Sign acquisition in a home-reared/free-ranging orangutan: Comparisons with other signing apes


  • Gary L. Shapiro

    Corresponding author
    1. University of Oklahoma and Orangutan Research and Conservation Project
    • Department of Zoology, University of Oklahoma, Norman, OK 73019
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A young female orangutan that was maintained in a home-reared/free-ranging environment acquired 37 signs (Ameslan) after 19 months of training. Analysis and qualitative comparison of the initially produced signs revealed that an orangutan developed a vocabulary of signs in a manner similar to that of a chimpanzee and gorilla. This substantiates the general pongid ability to acquire manual signs.