Page 191 - Demo

Proceptive vocalisations in orang-utan females1898Figure 3. Comparison between Temmy’s vocal response to other vocalisations known in the orang-utan repertoire. Analysed aspects of the vocalisations were: total call duration (s), Peak frequency (loudest frequency of the call), fundamental frequency (lowest frequency of the call), Inter-onset-interval (time between start of one vocalisation to start of next vocalisation within the call). B-f indicate 5 different orangutan calls that bear certain similarities to Temmy’s vocal response. Neither of them can be categorized as the same call that Temmy is producing.the whole duration. One call could continue for up to 60 seconds with steady IOIs, which bears more similarity to the long stable duration of the long-calls which generally last between 60 and 120 seconds. With respect to the fundamental and peak frequency, Eloise’s calls were closer to the male long call compared to Temmy’s (average Eloise fundamental frequency: 300 Hz, male long-call around 350 Hz, Figure 5). Tom Roth.indd 189 08-01-2024 10:42