<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bandini, Elisa</style></author><author><style face="normal" font="default" size="100%">Grossmann, Johannes</style></author><author><style face="normal" font="default" size="100%">Funk, Martina</style></author><author><style face="normal" font="default" size="100%">Albiach-Serrano, Anna</style></author><author><style face="normal" font="default" size="100%">Tennie, Claudio</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Naïve orangutans (Pongo abelii and Pongo pygmaeus) individually acquire nut-cracking using hammer tools</style></title><secondary-title><style face="normal" font="default" size="100%">American Journal of Primatology</style></secondary-title><short-title><style face="normal" font="default" size="100%">American Journal of Primatology</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">individual learning</style></keyword><keyword><style  face="normal" font="default" size="100%">nut-cracking</style></keyword><keyword><style  face="normal" font="default" size="100%">Orangutan</style></keyword><keyword><style  face="normal" font="default" size="100%">Social learning</style></keyword><keyword><style  face="normal" font="default" size="100%">tool-use</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2021</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2021/08/11</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://onlinelibrary.wiley.com/doi/10.1002/ajp.23304</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">n/a</style></volume><pages><style face="normal" font="default" size="100%">e23304</style></pages><isbn><style face="normal" font="default" size="100%">0275-2565</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Abstract Nut-cracking with hammer tools (henceforth: nut-cracking) has been argued to be one of the most complex tool-use behaviors observed in nonhuman animals. So far, only chimpanzees, capuchins, and macaques have been observed using tools to crack nuts in the wild (Boesch and Boesch,&amp;nbsp;1990; Gumert et al.,&amp;nbsp;2009; Mannu and Ottoni,&amp;nbsp;2009). However, the learning mechanisms behind this behavior, and the extent of nut-cracking in other primate species are still unknown. The aim of this study was two-fold. First, we investigated whether another great ape species would develop nut-cracking when provided with all the tools and appropriate conditions to do so. Second, we examined the mechanisms behind the emergence of nut-cracking by testing a naïve sample. Orangutans (Pongo abelii and Pongo pygmaeus) have the second most extensive tool-use repertoire among the great apes (after chimpanzees) and show flexible problem-solving capacities. Orangutans have not been observed cracking nuts in the wild, however, perhaps because their arboreal habits provide limited opportunities for nut-cracking. Therefore, orangutans are a valid candidate species for the investigation of the development of this behavior. Four nut-cracking-naïve orangutans at Leipzig zoo (P. abelii; Mage?=?16; age range?=?10?19; 4F; at the time of testing) were provided with nuts and hammers but were not demonstrated the nut-cracking behavioral form. Additionally, we report data from a previously unpublished study by one of the authors (Martina Funk) with eight orangutans housed at Zürich zoo (six P. abelii and two P. pygmaeus; Mage?=?14; age range?=?2?30; 5F; at the time of testing) that followed a similar testing paradigm. Out of the twelve orangutans tested, at least four individuals, one from Leipzig (P. abelii) and three from Zürich (P. abelii&amp;nbsp;and P. pygmaeus), spontaneously expressed nut-cracking using wooden hammers. These results demonstrate that nut-cracking can emerge in orangutans through individual learning and certain types of non-copying social learning.&lt;/p&gt;
</style></abstract><issue><style face="normal" font="default" size="100%">n/a</style></issue><notes><style face="normal" font="default" size="100%">&lt;p&gt;https://doi.org/10.1002/ajp.23304&lt;/p&gt;
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