科学家们 long wondered how and why fish swim in shoals and birds fly in flocks—what’s in it for the individuals? New research from New York University helps shed some light on what benefits they derive from their formations. (科学家们 long wondered how and why fish swim in shoals and birds fly in flocks—what’s in it for the individuals? New research from New York University helps shed some light on what benefits they derive from their formations。)
与陆地上依靠轮胎与地面摩擦前进的自行车手不同，鱼和鸟在运动时所处的介质（空气或水）是包围着它们的，而不仅仅是下方。它们基本上都是通过相似的机制在运动：纽约大学博士候选人、该研究的首席作者乔尔·纽波尔特（Joel Newbolt）称之为“拍打”。
此前的研究表明，“在鱼群和鸟群这样的群体中，你可以做到诸如减少在水中或空气中移动的能量消耗等事情，”纽波尔特说。这些移动方式使得鱼群和鸟群以特有的形状移动。其几何形状可能因物种而异——一群椋鸟的移动方式与一群加拿大雁的V形飞行方式不同——但两者都从它们的群体中获益。
在此前对这种行为的模型中，科学家们曾假设每条鱼或每只鸟都以完全相同的方式拍打，就像一群机器一样。但现实情况更为复杂：尽管世界上每一只鹅都与其他鹅不同，但所有加拿大雁群仍然以相似的队形飞行。
讽刺的是，这项最新研究的 शोधकर्ताओं actually used machines to model flapping in a controlled setting. They positioned two hydrofoils, a lifting surface designed to cut through liquid efficiently, in a tank of water. They lined the foils up one behind the other, and “flapped” both of them in a manner that parallels the general movement of a fish’s swimming tail or a bird’s flapping wings. What they found was that the lead hydrofoil created a wake behind it that “affects the position of the follower,” according to a supplementary video published by the researchers. That wake “can even keep the follower from colliding with, or separating from, the leader.” (该研究的 शोधकर्ताओं actually used machines to model flapping in a controlled setting. They positioned two hydrofoils, a lifting surface designed to cut through liquid efficiently, in a tank of water. They lined the foils up one behind the other, and “flapped” both of them in a manner that parallels the general movement of a fish’s swimming tail or a bird’s flapping wings. What they found was that the lead hydrofoil created a wake behind it that “affects the position of the follower,” according to a supplementary video published by the researchers. That wake “can even keep the follower from colliding with, or separating from, the leader。”)
这项实验“表明这些队形非常稳定，”未参与本研究的利哈伊大学的基思·穆尔德（Keith Moored）说。他的实验室也研究拍打。他说，这项研究进一步证实了鱼群或鸟群的形状是由它们周围的空气或水介质决定的，这些介质会对翅膀或鳍施加力。
但真正令人惊喜的发现是，即使在拍打方式有差异的情况下，水翼之间的关系——以及尾流的影响——也保持不变。利哈伊大学说：“我实际上对这一发现感到非常惊讶。这是一个全新的想法。”使它们保持相似的是水本身施加的力。在实验中，前部水翼留下的尾流决定了后部水翼保持的关系。它将后部水翼推开或拉近。
该团队希望，了解单个鱼类和鸟类如何成功地群体移动，也能为风能和水能等可再生能源技术的开发者提供启示。纽波尔特说：“根据河流的速度和它们的间距，后面的鱼或鸟可以获得更高的效率。”
但即使是动物本身，目前仍然充满神秘。“关于这些群体运动，确实还有很多需要理解的地方，”纽波尔特说。
