Abstract # 228:

Scheduled for Monday, September 19, 2011 11:45 AM-12:00 PM: Session 30 (Meeting Room 410) Oral Presentation


J. M. Stevens1 and S. Wind2
1Centre for Research and Conservation, Royal Zoological Society of Antwerp, K. Astridplein 26, Antwerp B2018, Belgium, 2University of Utrecht, Department of Behavioural Biology

Regurgitation and reingestion (RR) has been described for a number of primate species in captivity, but received most attention in gorillas and chimpanzees. We studied a group of 9 bonobos in Planckendael Wild Animal Park, Belgium from April 2010-March 2011. We used an experimental design to investigate what the effect was of 1) increased browse; 2) reduced fruit and 3) combination of increased browse and reduced fruit. Three individuals showed manual stimulation of the throat before regurgitating the food. The fourth individual did not show any external manipulation. We present evidence that the manually stimulated RR is socially learned, which may have implications for reducing or eradicating the behaviour. RR was clearly linked to feeding time, showing a strong peak in the morning and a larger peak in the late afternoon. In general, the bonobos performed more RR after food that was rich in sugar contents (fruit, primate pellets, carrots). We found a significant effect of dietary condition on RR for the two males that showed this behaviour most frequently (Kruskal Wallis Anova chi = 13,16 p<0.05). Post hoc tests showed that RR diminished significantly only in the reduced fruits conditions. Increasing the amount of browse did not reduce frequencies of RR. Results support the “favourite food hypothesis”, indicating that sugarrich fruit may trigger the behaviour.