The pant-hoot is not only one of the best-studied chimpanzee vocalizations but also the most conspicuous. This call is produced in a variety of contexts and often functions in communication between distant parties. Pant-hoots can be produced solitarily or in a chorus and are often heard during socially exciting events.
The pant-grunt is a rapid series of grunts separated by audible inhalations. It is typically given as a greeting and is always directed up the dominance heirarchy, meaning that higher-ranking chimpanzees never pant-grunt to lower-ranking chimpanzees. While the pant-grunt is often produced during relatively calm social contexts, it can grade into pant-barks and even pant-screams as the threat of aggression increases. Researchers often use data on the direction of pant-grunt production to determine and keep track of the dominance heirarchy.
Chimpanzees produce rough-grunts exclusively in feeding contexts. They may be produced in anticipation of food, upon discovery of food, or throughout the course of a feeding bout (Goodall, 1986). Because they are only produced when food is nearby, listeners who hear these calls may be able to learn about the presence and potentially properties of this food (Slocombe and Zuberbuhler, 2005). This particular recording was made when a party of chimpanzees arrived at a tree full of new fruit.
Screams typically occur in agonistic contexts and can be produced by both the victim and aggressor. They are also produced by juveniles during “tantrums”, particularly during the weaning process. Screams are thought to elicite aid in times of distress. One study even found evidence that victims may exaggerate their screams when invididuals that are higher ranking than their aggressor are nearby (Slocombe and Zuhberbuhler 2007).
Crockford, C. and Boesch, C. Context-specific calls in wild chimpanzees, Pan troglodytes verus: analysis of barks. Animal Behaviour, 66, 115-125.
Goodall, J. 1986. Chimpanzees of Gombe: patterns of behavior. Cambridge: Harvard University Press.
Hopkins, W.D., Taglialatela, J. and Leavens, D.A. 2007. Chimpanzees Differentially Produce Novel Vocalizations to Capture the Attention of a Human. Animal Behaviour, 73:2, 281-286.
Slocombe, K. and Zuberbuhler, K. 2005. Functionally Referential Communication in a Chimpanzee. Current Biology, 15, 1779-1784.
Slocombe, K.E. and Zuberbuhler, K. 2007. Chimpanzees modify recruitment screams as a function of audience composition. PNAS, 104:43, 17228-17233.