%0 Journal Article
%A Liebal, Katja
%A Rossano, Federico
%+ External Organizations
Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society
%T The give and take of food sharing in Sumatran orang-utans, Pongo abelii, and chimpanzees, Pan troglodytes : 
%G eng
%U https://hdl.handle.net/11858/00-001M-0000-002E-738D-7
%R 10.1016/j.anbehav.2017.09.006
%7 2017-10-09
%D 2017
%* Review method: peer-reviewed
%X Proximate factors of primate food sharing, in contrast to its evolutionary explanations, have received little attention. Active food sharing is considered prosocial, since possessors may benefit others by spontaneously passing food or by reacting to ‘signals of need’. However, in contrast to passive sharing, active food sharing is rare in most nonhuman primates. Surprisingly, previous research showed that captive Sumatran orang-utans actively share food more frequently than chimpanzees and bonobos, and hence, appear more prosocial. Yet these comparisons with the two Pan species were relying on previously published studies, which differed with regard to methods and food types used. Here we used the identical procedure and food type to compare the food-sharing behaviour of 10 captive Sumatran orang-utans and 18 chimpanzees, in situations where individuals could monopolize a sharable food source. We focused on communicative behaviours used to initiate food transfers, and assessed whether and how much food was transferred in response to these initiation attempts. In both species, most transfers were initiated by taking the food, resulting in passive sharing, while active sharing by offering food or after requesting it occurred only rarely. However, orang-utans differed from chimpanzees in several aspects. Because the food was mostly monopolized by the adult male, orang-utans attempted to initiate food transfers more frequently, resisted more to taking attempts, and were less likely to transfer whole food items. In both species, requests were less likely to result in food transfers, indicating that in situations involving access to food, they do not necessarily respond to ‘signals of need’. We argue that in addition to instances of active sharing, other factors such as the degree of food monopolization, response rates to ‘signals of need’, and the quality and quantity of transferred food need to be considered to gain a more detailed picture of prosociality across species.
%K active food sharing, chimpanzees, offer, prosocial behaviours, request, Sumatran orang-utans, taking
%J Animal Behaviour
%V 133
%& 91
%P 91 - 100
%@ 0003-3472