Monogamy-the practice of mating with a single individual for an extended period of time isn't that popular in the animal kingdom.Only about 3% of mammals are monogamous,and,although 95% of birds pair off (at least for one breeding season),paternity tests have revealed that the avian world is chock-full of cheaters.
一夫一妻制 在一段时间内只与一个配偶交配，在动物王国内并不流行。只有3%的哺乳动物施行一夫一妻制，同时 尽管95%的鸟类在至少一个繁殖季内成对出现，亲权鉴定实验显示 鸟类世界里尽是偷吃者.
The least loyal bird species might be the superb fairywren: they form lifelong bonds and,if you watched a pair of them from morning til night for an entire breeding season,you'd think they were perfectly faithful.But that's only because female fairywrens cheat under cover of darkness.
最不忠诚鸟要数壮丽细尾鹩莺 它们结伴终生，并且 如果你在整个繁殖季的白天内观察一对鹩莺，可能会觉得 它们挺忠诚的.但这只是因为鹩莺在夜幕的遮掩下偷情。
Using radio transmitters to track their movements,Researchers discovered that fertile females make daily,pre-dawn flights to other territories.These trips only last about 15 minutes,but apparently that's more than long enough.DNA tests show that just 25% of baby superb fairywrens are their father's biological offspring.
通过无线电发射器追踪其行踪，研究者发现 有生育能力的雌性每天黄昏前都会飞到其他地方。时间只有15分钟 不过显然够长了，DNA测试显示 只有25%的壮丽细尾鹩莺是其父亲真正的后代。
Even though modern genetics might be deflating our romantic notions about lovebirds,from a biological standpoint,pairing up with one individual and then copulating with others on the side makes a lot more sense than absolute sexual loyalty.
For birds,pairing up is a good strategy because their young require a ton of care,so males increase their chances of successful reproduction if they stick around and lend a beak.On the other hand,putting all of one's eggs in a single basket is a risky proposition,so it also makes sense for males to try and slip some of their genetic material into a few other nests if they can.
对鸟类而言 结对很有意义 因为幼鸟需要极多的关照，如果雄性绕在周围帮帮忙的话 繁衍的成功率更大。另一方面 把蛋都放在一个篮子里很危险，因此雄性在可能的情况下把基因散播到其他巢内，也有它的道理，
Females,of course,can't have more than one nest,but they can sneak around with other guys so their eggs have some varieties,Cheating might also help explain the otherwise unexpected physical differences between males and females in apparently monogamous species.We've long had a solid explanation for this kind of male/female dimorphism in explicitly non-monogamous species:because if a male plans to mate with many females,he needs to win their affection and fend off other suitors.
当然雌性只能抱一个窝，但它们可以和其他雄性私交 让蛋有些多样性。偷吃可能也可以解释貌似一夫一妻制物种间，后代与父母间的令人意外的外表差异，我们早就对这种全无一夫一妻制的物种间“夫妻”二者，有了令人信服的解释。因为 如果雄性打算与其他多个雌性结对，它就得赢得雌性欢心 同时提防其他适合对象。
Over thousands of generations,the traits that help him successfully mate can become more and more pronounced,even if they serve absolutely no other purpose.For example male gorillas who fight each other for exclusive mating rights with the females in their clan are much larger than female gorillas,while male and female gibbons,which are monogamous,are the same size.
千世万代后 助其成功结对的特性，会越来越显著 即使它们没有其他任何用处，比如 为了获得领地内与雌性猩猩独一交配权而与他者，大打出手的猩猩比雌性大得多，而一夫一妻制的雌性长臂猿大小相近.
Which brings us to our favorite primates,homo sapiens,There are undeniable physical differences between males and females,but it's unclear whether they're pronounced enough to suggest that our ancestors lived in harems like gorillas or whether our differences just stem from a monogamous but adulterous society like the superb fairywren's.
现在该说说我们的最爱 晚期智人了。他们雌雄性间的差异不可忽视，但还不清楚这是否足以证明，我们的祖先和猩猩一样 后宫三千 抑或是我们的跟植于，鹩莺般一夫一妻但偷情成性的社会里。
But one thing is clear:among all the species on Earth,monogamy is rare,and monogamy without cheating is rarer.There is,however,at least one known example of perfect,lifelong fidelity,and its name is Diplozoon paradoxum,When two of these young flatworms find each other,they literally fuse together to form what looks like a single organism,and this adultery-free union lasts for their entire long and amorous lives.
但有一点很清楚 地球上所有的生物中，一夫一妻极为少见 不偷吃的一夫一妻更罕见。不过 至少还有一个赤胆忠心的例子，它叫奇异双身吸虫。当两只年轻的吸虫相遇时，它们可说是融合在一起 形成貌似单一的有机体，这种忠贞的感情在它们漫长的一生内丝毫不变。
Which they spend sucking blood from fishgills.A truly romantic attachment!