Animal Ecology, Utrecht University, Kruijt Gebouw, Second Floor, West Wing, Padualaan 8, 3584 CH Utrecht, The Netherlands.
J Acoust Soc Am. 2013 Sep;134(3):2326-35. doi: 10.1121/1.4817929.
One of the most apparent discontinuities between non-human primate (primate) call communication and human speech concerns repertoire size. The former is essentially fixed to a limited number of innate calls, while the latter essentially consists of numerous learned components. Consequently, primates are thought to lack laryngeal control required to produce learned voiced calls. However, whether they may produce learned voiceless calls awaits investigation. Here, a case of voiceless call learning in primates is investigated--orangutan (Pongo spp.) whistling. In this study, all known whistling orangutans are inventoried, whistling-matching tests (previously conducted with one individual) are replicated with another individual using original test paradigms, and articulatory and acoustic whistle characteristics are compared between three orangutans. Results show that whistling has been reported for ten captive orangutans. The test orangutan correctly matched human whistles with significantly high levels of performance. Whistle variation between individuals indicated voluntary control over the upper lip, lower lip, and respiratory musculature, allowing individuals to produce learned voiceless calls. Results are consistent with inter- and intra-specific social transmission in whistling orangutans. Voiceless call learning in orangutans implies that some important components of human speech learning and control were in place before the homininae-ponginae evolutionary split.
非人类灵长类（灵长类）的叫声交流与人类言语之间最明显的差异之一是曲目大小。前者本质上局限于有限数量的先天叫声，而后者本质上由众多习得的成分组成。因此，灵长类动物被认为缺乏产生习得的有声叫声所需的喉部控制。然而，它们是否可以产生习得的无声叫声仍有待研究。在这里，研究了灵长类动物的无声叫声学习案例——猩猩（Pongo spp.）吹口哨。在这项研究中，所有已知的吹口哨猩猩都被清点，使用原始测试范式，在另一个个体上重复以前与一个个体进行的吹口哨匹配测试，并比较了三个猩猩之间的发音和声学口哨特征。结果表明，有报道称十只圈养猩猩会吹口哨。测试猩猩以非常高的水平正确匹配了人类吹口哨。个体之间的口哨变化表明对上唇、下唇和呼吸肌有自主控制，使个体能够产生习得的无声叫声。结果与猩猩的种间和种内社会传播一致。猩猩的无声叫声学习意味着，在人类谱系-猩猩谱系的进化分裂之前，人类言语学习和控制的一些重要组成部分已经就位。
