Sperm Whales blow bubbles to achieve restful, vertical sleep
Sperm Whales blow bubbles to achieve restful, vertical sleep
抹香鲸通过喷出气泡实现垂直睡眠
Sperm Whales blow bubbles to achieve restful, vertical sleep. New research from the University of St Andrews and Université de Neuchâtel has uncovered the mechanism which allows sperm whales to sleep in a unique vertical position, just under the ocean surface. 抹香鲸通过喷出气泡来实现安稳的垂直睡眠。来自圣安德鲁斯大学（University of St Andrews）和纳沙泰尔大学（Université de Neuchâtel）的最新研究揭示了抹香鲸能够在海面下以独特的垂直姿势进行睡眠的机制。
Sperm whales are the only whale known to rest vertically. It’s thought to enable them to sleep effectively by buffering them from surface wave action, while avoiding the energy needed to dive to deeper depths. However, until now, it’s been unclear how they maintained their position just below the sea surface. 抹香鲸是目前已知唯一会垂直休息的鲸类。人们认为这种姿势能通过缓冲海面波浪的冲击，帮助它们更有效地睡眠，同时避免了潜入深海所需的能量消耗。然而，直到现在，人们还不清楚它们是如何保持在海面下这一位置的。
In a paper published today (23rd July) in the Journal of Experimental Biology, researchers discovered that while resting, sperm whales release gas bubbles to help them regulate their buoyancy and remain below the sea surface. This regulation is crucial as Sperm Whales are positively buoyant naturally due to the large amounts of spermaceti oil in their heads. 在今天（7月23日）发表于《实验生物学杂志》（Journal of Experimental Biology）的一篇论文中，研究人员发现，抹香鲸在休息时会释放气泡，以帮助调节浮力并保持在海面以下。这种调节至关重要，因为抹香鲸头部含有大量的鲸蜡油，使其天然具有正浮力。
Additionally, sperm whales are breath-hold divers; if they slowly drift up while resting, the gas in their lungs will slowly expand. Releasing bubbles enables them to counteract the expanding diving gas and achieve neutral buoyancy. 此外，抹香鲸是屏息潜水动物；如果它们在休息时缓慢上浮，肺部的气体就会缓慢膨胀。释放气泡使它们能够抵消膨胀的潜水气体，从而实现中性浮力。
Researchers were able to collect data by placing small tags using suction cups on Sperm Whales off the Norwegian coast. The tags record sound and 3-D animal movements. Clear bubble sounds were recorded by the tags, and animal movement data was used to create a simulation based on tissue density, drag through the water, and gas volumes in their body. 研究人员通过在挪威海岸附近的抹香鲸身上安装吸盘式小型标签，成功收集了数据。这些标签记录了声音和动物的3D运动轨迹。标签记录到了清晰的气泡声，研究人员利用动物运动数据，结合组织密度、水流阻力以及体内气体体积，创建了模拟模型。
Results from the simulation confirmed that the release of bubbles functioned to reduce the whales’ positive buoyancy, enabling them to remain submerged while resting. Additionally, the results indicate that sperm whales start resting dives with less diving gas volume than for deep foraging dives. 模拟结果证实，释放气泡的作用是降低鲸鱼的正浮力，使它们在休息时能够保持在水下。此外，研究结果还表明，抹香鲸在进行休息潜水时，其携带的潜水气体量比深海觅食潜水时要少。
Professor Patrick Miller from the Sea Mammal Research Unit at the University of St Andrews said: “This study confirms that Sperm Whales exquisitely control their buoyancy by releasing gases to remain submerged with near-neutral buoyancy just below the sea surface. It is particularly fascinating they are able to make these fine-scale adjustments while they are thought to be asleep, a challenge totally alien to terrestrial mammals like us humans.” 圣安德鲁斯大学海洋哺乳动物研究室的帕特里克·米勒（Patrick Miller）教授表示：“这项研究证实，抹香鲸通过释放气体来精确控制浮力，从而在海面下保持近乎中性的浮力并维持潜水状态。最令人着迷的是，它们在被认为处于睡眠状态时仍能进行这种精细的调整，这对我们人类这样的陆生哺乳动物来说是完全陌生的挑战。”
The authors suspect that releasing bubbles could be related to the off-gassing of excess CO2 or N2 from tissues into the lungs, so this behaviour could also have implications for metabolic gas exchange. 研究作者推测，释放气泡可能与组织中多余的二氧化碳或氮气排入肺部有关，因此这种行为可能对代谢气体交换也具有重要意义。