Movement in our chimp group (part 4)

After the successful introduction between Lily, Sanaga and Homer, the chimpanzee EEP has given us its green light for transferring and adding a new female of Pan troglodytes troglodytes subspecies to our group. The EEP chose Bamia, a 12 years-old female born at Plzen Zoo in Czech Republic.
 
Transferred mid-May to La Palmyre, Bamia first spent several days getting used to her new keepers and the daily routine of the great apes exhibit. About one week after she arrived, we started with the protected contact (through a mesh barrier) so that she can get safely  acquainted to Lily, Sanaga and Homer. This first step went perfectly well, as shown in the video below.
 
During the presentation, no vocalizations are made by Lily, Sanaga and Homer unlike Bamia who makes "pant-grunts". These calls are part of affiliative behaviour, meaning that they are transmitting to the receiver a positive intention. To the opposite, agonistic behaviours are associated with aggression. In that precise context, the vocalizations made by Bamia are a sign of recognition of the existing hierarchy.