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Sometimes a snout full of snot can be just what the doctor ordered. At least if you’re a dolphin. Because a new study shows that a little bit of mucus helps these marine¹ mammals generate the rapid-fire stream of clicks they emit and use for echolocation.

医生叮嘱，至少如果你是只海豚，鼻子里要充满鼻涕。因为一项新的研究表明，一点粘液可以帮助这些海洋哺乳动物产生急速连续的咔哒声并利用回声进行定位。

First off, let’s just get this out of the way. Dolphins do not actually sound like this. [Flipper² laugh sound] That’s a made-for-TV giggle³ that some say is actually the doctored call of a bird: the Australian kookaburra.

首先声明，海豚实际上并不能发出这样的声音。那种咯咯的笑声出自一部电视电影，有人说实际上是用鸟叫声来伪造的——澳大利亚笑翠鸟。

Real dolphins, like these bottlenoses, sound more like this. [Bottlenose sounds] They use their clicks, chirps⁴ and whistles to navigate⁵, communicate and to catch their next meal. The high-frequency clicks, in particular, help Flipper and his kind locate and track fish dinners.

真正的海豚，像这些宽吻海豚，听起来更像这样。它们通过发出的咔哒声、啾啾声、口哨声来进行导航、通讯和捕食。尤其是高频的咔哒声，可以帮助Flipper和它的同类进行定位，追踪晚餐。

Dolphins make these sounds by forcing air through a nasal passage just beneath the blowhole. In this nasal region are liplike flaps of tissue called dorsal⁶ bursae that vibrate and collide to produce dolphin talk.

海豚们迫使空气通过通气孔下方的鼻道，从而发出这种声音。鼻区有唇形片状瓣膜，被称为背黏液囊，通过振动和碰撞使海豚能够“讲话”。

Now, a team of researchers has created a simplified model that can reproduce this characteristic dolphin chatter⁷. And they found that the secret ingredient is snot.

现在，一组研究人员已经建立了一个简化的模型，可以重现海豚语这一特征。并且他们发现的秘密成分是鼻涕。

While looking through the literature, oceanographer Aaron Thode stumbled across a model that represented vocal⁸ cords as masses connected by springs—which store and release energy—and dampers, which dissipate that energy. This model successfully replicated⁹ the essential characteristics of the system, like the frequency of vocal cord vibration¹⁰.

在看文献时，海洋学家Aaron Thode偶然发现了一个模型：将声带看作由弹簧相连的集块——储藏和释放能量以及消散能量的阻尼器。这个模型很好地契合了发声系统的基本特征，如声带振动的频率。

So Thode enlisted¹¹ his father Lester, a retired¹² nuclear physicist¹³ from Los Alamos National Lab, to help him fit the model to a dolphin’s nasal anatomy¹⁴. When the Thodes compared the simulated sounds produced by their model to a recording¹⁵ of actual dolphins, they found that the model mimicked¹⁶ both the loud thump¹⁷ and extended ring that are part of the natural click.

因此，Thode让他的父亲加入其中，帮助他使这个模型与海豚的鼻部解剖相符合。他的父亲是洛斯阿拉莫斯国家实验室退休的核物理学家。当他们将模型产生的模拟声音与海豚真实录音进行比较时，他们发现，模型模拟的撞击声和回声，是海豚原咔哒声的一部分。

The initial thud comes from when those dorsal bursae collide. And the reverberation¹⁸ results from the vibrations¹⁹ that linger when the tissues pull apart. But Thode the younger says the bursae have to be somewhat sticky for the clapping together and snapping apart to produce a noise with the correct loudness and pitch. That stickiness comes courtesy of the mucus. Thode vocalized the results at the meeting of the Acoustical²⁰ Society in Salt Lake City.

最初的声音来自背部黏液囊的碰撞。而持续的混响来源于组织分离时产生的振动。不过 Thode认为，黏液囊必须要有足够的粘性，一下靠拢又分开，才能产生这种声音并达到正确的音量和音高。这种粘性来自粘液，Thode在盐湖城的声学学会上发布了该研究成果。

The match between the simulated sounds and the real deal is encouraging, and the Thodes plan to keep up their collaboration²¹ to refine their model. “Yeah, I guess some fathers and sons bond over football, but my dad and I, I guess we bonded²² over differential equations and writing this paper.”

模拟声与海豚原声的匹配度激励着人们，Thodes打算继续协作，完善他们的模型。“是的，我认为某些父子的亲情因为足球而更加深厚，而我和我父亲，我想是因为微分方程和撰写这篇论文。”