The distribution of the koala (Phascolarctos cinereus) in Queensland is predicted to contract as a result of climate change, driven by the frequency, intensity and duration of heatwaves and drought. However, little is known about the physiological responses of this species to environmental extremes under field conditions. This study aimed to establish the efficacy of surgically implanted thermal radio transmitters and data loggers to measure the body temperature of free-ranging koalas across a range of environmental conditions and ambient temperatures. Five free-ranging koalas in southeast Queensland were implanted with thermal transmitters and data loggers waxed together as a single package. Body temperatures were recorded for variable periods ranging from 3 to 12 months. Diurnal rhythms in body temperature were detected irrespective of season. The long-term diurnal body temperature peak for all koalas occurred between 16:00 and 17:00 h and body temperature was 36.7–36.9 °C, the long-term nadir occurred between 07:00 and 08:00 h and body temperature was 35.4–35.7 °C. Koala body temperatures as low as 34.2 °C and as high as 39.0 °C were recorded. Thermolability became apparent when ambient temperatures were outside the deduced thermal neutral zone for koalas (14.5–24.5 °C): heat was accumulated during the day and dissipated during the cool of the night. While this study is the first to report on body temperature of free-ranging koalas in their normal behavioural context, further investigations are necessary to determine the physiological boundaries of the thermal niche for this species, in order to better equip models that will more accurately predict the impacts of climate change on koalas.

中文翻译：

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昆士兰东南部自由放养考拉 (Phascolarctos cinereus) 的体温

由于气候变化，受热浪和干旱的频率、强度和持续时间的影响，昆士兰考拉 (Phascolarctos cinereus) 的分布预计将缩小。然而，关于该物种在野外条件下对极端环境的生理反应知之甚少。本研究旨在确定通过手术植入的热无线电发射器和数据记录器在一系列环境条件和环境温度下测量自由放养考拉的体温的功效。昆士兰东南部的五只自由放养的考拉被植入了热发射器和数据记录器，这些热传感器和数据记录器作为一个单独的包裹被植入在一起。在 3 至 12 个月的不同时期内记录体温。无论季节如何，都检测到体温的昼夜节律。所有考拉的长期昼夜体温峰值出现在 16:00 至 17:00 h 之间，体温为 36.7-36.9 °C，长期最低点出现在 07:00 至 08:00 h 之间，体温为35.4–35.7 °C。考拉的体温低至 34.2 °C，最高可达 39.0 °C。当环境温度超出推导出的考拉热中性区（14.5-24.5°C）时，热稳定性变得明显：热量在白天积累，在夜间凉爽时消散。虽然这项研究首次报告了自由放养考拉在正常行为环境下的体温，但需要进一步调查以确定该物种热生态位的生理边界，