Taking the heat: thermoregulation in Asian elephants under different climatic conditions
Taking the heat: thermoregulation in Asian elephants under different climatic conditions
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吸收热量：不同气候条件下亚洲象的体温调节
DOI：
10.1007/s00360-011-0609-8
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
T. Ruf
中科院分区：
文献类型：
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作者：
Nicole M. Weissenböck;W. Arnold;T. Ruf
一些生活在沙漠环境中的哺乳动物（例如骆驼）通过在炎热的白天忍受体温（Tb）的升高，并在较凉爽的夜间散发多余的热量（即异温性）来应对高热负荷。由于体型较大有利于昼夜蓄热机制，因此我们研究了当亚洲象暴露在自然栖息地的温暖环境条件下时，这种反应是否也存在。我们比较了生活在泰国自然环境温度 (Ta) 下（平均 Ta ~ 30°C）的 11 只成年亚洲象和生活在德国较冷条件下（平均 Ta ~ 21°C）的 6 只亚洲象的肠道结核菌每日周期。泰国大象的平均每日 Tb 波动范围 (1.15°C) 明显大于德国饲养的大象 (0.51°C)。这是因为白天最大 Tb 增加，而深夜最小 Tb 减少。随着 Ta 的增加，大象的最低 Tb 每天都会降低，因此进入一天时，大象会拥有额外热量储存的热储备，这与干旱地区的有蹄类动物非常相似。我们得出的结论是，这些反应显示了异温性的所有特征，并且这种体温调节策略不仅限于沙漠哺乳动物，亚洲象也采用了。
Some mammals indigenous to desert environments, such as camels, cope with high heat load by tolerating an increase in body temperature (Tb) during the hot day, and by dissipating excess heat during the cooler night hours, i.e., heterothermy. Because diurnal heat storage mechanisms should be favoured by large body size, we investigated whether this response also exists in Asian elephants when exposed to warm environmental conditions of their natural habitat. We compared daily cycles of intestinal Tb of 11 adult Asian elephants living under natural ambient temperatures (Ta) in Thailand (mean Ta ~ 30°C) and in 6 Asian elephants exposed to cooler conditions (mean Ta ~ 21°C) in Germany. Elephants in Thailand had mean daily ranges of Tb oscillations (1.15°C) that were significantly larger than in animals kept in Germany (0.51°C). This was due to both increased maximum Tb during the day and decreased minimum Tb at late night. Elephant’s minimum Tb lowered daily as Ta increased and hence entered the day with a thermal reserve for additional heat storage, very similar to arid-zone ungulates. We conclude that these responses show all characteristics of heterothermy, and that this thermoregulatory strategy is not restricted to desert mammals, but is also employed by Asian elephants.