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種危險，比如豹子、老鷹和蛇。
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.
但德國靈長類動物研究中心的朱莉費舍爾研究的綠猴還面臨另一項挑戰:它們還必須觀察天空，注意無人機。
"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.
“有人可能會問，為什麼要讓無人機在綠猴頭頂上空飛?”可能的確有人問。答案是費舍爾和同事對靈長類動物的交流方式很感興趣。
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.
在上世紀80年代的一項經典研究中，科學家發現，東非長尾黑顎猴在遇到捕食者時會發出特定的警報叫聲。
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，長尾黑顎猴聽到豹子警報聲時可能會迅速爬上樹，而在聽到老鷹警報聲時會跑到最近的灌木叢中藏起來。
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.
現在，生活在塞內加爾的綠猴會用類似的系統來警報遇到豹子和蛇的情況。但人們不知道它們對猛禽的反應會引起騷亂。
"And so therefore we decided to fly a drone over them." The researchers treated 80 green monkeys to a show of drones.
“因此我們決定讓無人機從它們的頭頂上空飛過。”研究人員讓80只綠猴觀看無人機表演。
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."
它們對這個不熟悉的空中入侵者有何反應?“猴子們確實做出了反應。它們發出了警報聲，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:綠猴發現無人機後發出的叫聲，與它們用來警報遇到豹子或蛇時發出的聲音不同。
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:“我們進行聲學分析後發現，這些警報叫聲與東非長尾黑顎猴的警報聲驚人地相似。”
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,
研究結果發表在《自然生態與進化》期刊上。事實.上，如果你允許我這麼說的話，即使這兩種猴子在300萬年前就從它們最後一個共同祖先處分離出來，但它們似乎說著同樣的語言，
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.
這表明這種聲音警報系統是固有的。因此，如果你聽到猴子發出這樣的叫聲，要小心飢餓的鳥。或者檢查一下是不是包裹到了。
閱讀更多 思否20191212 的文章
