the calls. To counteract these effects, individuals living within a forest habitat will produce slower, low frequency calls, which slow the rate of attenuation and reduce the risk of degradation of the pant-hoot, in comparison to individuals living in open areas and fields, where the need for this structural modification is reduced. Finally, the variable structure of chimpanzee pant-hoots amongst populations may be attributable to experience, based on the theory of vocal learning. Chimpanzees possess specific individual characteristics of their pant-hoots as a mechanism for recognition by other members of their social groups. However, when engaging in chorusing behaviours with other males, each participant displays call convergence, in which the calls of each individual resemble the other, in the formation of a group-specific call. The learning of these group-specific calls provides a method for rapid identification of members within the same affiliative group, allowing for an increased benefit when engaging in intraspecies conflicts, allowing members to distinguish their allies from their opponents. The production of group-specific calls demonstrate the variability in the structure of chimpanzee pant-hoots as these behaviours and specific calls are a learned mechanism to distinguish neighbouring populations from one another, as each population maintains modifications to their pant-hoots in relation to the next, illustrating the structural diversity of the pant-hoot with respect to vocal learning. Production Chimpanzees tend to alter the production and duration of pant-hoots based upon their dominance rank with respect to other individuals and the locational risk and human influences associated with the production of these loud, long-distance vocalizations. High-ranking, dominant males produce longer and more frequent pant-hoots than individuals of a lower social status. This may be attributed to sexual selection for high levels of call production, as this indicates the high quality and dominance of the calling individual to conspecifics and prospective mates. The production of pant-hoots are related to the formation of social status as calling facilitates the formation of strong social bonds and affiliations between members, equivalently increasing the displayed coalition, strength and essentially dominance of each individual in the socially affiliated group. Increasing the display of strength and dominance increases the attraction of mates, and ultimately fitness, resulting in the selection of these dominant males with increased production of pant-hoots rather than lower-ranking males. Chimps will also alter the production of calls based on the situational circumstances of their location. In areas where chimps are at a high risk