Brain Function Research Group, School of Physiology, Medical School, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa.
J Comp Physiol B. 2010 Oct;180(7):1111-9. doi: 10.1007/s00360-010-0480-z. Epub 2010 May 26.
Heterothermy, a variability in body temperature beyond the limits of homeothermy, has been advanced as a key adaptation of Arabian oryx (Oryx leucoryx) to their arid-zone life. We measured body temperature using implanted data loggers, for a 1-year period, in five oryx free-living in the deserts of Saudi Arabia. As predicted for adaptive heterothermy, during hot months compared to cooler months, not only were maximum daily body temperatures higher (41.1 ± 0.3 vs. 39.7 ± 0.1°C, P = 0.0002) but minimum daily body temperatures also were lower (36.1 ± 0.3 vs. 36.8 ± 0.2°C, P = 0.04), resulting in a larger daily amplitude of the body temperature rhythm (5.0 ± 0.5 vs. 2.9 ± 0.2°C, P = 0.0007), while mean daily body temperature rose by only 0.4°C. The maximum daily amplitude of the body temperature rhythm reached 7.7°C for two of our oryx during the hot-dry period, the largest amplitude ever recorded for a large mammal. Body temperature variability was influenced not only by ambient temperature but also water availability, with oryx displaying larger daily amplitudes of the body temperature rhythm during warm-dry months compared to warm-wet months (3.6 ± 0.6 vs. 2.3 ± 0.3°C, P = 0.005), even though ambient temperatures were the same. Free-living Arabian oryx therefore employ heterothermy greater than that recorded in any other large mammal, but water limitation, rather than high ambient temperature, seems to be the primary driver of this heterothermy.
异温性，即体温超出恒温范围的可变性，被认为是阿拉伯大羚羊（Oryx leucoryx）适应干旱环境的关键适应性特征之一。我们使用植入式数据记录仪对 5 只在沙特阿拉伯沙漠中自由生活的大羚羊进行了为期 1 年的体温测量。正如对适应性异温性的预测那样，与较凉爽的月份相比，在炎热的月份中，大羚羊的最高日体温不仅更高（41.1 ± 0.3 对 39.7 ± 0.1°C，P = 0.0002），最低日体温也更低（36.1 ± 0.3 对 36.8 ± 0.2°C，P = 0.04），导致体温节律的日振幅更大（5.0 ± 0.5 对 2.9 ± 0.2°C，P = 0.0007），而平均日体温仅升高 0.4°C。在炎热干燥期，我们的 2 只大羚羊的体温日振幅最高达到 7.7°C，这是大型哺乳动物中记录到的最大振幅。体温的变异性不仅受环境温度的影响，还受水供应的影响，与温暖湿润月份相比，在温暖干燥月份中，大羚羊的体温节律日振幅更大（3.6 ± 0.6 对 2.3 ± 0.3°C，P = 0.005），尽管环境温度相同。因此，自由生活的阿拉伯大羚羊表现出比任何其他大型哺乳动物都更大的异温性，但似乎是水限制而不是高环境温度是这种异温性的主要驱动因素。
