This is Scientific American's 60-second Science, I'm Ashleigh Papp.

这里是科学美国人——60秒科学系列，我是阿什利·帕普。

Monogamy in animals…and let's be honest, in humans too…is a funny thing.

动物的一夫一妻制，老实说，人类的一夫一妻制也很有趣。

Only a few animal species have been lumped into the one-partner-for-life category, and even then, there are exceptions to those rules.

只有少数动物物种被归为终身伴侣类别，即便如此，这些规则也有例外。

Prairie voles are furry little rodents that live throughout North America.

草原田鼠是一种毛茸茸的小型啮齿动物，生活在北美各地。

They’re a particularly interesting species because they form lifelong partnerships.

它们是一种特别有趣的物种，因为它们会形成终身伴侣关系。

Annaliese Beery, a behavioral neuroscientist with Smith College in Massachusetts and the University of California at Berkeley, studies vole monogamy in the wild and in the lab.

马萨诸塞州史密斯学院和加州大学伯克利分校的行为神经学家安娜莉丝·比里在野外和实验室中研究田鼠的一夫一妻制。

So I would define monogamy as a formation of a lasting partnership or a social relationship between mates.

所以我将一夫一妻制定义为一种持久的伴侣关系或配偶之间的社会关系。

Social relationships are very important for human biology and prairie voles are one of the only species that are studied in the lab that exhibit this trait.

社会关系对人类的生物学来说非常重要，而草原田鼠是实验室中仅有的表现出这一特征的物种之一。

Monogamy is fairly rare in rodents, and it's also unusual for rodents to form lasting social relationships of any kind.

一夫一妻制在啮齿动物中是相当罕见的，而且啮齿动物也不太可能形成任何形式的持久社会关系。

We already know about some things that support monogamy in the wild—like when mates are scarce and it makes sense to hold onto the one you're with, or when both sexes stick around to raise their young.

我们已经了解到支持野外一夫一妻制的一些事情，比如当配偶稀少时，抓住和你在一起的配偶是有意义的，或者当两性都坚持抚养他们的孩子时，这样做也是有意义的。

But so far, there isn't one clear explanation as to why or how animals opt for only one partner.

但到目前为止，对于动物为什么或怎么只选择一个伴侣，还没有一个明确的解释。

Whatever the reasons, staying monogamous requires effort from both sides.

不管是什么原因，保持一夫一妻制需要双方的努力。

To better understand how lifelong bonding works, Beery and her team wanted to know if both male and female prairie voles make equal investments in making the long haul work.

为了更好地理解终生的感情纽带是如何起作用的，比里和她的团队想要知道，雄性和雌性草原田鼠在维持长期的感情关系方面是否都有同等的投入。

To find out, the researchers set up an experiment with three phases.

为了找到答案，研究人员设置了一个分为三个阶段的实验。

In the first phase, they had to teach the prairie voles how to open a door controlled by a lever.

在第一阶段，他们必须教草原田鼠如何打开一扇由杠杆控制的门。

It was actually really hard to get prairie voles to press a lever for a reward.

实际上，要让草原田鼠按下杠杆获得奖励是非常困难的。

And we had some voles who never learned the task, and they were not included in the study.

我们有一些田鼠从来没有学会过这项任务，它们没有被包括在这项研究中。

We had other voles who learned to press the lever in non-typical ways.

其他田鼠学会了以非典型的方式按杠杆，

One female liked to sit on the lever in order to activate it.

一只雌性田鼠喜欢坐在杠杆上，以启动它。

And then one day, something clicked and she turned around and started pressing it with her paw and getting the food pellet in the ordinary way.

然后有一天，有个东西咔哒一声响了起来，她转过身来，开始用爪子按它，然后就像平常一样得到了食物团子。

The team built on that skill by associating the lever pressing with a door opening.

该团队通过将按压杠杆与打开门联系起来建立了这项技能。

In phase two, there were two doors, controlled by two different levers.

在第二阶段，有由两个不同的杠杆控制的两扇门。

One of the doors led to a cushy rodent pad complete with wood shavings, fresh produce and even Cheerios, while the other led to a shallow pool of water.

其中一扇门通向一个舒适的啮齿类动物垫子，上面有木屑、新鲜农产品，甚至还有脆谷乐，而另一扇门通向一个浅水池。

The voles could distinguish between two doors, two levers, and two different outcomes.

田鼠能够区分两扇门、两根杠杆和两种不同的结果。

And ultimately, both the males and females overwhelmingly pressed the lever that took them into the cushy chamber over the water torture.

最终，雄性和雌性都以压倒性的优势按下了把它们带进舒适房间的杠杆，而让它们受到落水折磨的房间。

In phase 3, they took a quick break from the lever pressing and introduced each vole to a member of the opposite sex.

在第三阶段，他们在按压杠杆的过程中稍事休息，然后将每只田鼠介绍给异性田鼠。

The two voles got 48 hours to bond and grow fond…and then the lever pressing resumed.

两只田鼠有48小时的时间来培养感情，然后继续按杠杆。

Each of the trained voles were given the option of two levers and two doors again.

每只经过训练的田鼠又有两根杠杆和两扇门可供选择。

But this time, one of the doors led to their partner and the other led to a new member of the opposite sex.

但这一次，一扇门通向他们的伴侣，另一扇门通向一个新的异性伴侣。

After all of the little vole-sized levers were pulled, Beery and her team analyzed the results.

在拉动所有田鼠大小的小杠杆后，比里和她的团队分析了结果。

They found that even when it comes to monogamous prairie voles…males and females sometimes have different priorities.

他们发现，即使是在一夫一妻制的草原田鼠身上，雄性和雌性有时也有不同的优先选择。

So females worked hardest to get to familiar male mates versus unfamiliar strangers.

与不熟悉的陌生配偶相比，雌性田鼠更努力地寻找熟悉的雄性配偶。

The males were interesting because they showed diverse behaviors.

这些雄性田鼠很有趣，因为它们表现出不同的行为。

Some of them acted like the females and worked hardest to get to their mates consistently over the course of the study.

在研究过程中，其中一些表现得像雌性田鼠，它们一直在努力接近它们的配偶。

Other males consistently worked hardest to get to unfamiliar females, and yet other males were sort of intermediate where they would press more for a familiar female on one day and an unfamiliar female on the next day.

其他的雄性田鼠会一直努力去接近陌生的雌性田鼠，而其他的雄性田鼠则处于中间状态，它们会在第一天为熟悉的雌性按很多下，第二天为陌生的雌性按很多下。

Their results were published in the journal Genes, Brain and Behavior.

他们的研究结果发表在《基因、大脑和行为》杂志上。

Overall, this points to a big difference between the sexes when it comes to social motivation.

总的来说，这表明两性在社交动机方面存在巨大差异。

In other experiments, vole researchers have observed "wandering," or a preference by males for the unfamiliar females.

在其他的实验中，田鼠研究人员观察到“偏离”，即雄性田鼠对不熟悉的雌性田鼠的偏爱。

But many of those studies were performed out in the wild, and this research removed those external pressures.

但许多研究是在野外进行的，这项研究消除了这些外部压力。

That seems to mean that some of these little males were sometimes flighty about staying true to their mate because, well, maybe they felt like it.

这似乎意味着，这些小雄性田鼠有时会朝三暮四，缺乏对伴侣的忠诚，因为也许它们想要这样。

According to Beery, putting vole monogamy to the test helps us better understand the different types of human relationships and our process for selecting who we spend time with.

根据比里的说法，测试田鼠的一夫一妻制有助于我们更好地理解不同类型的人际关系，以及我们选择相处对象的过程。

For prairie voles, the investment seems a bit skewed to the female side, but no need to throw shade on the males.

对草原田鼠来说，雌性似乎投入了更多的感情，但没有必要贬低雄性。

Beery says, there's likely a legit explanation out there.

比里说，可能存在一个合理的解释。

And while science looks for that reason—maybe don't give up on finding your one true love quite yet.

虽然科学在寻找这个原因，但也许还不能放弃寻找真爱。

For Scientific American's 60-Second Science, I’m Ashleigh Papp.

感谢大家收听科学美国人——60秒科学。我是阿什利·帕普。

来源：Scientific American