科学美国人60秒 当主人归家时 狗狗为啥会眼泪汪汪？（在线收听）

This is Scientific American’s 60-Second Science. I’m Karen Hopkin.

这里是科学美国人——60秒科学系列，我是凯伦·霍普金。

After an exhausting day at the office, it’s hard not to smile when you’re greeted by a delirious display of uncontrolled canine joy.

在办公室度过了疲惫的一天后，当你看到狗狗们疯狂地表现出无法控制的喜悦时，你很难不会微笑。

But it’s not just the happy yapping and wriggling tail wagging that tug at our heartstrings.

但牵动我们心弦的不仅仅是欢快的叫声和扭动的尾巴。

Because a new study shows that dogs’ eyes fill with tears when reunited with their people--an effect that evokes our nurturing instincts.

因为一项新的研究表明，当狗狗与它们的家人团聚时，它们的眼睛里会充满泪水--这种效果唤起了我们的养育本能。

The findings appear in the journal Current Biology.

这项研究结果发表在《当代生物学》杂志上。

Takefumi Kikusui became interested in doggies’ damp and adoring gazes while watching his pet poodle interact with her pups.

Takefumi Kikusui在观察宠物贵宾犬与它的小狗互动时，他对狗狗们眼泪汪汪和充满崇拜的眼神产生了兴趣。

When she was nursing her puppies, her face becomes so cute.

当贵宾犬给自己的小狗喂奶时，它的脸变得如此可爱。

Of course she’s so cute as always. But more.

当然，它一直都很可爱。但是比以往更可爱了。

At some point Kikusui, who’s a professor of veterinary medicine at Azabu University in Japan, realized that his adorable mama dog had tears in her eyes.

Kikusui是日本麻布大学的兽医教授，在某个时候，他意识到可爱的狗妈妈眼里含着泪水。

That potential connection between unbearable cuteness and unshed tears sent Kikusui scurrying away from his poodle and back to the lab.

招架不住的可爱与打转的眼泪之间的潜在联系让Kikusui匆匆离开他的贵宾犬，回到实验室。

In the test, we initially measure the baseline tear volumes when dogs were together with the owner in their house.

在测试中，我们首先测量了狗狗和主人在一起时的泪水基本量。

Then the owner would high-tail it off for five or six hours.

随后主人就会在五到六个小时后迅速离开小狗。

When the owner came back, we measure tear volume again.

当主人回来时，我们又测量了一次泪液量。

And found that the reunion with the owner stimulate tear secretion.

发现与主人团聚会刺激泪液分泌。

But it only worked with the dog’s owner.

但这只对狗狗的主人有效。

There was no increase in tears when the dogs were separated from the owner and reunited with the dogs’ caretaker in a dog care center.

当狗狗与主人分开，在看护中心与其看护人团聚时，它们的眼泪并没有增加。

The researchers suspected that the tearful reaction was stimulated by oxytocin--a hormone associated with social bonding.

研究人员怀疑，流泪的这种反应是由催产素刺激的，催产素是一种与社会联系有关的激素。

They had shown previously that oxytocin is boosted when dogs interact with their owners.

他们之前已经证明，当狗狗与主人互动时，催产素会增加。

And oxytocin receptors have been found to be abundant in the glands that secrete tears in mice.

人们已发现催产素受体在小鼠分泌泪液的腺体中含量丰富。

So we applied oxytocin to the dogs’ eyes.

所以我们把催产素涂在了小狗的眼睛上。

And voila…the dogs grew weepy.

瞧，这些狗狗们变得眼泪汪汪。

But to what end?

但这样的目的是什么呢?

In other words, is there some benefit to this lachrymose behavior?

换句话说，这种流泪的行为会有什么好处吗?

To find out, Kikusui and his colleagues showed volunteers a couple of hound head shots.

为了找到答案，Kikusui和他的同事们向志愿者们展示了一对猎犬的头部照片。

One was a normal dog face.

一张是正常的狗脸。

And the other was teary dog face in which we added artificial tears.

另一张是泪汪汪的狗脸，我们在狗脸上添加了人造眼泪。

The volunteers were more likely to want to cuddle and care for the mutts with big, wet puppy-dog eyes--

志愿者们更愿意拥抱和照顾那些眼睛大大的、眼泪汪汪的小狗--

--suggesting that teary eyes of dogs can facilitate the human caregiving behavior.

--这表明狗狗流泪的眼睛可以促进人类的照顾行为。

So dogs turn on the waterworks and their owners roll over.

所以当狗狗的眼睛开始流泪，它们的主人就会翻身照顾它们。

Now, that’s quite a clever trick!

此时，这是一个相当聪明的技巧!

For Scientific American’s 60-Second Science, I’m Karen Hopkin.

谢谢大家收听科学美国人——60秒科学。我是凯伦·霍普金。

Thank you for listening.

感谢收听。