猴子的近亲会发出类似的叫声

In the wild,monkeys need to keep their eyes peeled for all sorts of dangers, like leopards and eagles and snakes.

在野外，猴子需要密切留意各种危险，比如豹子、老鹰和蛇。

But the green monkeys studied by Julia Fischer of the German Primate Center have an additional challenge: they also have to scan the skies for drones.

但德国灵长类动物研究中心的朱莉费舍尔研究的绿猴还面临另一项挑战:它们还必须观察天空，注意无人机。

"Why did we fly a drone over green monkeys,one may ask." One may indeed. The answer is that Fischer and her colleagues are interested in how primates communicate.

“有人可能会问，为什么要让无人机在绿猴头顶上空飞?”可能的确有人问。答案是费舍尔和同事对灵长类动物的交流方式很感兴趣。

In a classic study back in the 1980s, scientists showed that East African vervet monkeys produce alarm calls that are specifc for the predators they encounter.

在上世纪80年代的一项经典研究中，科学家发现，东非长尾黑颚猴在遇到捕食者时会发出特定的警报叫声。

So for example, vervet monkeys hearing a leopard alarm might scurry up a tree, whereas the eagle call sends them running for cover under the closest shrub. 

例如，长尾黑颚猴听到豹子警报声时可能会迅速爬上树，而在听到老鹰警报声时会跑到最近的灌木丛中藏起来。

Now, the green monkeys that live in Senegal share a similar system to warn of leopards and snakes. But they aren't known to raise a ruckus in response to birds of prey.

现在，生活在塞内加尔的绿猴会用类似的系统来警报遇到豹子和蛇的情况。但人们不知道它们对猛禽的反应会引起骚乱。

"And so therefore we decided to fly a drone over them." The researchers treated 80 green monkeys to a show of drones.

“因此我们决定让无人机从它们的头顶上空飞过。”研究人员让80只绿猴观看无人机表演。

How did the animals react to this unfamiliar aerial intruder? "The monkeys did respond.They responded with alarm calls, and they responded by running away."

它们对这个不熟悉的空中入侵者有何反应?“猴子们确实做出了反应。它们发出了警报声，而且逃走了。”

Here's where things get really interesting: the calls the green monkeys made after spotting the drones were different from the ones theyuse to signal leopards or snakes.

有趣的是:绿猴发现无人机后发出的叫声，与它们用来警报遇到豹子或蛇时发出的声音不同。

But even more intriguing: "And when we did anacoustic analysis, these alarm calls were almost eerily similar to the ones of the east African vervets.'

但更有趣的是:“我们进行声学分析后发现，这些警报叫声与东非长尾黑颚猴的警报声惊人地相似。”

The findings are described in the journal Nature Ecology & Evolution. The fact that the two monkey species seem to speak the same language, if you will, even though they diverged from their last common ancestor some 3 million years ago,

研究结果发表在《自然生态与进化》期刊上。事实.上，如果你允许我这么说的话，即使这两种猴子在300万年前就从它们最后一个共同祖先处分离出来，但它们似乎说着同样的语言，

suggests that this vocal warning system is hardwired. So if you hear a monkey go, watch out for a hungry bird. Or check to see if you got a package delivered.

这表明这种声音警报系统是固有的。因此，如果你听到猴子发出这样的叫声，要小心饥饿的鸟。或者检查一下是不是包裹到了。