Gallup Andrew C, Miller Ralph R, Clark Anne B
Department of Biological Sciences, Binghamton University, Binghamton, New York 13902.
Ethology. 2010 Nov 21;116(2010):1-9. doi: 10.1111/j.1439-0310.2010.01854.x.
Yawning appears to be involved in arousal, state change, and activity across vertebrates. Recent research suggests that yawning may support effective changes in mental state or vigilance through cerebral cooling. To further investigate the relationship between yawning, state change, and thermoregulation, 12 Sprague-Dawley rats (Rattus norvegicus) were exposed to a total of two hours of ambient temperature manipulation over a period of 48 hours. Using a repeated measures design, each rat experienced a range of increasing (22→32°C), decreasing (32→22°C), and constant temperatures (22°C; 32°C). Yawning and locomotor activity occurred most frequently during initial changes in temperature, irrespective of direction, compared to more extended periods of temperature manipulation. The rate of yawning also diminished during constant high temperatures (32°C) compared to low temperatures (22°C). Unlike yawning, however, stretching was unaffected by ambient temperature variation. These findings are compared to recent work on budgerigars (Melopsittacus undulatus), and the ecological selective pressures for yawning in challenging thermal environments are discussed. The results support previous comparative research connecting yawning with arousal and state change, and contribute to refining the predictions of the thermoregulatory hypothesis across vertebrates.
打哈欠似乎与整个脊椎动物的觉醒、状态变化和活动有关。最近的研究表明，打哈欠可能通过脑部降温来支持精神状态或警觉性的有效变化。为了进一步研究打哈欠、状态变化和体温调节之间的关系，12只斯普拉格-道利大鼠（褐家鼠）在48小时内总共经历了两小时的环境温度操控。采用重复测量设计，每只大鼠都经历了一系列升温（22→32°C）、降温（32→22°C）和恒温（22°C；32°C）过程。与更长时间的温度操控相比，打哈欠和运动活动在温度最初变化期间出现得最为频繁，且与温度变化方向无关。与低温（22°C）相比，在持续高温（32°C）期间打哈欠的频率也会降低。然而，与打哈欠不同的是，伸展不受环境温度变化的影响。这些发现与最近关于虎皮鹦鹉（虎皮鹦鹉）的研究结果进行了比较，并讨论了在具有挑战性的热环境中打哈欠的生态选择压力。结果支持了先前将打哈欠与觉醒和状态变化联系起来的比较研究，并有助于完善对整个脊椎动物体温调节假说的预测。
