{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T14:27:05Z","timestamp":1786976825931,"version":"build-2736575974"},"reference-count":50,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2005,4,29]],"date-time":"2005-04-29T00:00:00Z","timestamp":1114732800000},"content-version":"vor","delay-in-days":3955,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American J Phys Anthropol"],"published-print":{"date-parts":[[1994,7]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    Orang\u2010utans (\n                    <jats:italic>Pongo pygmaeus<\/jats:italic>\n                    ) at the Singapore Zoological Gardens were presented with two thick\u2010shelled edible seeds,\n                    <jats:italic>Mezzettia parviflora<\/jats:italic>\n                    (Annonaceae) and\n                    <jats:italic>Macadamia ternifolia<\/jats:italic>\n                    (Proteaceae) in order to estimate their maximum bite forces. The orang\u2010utans could break the\n                    <jats:italic>Macadamia<\/jats:italic>\n                    seeds in one bite, while those of\n                    <jats:italic>Mezzettia<\/jats:italic>\n                    required repeated attempts. Examination of shell fragments showed that many had scratches and some had clear, but small (ca. 1\u20132 mm diameter), impressions on them. Building upon this information, semi\u2010imitative tests were performed on the seeds in a universal testing machine by loading them in compression with either flat plates or metal casts of orang\u2010utan cheek teeth. The maximum forces required to break the seeds were similar with both the flat plates and the metal teeth; the average for the\n                    <jats:italic>Macadamia<\/jats:italic>\n                    seeds being about 2,000 N (which forms a minimum estimate for the maximum bite forces in orang\u2010utans) and for the\n                    <jats:italic>Mezzettia<\/jats:italic>\n                    seeds, 6,000 N. The work done with the metal teeth was much greater than with the plates. A mechanical analysis showed that this extra work went into producing permanent impressions (\u201cbite marks\u201d) in the shell with the tooth cusps. These impressions were larger than those found on the shells of seeds bitten by the orang\u2010utans. Nevertheless, it is shown theoretically that the size of these indentations can give an estimate of the bite forces used. The maximum force developed in the machine tests with the metal teeth was correlated with the force calculated from analysis of the bite marks. The method is suitable for use in field studies where the marks left on remnants of hard foods eaten by primates may be used to estimate, very roughly, the forces used to produce them. \u00a9 1994 Wiley\u2010Liss, Inc.\n                  <\/jats:p>","DOI":"10.1002\/ajpa.1330940306","type":"journal-article","created":{"date-parts":[[2006,2,3]],"date-time":"2006-02-03T16:23:07Z","timestamp":1138983787000},"page":"365-378","source":"Crossref","is-referenced-by-count":89,"title":["Seed\u2010breaking forces exerted by orang\u2010utans with their teeth in captivity and a new technique for estimating forces produced in the Wild"],"prefix":"10.1002","volume":"94","author":[{"given":"Peter W.","family":"Lucas","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charles R.","family":"Peters","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stewart R.","family":"Arrandale","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2005,4,29]]},"reference":[{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/0003-9969(89)90024-1"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1038\/357360a0"},{"key":"e_1_2_1_4_1","unstructured":"ArrandaleS(1990)Forces Produced by Orang\u2010Utans with their Teeth. 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