The development of the pant-hoot call in wild male chimpanzees

The pant-hoot is the chimpanzee long distance call. It is used in different context such as feeding and travelling to give other community members information about the location of an individual or a party. It is one of the most important calls for chimpanzees as it allows a certain cohesion within a community that is often scattered in a deep forest. This call is usually composed of four phases: introduction, build up, climax and let down.

During my master project I am interested in the development of such a call in young chimpanzees. How do they learn how to pant-hoot?

It has already been observed that the pant-hoot is more similar within a community than between different communities. Moreover, it is also known that the pant-hoot can vary between individuals from the same community. Why would some chimpanzees have more similar pant-hoots than others?

Between 10-15 years old, sub-adult males become independent from their mother. Around this age, they learn how to pant-hoot and already often spend their time with adult males.

I am wondering if these sub-adults have a more similar call to their affiliated males than other males. This would give credit to an active learning of this complex call.

To look at this hypothesis I studied the Waibira community of the Budongo forest in Uganda during 5 months (2015-2016). I followed around 20 males of different ages recording their pant-hoots and taking social data such as party composition.

As I am now analysing these data I am suggesting that the inter-age class between sub-adult and adult (15-20 years old) could be very important for the development of the pant-hoot call