Boyles Justin G, Bennett Nigel C, Mohammed Osama B, Alagaili Abdulaziz N
1 Cooperative Wildlife Research Laboratory, Department of Zoology, Southern Illinois University, Carbondale, Illinois.
2 King Saud University Mammals Research Chair, Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
Physiol Biochem Zool. 2017 Jul/Aug;90(4):445-452. doi: 10.1086/691542.
Documenting variation in thermoregulatory patterns across phylogenetically and geographically diverse taxa is key to understanding the evolution of endothermy and heterothermy in birds and mammals. We recorded body temperature (T) in free-ranging desert hedgehogs (Paraechinus aethiopicus) across three seasons in the deserts of Saudi Arabia. Modal T's (35°-36.5°C) were slightly below normal for mammals but still warmer than those of other hedgehogs. The single maximum T recorded was 39.2°C, which is cooler than maximum T's recorded in most desert mammals. Desert hedgehogs commonly used torpor during winter and spring but never during summer. Torpor bouts occurred frequently but irregularly, and most lasted less than 24 h. Unlike daily heterotherms, desert hedgehogs did occasionally remain torpid for more than 24 h, including one bout of 101 h. Body temperatures during torpor were often within 2°-3°C of ambient temperature; however, we never recorded repeated bouts of long, predictable torpor punctuated by brief arousal periods similar to those common among seasonal hibernators. Thus, desert hedgehogs can be included on the ever-growing list of species that display torpor patterns intermediate to traditionally defined hibernators and daily heterotherms. Extant hedgehogs are a recent radiation within an ancient family, and the intermediate thermoregulatory pattern displayed by desert hedgehogs is unlike the deeper and more regular torpor seen in other hedgehogs, suggesting that this may be a derived-as opposed to ancestral-trait in this subfamily. We suggest that this family (Erinaceidae) and order (Eulipotyphla) may be important for understanding the evolution of thermoregulatory patterns among Laurasiatheria and mammals in general.
记录系统发育和地理分布上不同类群的体温调节模式变化，是理解鸟类和哺乳动物恒温性和异温性进化的关键。我们在沙特阿拉伯沙漠中，对自由放养的沙漠刺猬（Paraechinus aethiopicus）进行了三个季节的体温记录。其体温模式（35°-36.5°C）略低于哺乳动物的正常体温，但仍高于其他刺猬。记录到的最高体温为39.2°C，比大多数沙漠哺乳动物的最高体温要低。沙漠刺猬在冬季和春季常进入蛰伏状态，但夏季从不蛰伏。蛰伏发作频繁但无规律，大多数持续时间不到24小时。与每日异温动物不同，沙漠刺猬偶尔会蛰伏超过24小时，其中一次长达101小时。蛰伏期间的体温通常在环境温度的2°-3°C范围内；然而，我们从未记录到像季节性冬眠动物那样，由短暂觉醒期打断的长时间、可预测的反复蛰伏发作。因此，沙漠刺猬可被列入不断增加的物种名单中，这些物种表现出介于传统定义的冬眠动物和每日异温动物之间的蛰伏模式。现存的刺猬是一个古老家族中近期分化出来的类群，沙漠刺猬表现出的中间体温调节模式与其他刺猬更深且更规律的蛰伏不同，这表明这可能是该亚科的一种衍生特征，而非祖先特征。我们认为，这个家族（猬科）和目（真盲缺目）对于理解劳亚兽总目乃至整个哺乳动物的体温调节模式进化可能很重要。
