Bicca-Marques J C, Calegaro-Marques C
Department of Anthropology, University of Illinois, Urbana 61801, USA.
Am J Phys Anthropol. 1998 Aug;106(4):533-46. doi: 10.1002/(SICI)1096-8644(199808)106:4<533::AID-AJPA8>3.0.CO;2-J.
Behavioral thermoregulation in primates may provide a means for the conservation of heat during periods of low ambient temperature and/or food shortage as well as a way to dissipate heat under hot conditions. This article focuses on behavioral thermoregulation in a sexually dichromatic primate, the black-and-gold howling monkey (Alouatta caraya). Two models have been proposed to explain the evolution of sexual dichromatism in this species: thermoregulation and sexual selection. Five hypotheses associated with thermoregulatory behaviors are tested. These are as follows: (1) energy-conserving postures are used mainly under low ambient temperatures; (2) sunny resting places are selected during periods of low temperature; (3) exposure of the less-insulated ventral region to sunlight decreases with increasing temperature; (4) black-colored adult males use energy-conserving postures, sunny places, and exposure of the ventral region to sunlight less frequently than do blonde-colored adult females; and (5) smaller individuals use energy-conserving postures, sunny places, and exposure of the ventral region to sunlight in significantly greater frequency than do larger individuals. Over a 12-month period, behavioral data were collected on a free-ranging habituated group of 15-17 howlers of all age-sex classes. Ambient temperature was measured each hour. The results indicate that during resting, howlers showed a consistent use of heat-conserving postures, showed a preference for sunny places, and exposed their ventral region to sunlight under low ambient temperatures. A preference for shady places, heat-dissipating postures, and exposure of the back were observed under high ambient temperatures. Despite sex differences in adult color patterns and differences in size between age classes, no significant age or sex differences in thermoregulatory behaviors were detected. Failure to confirm a thermoregulation model implies that sexual selection may be responsible for sexual dichromatism in this species.
灵长类动物的行为体温调节可能是在环境温度低和/或食物短缺期间保存热量的一种方式，也是在炎热条件下散热的一种途径。本文聚焦于一种具有性别二态性的灵长类动物——黑金吼猴（Alouatta caraya）的行为体温调节。已经提出了两种模型来解释该物种性别二态性的进化：体温调节和性选择。对与体温调节行为相关的五个假说进行了检验。具体如下：（1）节能姿势主要在环境温度低时使用；（2）在低温时期选择阳光充足的休息场所；（3）随着温度升高，隔热性较差的腹部暴露在阳光下的情况减少；（4）黑色成年雄性比金色成年雌性更少使用节能姿势、阳光充足的地方以及将腹部暴露在阳光下；（5）体型较小的个体比体型较大的个体更频繁地使用节能姿势、阳光充足的地方以及将腹部暴露在阳光下。在12个月的时间里，收集了一个由15 - 17只各年龄 - 性别类别的自由放养且习惯化的吼猴群体的行为数据。每小时测量环境温度。结果表明，在休息时，吼猴一贯使用保存热量的姿势，偏好阳光充足的地方，并且在环境温度低时将腹部暴露在阳光下。在环境温度高时，观察到它们偏好阴凉的地方、散热姿势以及背部暴露在外。尽管成年个体的颜色模式存在性别差异以及不同年龄组之间存在体型差异，但未检测到体温调节行为存在显著的年龄或性别差异。未能证实体温调节模型意味着性选择可能是该物种性别二态性的原因。
