Fat head: an analysis of head and neck insulation in the leatherback turtle (Dermochelys coriacea)
Fat head: an analysis of head and neck insulation in the leatherback turtle (Dermochelys coriacea)
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DOI：
10.1242/jeb.026500
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发表时间：
2009-09-01
影响因子：
2.8
通讯作者：
Cuffe, Tracy
中科院分区：
文献类型：
--
作者：
Davenport, John;Fraher, John;Cuffe, Tracy
成年棱皮龟在寒冷的温带水域觅食时是巨大的恒温/吸热动物，尽管潜水时遇到的表面温度约为15摄氏度，温度低至0.4摄氏度，但其主体腔内的核心体温仍保持在25摄氏度左右。棱皮龟也吃大量的冷的、凝胶状的猎物（水母和火虫）。我们假设棱皮龟的头部和颈部的结构特征可以最大限度地减少头部的热量损失，并限制头部和颈部在进食时的冷却。通过对防腐标本的大体解剖和分析性计算机断层扫描（通过地面真实解剖验证），我们证实了这一预测。头颈部脂肪组织占比21%。它以颅内脂肪的形式出现，包裹着盐腺、眼球的中间部分、以及神经颅骨和大脑。颈部的背侧表面有厚厚的鲸脂垫，颈动脉和颈静脉深埋于颈部，并在侧面被鲸脂保护。食道被脂肪组织的厚鞘所包围，而口咽腔与颚骨部分之间有脂肪层，为盐腺和神经头盖骨提供进一步的腹侧绝缘。
Adult leatherback turtles are gigantothermic/endothermic when foraging in cool temperate waters, maintaining a core body temperature within the main body cavity of ca. 25 degrees C despite encountering surface temperatures of ca. 15 degrees C and temperatures as low as 0.4 degrees C during dives. Leatherbacks also eat very large quantities of cold, gelatinous prey (medusae and pyrosomas). We hypothesised that the head and neck of the leatherback would have structural features to minimise cephalic heat loss and limit cooling of the head and neck during food ingestion. By gross dissection and analytical computed tomography ( validated by ground truthing dissection) of an embalmed specimen we confirmed this prediction. 21% of the head and neck was occupied by adipose tissue. This occurred as intracranial blubber, encapsulating the salt glands, medial portions of the eyeballs, plus the neurocranium and brain. The dorsal and lateral surfaces of the neck featured thick blubber pads whereas the carotid arteries and jugular veins were deeply buried in the neck and protected laterally by blubber. The oesophagus was surrounded by a thick sheath of adipose tissue whereas the oropharyngeal cavity had an adipose layer between it and the bony proportion of the palate, providing further ventral insulation for salt glands and neurocranium.