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Windows Vex¹ Bats' Echolocating Abilities

干扰蝙蝠回声定位的烦人窗

Just as humans understand the shape of our surroundings by how light reflects off objects, bats use reflections of sounds they produce instead—what’s called echolocation. But despite their excellent sensing abilities, one type of obstacle vexes² the animals: smooth vertical³ surfaces, like windows. Because windows reflect almost all the bats’ calls away from bats at an angle—creating the illusion of empty space.

正如人类会通过光对物体的反射来了解周围的环境状况一样，蝙蝠也会利用回声波来进行回声定位。不过，虽然它们拥有极强的感知能力，但有一种障碍物却令它们非常无奈，那就是光滑的垂直面，比如窗户。因为在某一角度上窗户会反射开几乎所有蝙蝠的声音，从而创造出一种真空区的错觉。

"To better understand it you can actually use a visual analogy." Stefan Greif, a sensory⁴ ecologist at the Max Planck Institute for Ornithology⁵. Imagine standing⁶ in a dark room, he says, beside a mirror. "If then if you take a flashlight in your hand and shine it on the side onto this mirror, you would see that all the light is reflected away. You'd see it on the other side of the wall. So even visually this would look to you like there's a hole in the wall. There's nothing coming back from this place."

“你可以利用视觉类比来更好地理解这种现象。”马克斯·普朗克鸟类研究所的感官生态学家斯特凡?格雷夫说道。他说，你可以想象自己在一个黑暗的房间里，站在一面镜子的旁边。“然后，如果你拿起手电筒照在镜子上，你就会看到所有的光都被反射出去了。你会看到光打到了墙的另一边。所以即使从视觉角度看，你也会觉得墙上有个洞。这里不会反射任何东西。”

Light wouldn't come back to you unless you aimed the flashlight more or less perpendicular⁷ to the mirror—and same for bats and their calls. This perceptual glitch⁸ meant that in lab tests 90 percent of bats banged into a smooth vertical surface. (And by the way, the researchers say that none were hurt.) But here's the interesting bit: bats never smashed into a smooth horizontal surface.

除非你或多或少调整手电筒光的方向使其垂直于镜子。这就跟蝙蝠和它们的叫声一样。这种感知故障意味着，在实验室测试中90%的蝙蝠会撞到光滑的垂直表面。(特别说明，研究人员表示试验中没有蝙蝠受伤。) 但有趣的是：蝙蝠从来不会撞到光滑的水平面。

Greif says that's because plenty of horizontal planes exist in nature, like lakes and ponds. And even though a lake reflects calls away from the bat, bats have evolved to perceive the absence of sound reflections from horizontal surfaces as water. In fact previous studies have shown that bats will actually dip down for a drink from smooth horizontal surfaces—whether they're water-filled or not. The study is in the journal Science.

格雷夫表示，这是因为自然界中存在大量的水平面，比如湖泊和池塘。即使湖泊会反射开蝙蝠的叫声，蝙蝠的进化程度也已经达到能够感知水平水面的回声了。事实上，之前的研究已经表明，蝙蝠还会啄一下光滑的水平表面——不管其是否是水面。这项研究发表在《科学》杂志上。

So what are conservationists to do? "Obviously we have to be realistic, right? We can't start making all our windows rough and textured⁹." But if we build near crucial bat habitats, we could install acoustic¹⁰ deterrents¹¹ to drive the flying mammals away from buildings. "And certainly you could start looking at architectural possibilities, if you don't make a smooth surface smooth all the way but make ridges¹² inside, like a mosaic¹³." And perhaps bat-friendly architecture would result in new designs…pleasing to human perception, too.

那么，自然资源保护主义者应该做些什么呢?“很明显，我们必须要实事求是，对吧?我们不可能要求所有的窗户都变成粗糙且有纹路的状态。”不过，我们可以在主要的蝙蝠栖息地做建设时，安装上声障来驱赶这些蝙蝠使其远离建筑物。“当然，我们也可以从建筑学上着手。比如建筑表面不做成全光滑的，而是像马赛克一样内部做出脊状形态。”也许“亲蝙蝠”设计会体现在新型建筑设计上……同时还满足人类的感知需求。