Pillay Praneshri, Manger Paul R
School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa.
J Sleep Res. 2004 Dec;13(4):353-8. doi: 10.1111/j.1365-2869.2004.00419.x.
Cetacean sleep phenomenology consists of a combination of unihemispheric slow wave sleep and a massive reduction in the amount of rapid eye movement sleep. Despite various proposals, the selection pressure driving the evolution of this combined sleep phenomenology is unknown. It was recently suggested that the need to produce heat in the thermally challenging aquatic environment might have been the selection pressure. Mechanisms of heat loss and heat production can be measured directly or indirectly. The present study was designed to test the thermogenetic proposal by recording indirect measurements of heat loss (surface area to volume ratio) and heat production (tail-beats per minute). A strong correlation was found between these two parameters, such that increases in potential heat loss were matched by increases in potential heat production. This result suggests that the need to compensate for heat loss can provide an evolutionary rationale for the appearance of extant cetacean sleep physiology.
鲸类睡眠现象学由单侧脑慢波睡眠和快速眼动睡眠量的大幅减少组成。尽管有各种提议，但驱动这种复合睡眠现象学进化的选择压力尚不清楚。最近有人提出，在具有热挑战的水生环境中产生热量的需求可能是选择压力。热量损失和热量产生的机制可以直接或间接测量。本研究旨在通过记录热量损失（表面积与体积比）和热量产生（每分钟摆尾次数）的间接测量来测试产热假说。发现这两个参数之间存在很强的相关性，即潜在热量损失的增加与潜在热量产生的增加相匹配。这一结果表明，补偿热量损失的需求可以为现存鲸类睡眠生理学的出现提供一个进化原理。
