Thompson Cynthia L, Scheidel Caleb, Glander Kenneth E, Williams Susan H, Vinyard Christopher J
Department of Biomedical Sciences, Grand Valley State University, 1 N Campus Drive, Allendale, MI 49401, USA.
Department of Biomedical Sciences, Grand Valley State University, 1 N Campus Drive, Allendale, MI 49401, USA.
J Therm Biol. 2017 Jan;63:49-57. doi: 10.1016/j.jtherbio.2016.11.005. Epub 2016 Nov 16.
Infrared thermography has become a useful tool to assess surface temperatures of animals for thermoregulatory research. However, surface temperatures are an endpoint along the body's core-shell temperature gradient. Skin and fur are the peripheral tissues most exposed to ambient thermal conditions and are known to serve as thermosensors that initiate thermoregulatory responses. Yet relatively little is known about how surface temperatures of wild mammals measured by infrared thermography relate to subcutaneous temperatures. Moreover, this relationship may differ with the degree that fur covers the body. To assess the relationship between temperatures and temperature gradients in peripheral tissues between furred and bare areas, we collected data from wild mantled howling monkeys (Alouatta palliata) in Costa Rica. We used infrared thermography to measure surface temperatures of the furred dorsum and bare facial areas of the body, recorded concurrent subcutaneous temperatures in the dorsum, and measured ambient thermal conditions via a weather station. Temperature gradients through cutaneous tissues (subcutaneous-surface temperature) and surface temperature gradients (surface-ambient temperature) were calculated. Our results indicate that there are differences in temperatures and temperature gradients in furred versus bare areas of mantled howlers. Under natural thermal conditions experienced by wild animals, the bare facial areas were warmer than temperatures in the furred dorsum, and cutaneous temperature gradients in the face were more variable than the dorsum, consistent with these bare areas acting as thermal windows. Cutaneous temperature gradients in the dorsum were more closely linked to subcutaneous temperatures, while facial temperature gradients were more heavily influenced by ambient conditions. These findings indicate that despite the insulative properties of fur, for mantled howling monkeys surface temperatures of furred areas still demonstrate a relationship with subcutaneous temperatures. Given that most mammals possess dense fur, this provides insight for using infrared imaging in thermoregulatory studies of wild animals lacking bare skin.
红外热成像已成为评估动物体表温度以进行体温调节研究的有用工具。然而，体表温度是沿着身体核心 - 外壳温度梯度的一个终点。皮肤和毛发是最易暴露于环境热条件的外周组织，并且已知它们作为启动体温调节反应的热传感器。然而，关于通过红外热成像测量的野生哺乳动物体表温度与皮下温度之间的关系，我们所知相对较少。此外，这种关系可能会因毛发覆盖身体的程度而有所不同。为了评估有毛区域和无毛区域外周组织中的温度及温度梯度之间的关系，我们从哥斯达黎加的野生长毛吼猴（Alouatta palliata）收集了数据。我们使用红外热成像测量身体有毛背部和裸露面部区域的体表温度，记录背部同时的皮下温度，并通过气象站测量环境热条件。计算了通过皮肤组织的温度梯度（皮下 - 体表温度）和体表温度梯度（体表 - 环境温度）。我们的结果表明，长毛吼猴有毛区域和无毛区域的温度及温度梯度存在差异。在野生动物所经历的自然热条件下，裸露的面部区域比有毛背部的温度更高，并且面部的皮肤温度梯度比背部更具变化性，这与这些裸露区域充当热窗的情况一致。背部的皮肤温度梯度与皮下温度的联系更为紧密，而面部温度梯度受环境条件的影响更大。这些发现表明，尽管毛发具有隔热特性，但对于长毛吼猴来说，有毛区域的体表温度仍与皮下温度存在关联。鉴于大多数哺乳动物都有浓密的毛发，这为在缺乏裸露皮肤的野生动物体温调节研究中使用红外成像提供了见解。
