科学美国人60秒：草原田鼠的一夫一妻制

Ashleigh Papp: This is Scientific American’s 60-Second Science, I'm Ashleigh Papp.

阿什利·帕普：这里是《科学美国人》的60 秒科学，我是阿什利·帕普。

Monogamy in animals…and let's be honest, in humans too…is a funny thing. Only a few animal species have been lumped into the one-partner-for-life category, and even then, there are exceptions to those rules.

动物的一夫一妻制......老实说，人类的一夫一妻制......也是一件有趣的事情。只有少数动物物种被归入终身伴侣的类别，即便如此，这些规则也有例外。

Prairie voles are furry little rodents that live throughout North America. They’re a particularly interesting species because they form lifelong partnerships. 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.

草原田鼠是一种毛茸茸的小型啮齿动物，生活在北美各地。它们是一个特别有趣的物种，因为它们形成了终生的伙伴关系。Annaliese Beery是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，他在野外和实验室研究田鼠的一夫一妻制。

Annaliese Beery: So I would define monogamy as a formation of a lasting partnership or a social relationship between mates. 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. Monogamy is fairly rare in rodents, and it's also unusual for rodents to form lasting social relationships of any kind.

Annaliese Beery：所以我将一夫一妻制定义为伴侣之间形成一种持久的伙伴关系或社会关系。社会关系对人类生物学非常重要，草原田鼠是实验室中研究的唯一具有这种特征的物种之一。在啮齿动物中，一夫一妻制是相当罕见的，而且啮齿动物形成任何形式的持久社会关系也很罕见。

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

帕普：我们已经知道支持草原一夫一妻制的一些事情——比如当配偶稀缺时，保持与你在一起的那个是有意义的，或者当两性都坚持抚养他们的孩子时。但到目前为止，对于动物为什么或如何只选择一个伴侣，还没有一个明确的解释。

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

不管是什么原因，保持一夫一妻制需要双方的努力。为了更好地理解终身关系是如何运作的，Beery 和她的团队想知道雄性和雌性草原田鼠是否在长期工作方面进行了同等投资。

To find out, the researchers set up an experiment with three phases. In the first phase, they had to teach the prairie voles how to open a door controlled by a lever.

为了找出答案，研究人员设置了一个分三个阶段的实验。在第一阶段，他们必须教草原田鼠如何打开由杠杆控制的门。

Beery: It was actually really hard to get prairie voles to press a lever for a reward. And we had some voles who never learned the task, and they were not included in the study. We had other voles who learned to press the lever in non-typical ways, one female liked to sit on the lever in order to activate it. 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.

Beery： 实际上，要让草原田鼠按下杠杆获得奖励是非常困难的。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。还有田鼠学会了以非典型的方式按杠杆，一只雌性田鼠喜欢坐在杠杆上，以启动它。然后有一天，什么东西突然灵光一照，她转过身来，开始用爪子按住它，用正确的方式得到了食物。

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

Papp：团队通过将杠杆按压与开门相关联来建立这项技能。

In phase two, there were two doors, controlled by two different levers. 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. (Just FYI, these rodents really aren't into swimming pools.)

在第二阶段，有两扇门，由两个不同的杠杆控制。一扇门通向一个舒适的窝，里面有木屑、新鲜农产品，甚至还有麦片，而另一扇门通向一个浅水池。(仅供参考，这些啮齿动物真的不喜欢游泳池。)

The voles could distinguish between two doors, two levers, and two different outcomes. And ultimately, both the males and females overwhelmingly pressed the lever that took them into the cushy chamber over the water torture.

田鼠可以区分两扇门、两根杠杆和两种不同的结果。最终，雄性和雌性都压倒性地按下了将他们带入舒适房间的杠杆，而不是泳池。

In phase 3, they took a quick break from the lever pressing and introduced each vole to a member of the opposite sex. The two voles got 48 hours to bond and grow fond…and then the lever pressing resumed.

在第 3 阶段，让田鼠在杠杆按压前中场休息，并将每只田鼠介绍给异性成员。两只田鼠有 48 小时的时间来培养感情……然后继续按下杠杆。

Each of the trained voles were given the option of two levers and two doors again. But this time, one of the doors led to their partner and the other led to a new member of the opposite sex.

每只训练有素的田鼠都可以再次选择两个杠杆和两个门。但这一次，一扇门通向他们的伴侣，另一扇通向一个新的异性成员。

After all of the little vole-sized levers were pulled, Beery and her team analyzed the results. They found that even when it comes to monogamous prairie voles…males and females sometimes have different priorities.

试验结束后，Beery 和她的团队分析了结果。他们发现，即使是一夫一妻制的草原田鼠……雄性和雌性有时也有不同的优先选择。

Beery: So females worked hardest to get to familiar male mates versus unfamiliar strangers. The males were interesting because they showed diverse behaviors, some of them acted like the females and worked hardest to get to their mates consistently over the course of the study. 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.

Beery： 雌性努力地去接触熟悉的雄性伴侣，而非破圣人。雄性则很有趣，因为它们表现出不同的行为，其中一些表现得像雌性，并且在研究过程中努力地始终如一地接近它们的伴侣。另外一些雄性一直在努力接触陌生的雌性，还有的雄性则处于中间状态，它们会在一天内更多地追求熟悉的雌性，而第二天又会追求不熟悉的雌性。

Papp: Their results were published in the journal Genes, Brain and Behavior. [Annaliese K. Beery, et al., Sex differences in the reward value of familiar mates in prairie voles]

Papp：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. In other experiments, vole researchers have observed "wandering," or a preference by males for the unfamiliar females. But many of those studies were performed out in the wild, and this research removed those external pressures. 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.

总的来说，这表明两性在社会动机方面存在很大差异。在之前的实验中，研究人员观察到田鼠的“游荡”行为，即雄性对不熟悉的雌性的偏爱。但其中许多研究都是在野外进行的，而这项研究消除了这些外部压力。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，好吧，也许它们喜欢这样。

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 Beery 的说法，测试田鼠一夫一妻制有助于我们更好地了解不同类型的人际关系，以及我们选择与谁共度时光的过程。

For prairie voles, the investment seems a bit skewed to the female side, but no need to throw shade on the males, Beery says, there's likely a legit explanation out there. And while science looks for that reason—maybe don't give up on finding your one true love quite yet.

Beery 说，对于草原田鼠来说，雌性似乎投入了更多的感情，但没有必要贬低雄性，总会有一个合理的解释。虽然科学正在寻找这个原因 - 也许是不要放弃寻找真爱。

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

以上是《科学美国人》的 60 秒科学，阿什利·帕普报道。