Lucas P W, Peters C R, Arrandale S R
Department of Anatomy, University of Hong Kong.
Am J Phys Anthropol. 1994 Jul;94(3):365-78. doi: 10.1002/ajpa.1330940306.
Orang-utans (Pongo pygmaeus) at the Singapore Zoological Gardens were presented with two thick-shelled edible seeds, Mezzettia parviflora (Annonaceae) and Macadamia ternifolia (Proteaceae) in order to estimate their maximum bite forces. The orang-utans could break the Macadamia seeds in one bite, while those of Mezzettia required repeated attempts. Examination of shell fragments showed that many had scratches and some had clear, but small (ca. 1-2 mm diameter), impressions on them. Building upon this information, semi-imitative 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-utan 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 Macadamia seeds being about 2,000 N (which forms a minimum estimate for the maximum bite forces in orang-utans) and for the Mezzettia 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 ("bite marks") in the shell with the tooth cusps. These impressions were larger than those found on the shells of seeds bitten by the orang-utans. Nevertheless, it is shown theoretically that the size of these indentations can given 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.
为了估算新加坡动物园的红毛猩猩（Pongo pygmaeus）的最大咬合力，研究人员向它们展示了两种厚壳可食用种子，小花肉豆蔻（Mezzettia parviflora，番荔枝科）和澳洲坚果（Macadamia ternifolia，山龙眼科）。红毛猩猩一口就能咬开澳洲坚果的种子，而咬开小花肉豆蔻的种子则需要反复尝试。对种子壳碎片的检查发现，许多碎片上有划痕，有些还有清晰但很小（直径约1 - 2毫米）的凹痕。基于这些信息，研究人员在万能试验机上对种子进行了半模拟测试，用平板或红毛猩猩颊齿的金属铸件对种子进行压缩加载。用平板和金属齿咬开种子所需的最大力相似；澳洲坚果种子的平均咬合力约为2000牛（这是红毛猩猩最大咬合力的最低估计值），小花肉豆蔻种子的平均咬合力为6000牛。使用金属齿时所做的功比使用平板时要大得多。力学分析表明，这些额外的功用于在种子壳上产生由齿尖造成的永久凹痕（“咬痕”）。这些凹痕比红毛猩猩咬过的种子壳上的凹痕要大。然而，从理论上表明，这些凹痕的大小可以用来估计所使用的咬合力。在机器测试中使用金属齿产生的最大力与根据咬痕分析计算出的力相关。该方法适用于野外研究，在野外，灵长类动物食用的硬食物残渣上留下的痕迹可用于非常粗略地估计产生这些痕迹所使用 的力。
