科学美国人60秒：大象怎么像老鼠一样吱吱叫?

Karen Hopkin: This is Scientific American’s 60-Second Science. I’m Karen Hopkin.
凯伦Hopkin：这是《科学美国人》的 60 秒科学。我是Karen Hopkin。

Ask anyone what an elephant sounds like, and they’ll come up with something like this:
问到大象的声音是什么样的，大家可能会想到这样的声音：

But some elephants can also do this:
但有些大象也可以这样叫：

And researchers using an acoustic camera that converts sounds into colors have figured out how. The findings appear in the journal BMC Biology. [Veronika C. Beeck et al., A novel theory of Asian elephant high-frequency squeak production.]
研究人员使用声学相机将声音转换为颜色，找到了大象吱吱叫的奥秘。研究结果发表在BMC 生物学杂志上。[Veronika C. Beeck 等人， 亚洲象高频吱吱声产生的新理论。]

Elephants actually have a few ways they can get their message across. In addition to the traditional trumpet...,
大象实际上有几种方法可以传达他们的信息，除了传统的小号声。

... they also communicate using a rumble whose pitch is often too low for humans to hear.
...他们还使用隆隆声进行交流，其音调通常低到人类无法听到。

Veronika Beeck: But then the Asian elephant, and the Asian elephant only, produces ridiculously high-pitched squeaks ...
Veronika C. Beeck：但是亚洲象，且只有亚洲象，会发出可笑的高亢吱吱声……

... that seem to come rather from a mouse than from an animal the size of an elephant.
......这种声音听起来更像是来自老鼠，而不是大象那种庞然大物。

Hopkin: Veronika Beeck of the University of Vienna. She and her colleagues set out to locate the source of these unusual chirps.
Hopkin： 维也纳大学的Veronika Beeck和她的同事着手寻找这些不寻常的吱吱声的来源。

Beeck: The only idea that was out there so far was that elephants produce squeaks in the same way as they produce the trumpets ...
Beeck：当时唯一的想法是，大象产生吱吱声的方式与产生小号声的方式相同。

Hopkin: That is, using their trunk.
Hopkin：也就是说，使用象鼻发声。

Beeck: So we started out with just observing the facial movements and posture of Asian elephants when they squeak.
Beeck：所以我们从观察亚洲象发出吱吱声时的面部动作和姿势开始。

Hopkin: First up: a group of 14 adult females at an elephant camp in Nepal.
Hopkin：在尼泊尔的一个大象基地，研究人员对14只成年雌象开展了初次研究。

Beeck: So first we observed that elephants squeak when they are aroused.
Beeck：我们首先观察到的是，大象受到刺激唤醒时就会发出吱吱声。

Hopkin: So any time they get excited—or upset.
Hopkin：所以每当他们兴奋或沮丧时。

Beeck: And they are easily upset—when there’s any strange noise or strange smells, a car passing by in the distance, a dog or a cow coming too close to the enclosure.
Beeck：而且它们其实很容易感到不安——比如有任何奇怪的噪音或气味，有汽车从远处经过，以及有只狗或牛离围栏太近时。

Hopkin: They also squeak in social situations.
Hopkin：他们在社交场合也会发出吱吱声。

Beeck: When they have only been separated briefly, and they greet each other again, they burst into exuberant choruses of trumpeting, rumbling and squeaking ...
Beeck：当他们只是短暂地分开，又再次互相打招呼时，它们会开始小号声、隆隆声和吱吱声的激情大合奏。

Hopkin: And even when having a bath.
Hopkin：甚至在洗澡的时候。

But are the squeaks coming from the trunk or the mouth?
但是，吱吱声到底是来自躯干还是嘴巴?

Beeck: That is where we used the acoustic camera. With an array of 48 microphones, the acoustic camera can calculate the time differences with which the sound reaches the different microphones and translate it into beautiful rainbow colors—which, in the end, makes you see rainbow colors coming out of the elephant’s mouth or trunk.
Beeck：这时候声学相机就派上用场了。这款声学相机含有一个由48个麦克风组成的阵列，可以计算出声音到达不同麦克风的时间差，并将其转变为美丽的彩虹色——最终，你会看到彩虹色信号的音源究竟是大象的嘴巴还是鼻子。

Hopkin: And what they found?
Hopkin：他们发现了什么?

Beeck: The rainbow colors clearly came out of the mouth when the elephant squeaked and out of the trunk when it did the trumpet.
Beeck：大象吱吱叫的时候，彩虹色是从大象的嘴里冒出来的，而大象‘吹小号’的时候，彩虹色是从大象的鼻子里冒出来的。

Hopkin: One particularly talented pachyderm, a female called Pawan, could squeak and snort at the same time.
Hopkin：有一只叫帕万（Pawan）的雌象特别有天赋，她可以同时发出吱吱声和哼哼声。

Beeck: And this told us that, clearly, the sound production mechanism has to be within the mouth. Because otherwise it wouldn’t be possible to produce a perfectly fine squeak and a perfectly fine nasal snort at the same time.
Beeck：这就告诉我们，吱吱声必须从口腔中产生，否则不可能同时发出完美的吱吱声和哼哼声。

Hopkin: The squeak, it appears, is made when an elephant presses air out between its tensed lips, which produces a noisy vibration.
Hopkin：吱吱声，似乎是由大象从紧闭的嘴唇之间挤出空气时发出的，这一过程会产生嘈杂的振动。

Beeck: I couldn’t find this technique to be described in any other animal except for human trumpet players. They call this technique lip buzzing.
Beeck：这种发声技术在任何其他动物身上都没被发现过，除了人类小号手。他们把这种技术称为嘴唇振动。

Hopkin: Beeck got pretty good at it.
Hopkin：贝克已经成了这方面的专家。

Beeck: Although I have to admit that it was not that easy to learn, which caused lots of skeptical and annoyed looks on the Metro on my daily commute.
Beeck：我得承认这招没那么容易学会，每天上下班在地铁上练习时，好多人用那种迷惑又恼火的眼神看着我。

Hopkin: Not all elephants make use of this buzz.
Hopkin：并非所有的大象都会发出吱吱声。

Beeck: In the first study group, only four of 14 elephants squeaked, and the ones that did did so a lot.
Beeck：在参与初次研究的14头大象中，只有4头发出过吱吱声，而且它们经常会这样吱吱。

Hopkin: Pawan would start practicing her signature sounds at four in the morning ...
Hopkin：帕万会在凌晨四点开始练习她的标志性声音……

Hopkin: Which generally got her the attention she was seeking, because ...
Hopkin：这通常会引起她所寻求的关注，因为……

Beeck: It’s extremely annoying.
Beeck：这种声音太烦人了。

Hopkin: Studying additional elephants that lived in family groups, the researchers found that when mama is a squeaker, the kids are, too.
Hopkin：随后对大象家庭进行研究时，研究人员发现如果象妈妈会吱吱叫，她的孩子们也会。

Beeck: And that is what made me think that maybe elephants actually have to learn how to squeak or when to squeak from the mother ...
Beeck：这让我想到，也许大象得从妈妈那儿学习如何或何时吱吱叫。

Hopkin: Which means that elephants may have something to teach us about the development of human language—and that parents really need to watch their mouths when they’re around little ones with big ears.
Hopkin：这意味着，我们或许能从大象身上学到人类语言发展的相关信息——在耳朵尖的小朋友身边时，家长们得多多注意言辞。

For Scientific American’s 60-Second Science, I’m Karen Hopkin.
这里是《科学美国人》的 60 秒科学，Karen Hopkin为您报道。