科学美国人60秒 SSS 社交关系对蝙蝠成功捕猎的重要性

This is Scientific American's 60-second Science, I'm Jason Goldman.

这里是科学美国人——60秒科学系列，我是杰森·古德曼。

Each night, small groups of a species called velvety¹ free-tailed bats emerge from their roosts in the Panamanian rain forests to hunt for their insect prey² using echolocation.

每天晚上，一小群天鹅绒无尾蝙蝠会从巴拿马雨林的栖息地出来，利用回声定位捕食昆虫。

"When bats are hunting, especially when they're in open areas, they produce two really distinct call types.

“蝙蝠在捕食时，尤其是在开阔地带捕食时，会发出两种截然不同的叫声。

So they have their 'search-phase' calls when they're just scanning the environment.

如果它们只是在扫描环境，它们会发出‘搜索阶段’的叫声。

And then they have 'feeding buzzes' when they actually detect prey, like an insect swarm³."

而当它们真的发现昆虫群等猎物时，就会发出‘进食吱吱声’。”

Jenna Kohles, a graduate student at the Max Planck Institute of Animal Behavior in Germany.

德国马克斯·普朗克动物行为研究所的研究生詹娜·科尔斯说到。

Both types of calls are typically too high-pitched for us to hear.

对我们来说，这两种叫声的音高通常太高，所以人耳听不到。

But other bats can eavesdrop⁴ on those feeding buzzes and use them as a cue for finding food.

但是其它蝙蝠可以偷听到这些“进食吱吱声”，并以此作为寻找食物的线索。

And it's always been assumed that the other calls, search-phase calls, don't include that kind of social information.

人们一直假设另一种叫声即“搜索阶段”叫声，不包括这种社交信息。

But Kohles and her team wondered if search-phase calls might also be social and help bats stick together in the dark.

但科尔及其团队想知道，“搜索阶段”叫声是否也具有社交性，是否能帮助蝙蝠在黑暗中团结在一起。

"This is why we then tested first whether these echolocation calls they produce when they're scanning the environment contain information about a bat's identity,

“所以我们后来先进行了测试，看看它们扫描环境时发出的回声定位叫声是否包含与蝙蝠身份有关的信息，

like in the form of an individual signature.

比如个体签名形式的身份信息。

And then, more importantly, we wanted to test whether bats can actually use this information to discriminate⁵ between different individuals, just using these search-phase echolocation calls."

更重要的是，我们想测试蝙蝠是否真能仅利用‘搜索阶段’回声定位叫声这种信息来来区分不同的个体。”

The researchers captured wild bats and exposed them to a particular call over and over again until they became bored and stopped reacting.

研究人员捕捉野生蝙蝠，让它们一遍又一遍地听一种特定叫声，直到它们感到厌烦并停止反应。

Then the researchers played the same type of call but recorded from a different bat.

之后研究人员播放另一种蝙蝠发出的同一种叫声。

If the bats reacted, it means that they noticed that the identity of the caller had changed.

如果这些蝙蝠有反应，就意味着它们注意到鸣叫者的身份发生了变化。

And that's exactly what happened, which suggests that some kind of individual signature is encoded within search-phase calls.

而这确实发生了，这表明，个体签名编入了“搜索阶段”叫声中。

The results are in the journal Behavioral Ecology.

这项研究结果发表在《行为生态学》期刊上。

Many other animals that hunt in groups use vocalizations to keep connected.

其他许多成群捕猎的动物都用回声定位来保持联系。

But bats already invest most of their vocal⁶ resources in echolocation for hunting.

但蝙蝠已将大部分声音资源投入捕猎回声定位中。

So it appears that these bats have figured out how to accomplish both tasks—hunting and coordination—using a single type of vocalization.

因此，这些蝙蝠似乎已找到完成狩猎和协调这两项任务的方式，那就是利用单独类型的回声定位。

"Bats can use this in a social strategy to forage⁷ within hearing distance of particular individuals to potentially find food faster or to find food more predictably."

“蝙蝠可以在社交策略中使用这种方法，在特定个体的听觉距离内觅食，以便更快地找到食物，或者更有预见性地找到食物。”

Kohles says that this finding offers a new way to think about the evolution of social communication in bats—

科尔斯表示，这一发现为思考蝙蝠社交沟通的进化提供了新方法，

and that we may be underestimating the role of relationships in bats' success at hunting.

我们可能低估了社交关系在蝙蝠成功捕猎中的作用。

Thanks for listening for Scientific American's 60-second Science. I'm Jason Goldman.

谢谢大家收听科学美国人——60秒科学。我是杰森·古德曼。

1 velvety   

adj. 像天鹅绒的, 轻软光滑的, 柔软的

参考例句：

• a velvety red wine 醇厚的红葡萄酒
• Her skin was admired for its velvety softness. 她的皮肤如天鹅绒般柔软，令人赞叹。

2 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

3 swarm   

n.(昆虫)等一大群；vi.成群飞舞；蜂拥而入

参考例句：

• There is a swarm of bees in the tree.这树上有一窝蜜蜂。
• A swarm of ants are moving busily.一群蚂蚁正在忙碌地搬家。

4 eavesdrop   

v.偷听，倾听

参考例句：

• He ensconced himself in the closet in order to eavesdrop.他藏在壁橱里，以便偷听。
• It is not polite to eavesdrop on the conversation of other people.偷听他人说话是很不礼貌的。

5 discriminate   

v.区别，辨别，区分；有区别地对待

参考例句：

• You must learn to discriminate between facts and opinions.你必须学会把事实和看法区分出来。
• They can discriminate hundreds of colours.他们能分辨上百种颜色。

6 vocal   

adj.直言不讳的；嗓音的；n.[pl.]声乐节目

参考例句：

• The tongue is a vocal organ.舌头是一个发音器官。
• Public opinion at last became vocal.终于舆论哗然。

7 forage   

n.(牛马的)饲料，粮草；v.搜寻，翻寻

参考例句：

• They were forced to forage for clothing and fuel.他们不得不去寻找衣服和燃料。
• Now the nutritive value of the forage is reduced.此时牧草的营养价值也下降了。