O'Malley R C, McGrew W C
Miami University, Oxford, Ohio, USA.
Folia Primatol (Basel). 2000 Sep-Oct;71(5):334-41. doi: 10.1159/000021756.
Eight captive orangutans (Pongo pygmaeus) were given wooden blocks embedded with raisins and bamboo as raw material for tool making in a study of manual laterality. In about three quarters of the raisin extraction bouts, the orangutans held the tool in the lips or teeth rather than in their hands. Three adult males and 2 adult females showed extreme (> or =92%) preference for oral tool use, a subadult male and an adult female used oral tools about half the time, and 1 adult female preferred manual tool use. Most oral tool users made short tools (approx. 4-10 cm long) that were held in the lips and (probably) supported by the tongue. Preference for oral tool use does not correlate with body weight, age or sex, but it may be related to hand size or individual preference. This is the first report of customary oral tool use as the norm in captive orangutans; it resembles the behavioral patterns reported by van Schaik et al. and Fox et al. in nature.
在一项关于用手偏好的研究中，八只圈养的红毛猩猩（婆罗洲猩猩）被给予嵌入葡萄干的木块和竹子作为制作工具的原材料。在大约四分之三的提取葡萄干的过程中，红毛猩猩是用嘴唇或牙齿夹住工具，而不是用手。三只成年雄性和两只成年雌性表现出对使用口腔工具的极端偏好（≥92%），一只亚成年雄性和一只成年雌性大约一半时间使用口腔工具，还有一只成年雌性更喜欢使用手动工具。大多数使用口腔工具的红毛猩猩制作的是短工具（大约4 - 10厘米长），这些工具被夹在嘴唇中（可能）由舌头支撑。对使用口腔工具的偏好与体重、年龄或性别无关，但可能与手的大小或个体偏好有关。这是关于圈养红毛猩猩习惯性地将使用口腔工具作为常态的首次报告；它类似于范·沙伊克等人和福克斯等人在自然环境中所报告的行为模式。
