Cannon C H, Leighton M
Department of Anthropology, Harvard University, Cambridge, Massachusetts 02138.
Am J Phys Anthropol. 1994 Apr;93(4):505-24. doi: 10.1002/ajpa.1330930409.
To examine functional questions of arboreal locomotor ecology, the selection of canopy elements by Bornean agile gibbons (Hylobates agilis) and long-tailed macaques (Macaca fascicularis) was contrasted, and related to locomotor behaviors. The two species, and in some cases, the macaque sexes, varied in their use of most structural elements. Although both species traveled most frequently in the main canopy layer (macaques: 56%, gibbons: 48%), the gibbons strongly preferred the emergent canopy layer and traveled higher than the macaques (31 vs. 23 m above ground) in larger trees (48 vs. 26 cm dbh). Macaques preferred to cross narrower gaps (50% were in the class 0.1-0.5 m wide) than gibbons (42% were 1.6-3.0 m wide), consistent with the maximum gap width each crossed (3.5 m for macaques, 9 m for gibbons). Macaques could cross only 12% of the gaps encountered in the main canopy, and < 5% of the gaps in each of the other four layers. In contrast, all layers appear relatively continuous for gibbons. Specialized locomotor modes were used disproportionately at the beginning and end of travel segments, further indicating that behavior was organized around gap crossings. A model is defined, the Perceived Continuity Index (PCI), which predicts the relative use of canopy strata for each species, based on the percentage of gaps a species can cross, the frequency of gaps, and median length of continuous canopy structure in each canopy layer. The results support the hypothesis that locomotor behaviors, and strategies of selecting canopy strata for travel, are strongly constrained by wide gaps between trees and are ultimately based on selection for efficient direct line travel between distant points.
为了研究树栖运动生态学的功能问题，对婆罗洲白手长臂猿（敏捷长臂猿）和食蟹猴选择树冠元素的情况进行了对比，并将其与运动行为相关联。这两个物种，在某些情况下食蟹猴的不同性别，在大多数结构元素的使用上存在差异。尽管两个物种在主树冠层活动最为频繁（食蟹猴：56%，长臂猿：48%），但长臂猿强烈偏好树冠顶层，且在更大的树木（胸径48厘米对26厘米）中活动高度高于食蟹猴（离地面31米对23米）。食蟹猴更喜欢跨越比长臂猿更窄的间隙（50%的间隙宽度在0.1 - 0.5米之间），这与它们各自跨越的最大间隙宽度一致（食蟹猴为3.5米，长臂猿为9米）。食蟹猴只能跨越主树冠层中遇到的12%的间隙，以及其他四层中每层不到5%的间隙。相比之下，对长臂猿来说所有层看起来相对连续。在行程段的开始和结束时，专门的运动模式使用比例过高。这进一步表明行为是围绕间隙跨越而组织的。定义了一个模型，即感知连续性指数（PCI），它基于一个物种能够跨越的间隙百分比、间隙频率以及每个树冠层中连续树冠结构的中位数长度，预测每个物种对树冠层的相对利用情况。结果支持了这样的假设，即运动行为以及选择树冠层进行移动的策略，受到树木间宽间隙的强烈限制，并且最终基于对远距离高效直线移动的选择。
