et al., 2001). This project examined gestures during interactions across wild communities. This study used video recordings of free-living eastern chimpanzees (P. t. schweinfurthii) residing at Gombe Stream National Park, Kibale National Park, and Budongo Forest. From these videos, gestures were identified. The form of two gestures, Big Loud Scratch (BLS) and Reach, was compared between three communities. In BLS there were significant differences between communities for use of place, direction, and audibility. In Reach there were significant differences between communities for use of movement, direction and palm hand orientation. Using methodology to describe the form of signs in American Sign Language, this study aimed to deepen our understanding of differences in gestural form.

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