经济学人321:爬行动物的排尿 可算是方便了

 　　Science and technology

　　科学技术

　　Reptilian¹ micturition

　　爬行动物的排尿

　　That's a relief

　　可算是方便了

　　Softshell turtles urinate through their mouths

　　鳖类通过其嘴部小便

　　WHY did the turtle stick its head in a bucket?

　　为什么乌龟会把它的脑袋扎到桶里呢？

　　sounds like the sort of riddle² asked by ten-year-olds in school playgrounds.

　　这听起来像十岁小孩子在学校操场上问的那种谜题。

　　But it was also asked recently by Yuen Ip of the National University of Singapore.

　　但是新加坡国立大学的元艾坡最近也问了这个问题。

　　And his answer, it has to be said, is precisely³ the sort that would appeal to a ten-year-old.

　　不得不说，他的答案恰恰是能吸引十岁小孩子的那种。

　　It is that turtles pee through their mouths.

　　答案是乌龟在用嘴巴撒尿。

　　The turtles in question are a species known as the Chinese softshell.

　　问题中的乌龟是一种被称为中华鳖的龟种。

　　By preference, they live in brackish⁴ swamps.

　　它们偏爱生活在微咸水湿地中。

　　But such swamps are liable to dry up, and then the turtles often do something which has puzzled zoologists⁵ for centuries:

　　但是这类湿地容易干涸，然后中华鳖经常会做出下面的动作，这让动物学家们困惑了几个世纪：

　　they put their heads into those small pools of water which remain and hold them there for as long as two hours.

　　鳖将它们的头部扎入余留的小水坑里，一待就是2个钟头。

　　In 1886 a pair of American biologists called Gage⁶, who were investigating this curious behaviour, dissected⁷ several turtles and found something strange in the animals' mouths, namely a set of structures that look like gills.

　　1886年，两名叫盖奇的美国生物学家研究了这一古怪的行为。他们解剖了数只鳖，在鳖的嘴巴里发现了些奇异之处，即一付长得像腮的结构。

　　That, they felt, explained how turtles were able to perform their head-in-a-pool trick, but not why. Softshells are not compelled to breathe through their gills; they have a perfectly⁸ adequate pair of lungs to do the job.

　　他们觉得这解释了鳖为何能做出把头扎入水坑的把戏，但无法解释为什么要这么做。鳖类并非必须要通过腮来呼吸，用它们的两个肺就完全足够了。

　　Nor did zoologists take seriously the hypothesis that the reptiles⁹ were pining for their aquatic¹⁰ homes and putting their heads in puddles¹¹ to keep their spirits up.

　　还有一个动物学家不会当真的假设：这些爬行动物离不开它们的水之家，它们将头伸入水坑里是为了提提神。

　　So, with the aid of a dozen turtles purchased from a local market, Dr Ip decided¹² he would try to solve the mystery once and for all.

　　所以艾坡博士从本地市场中买了十二只鳖，决定借助它们设法彻底的解开这个迷。

　　To do so, he strapped¹³ the animals down, to stop them moving, and provided each with a container of water into which it could dip its head if it chose.

　　他将这些鳖绑住，使它们无法移动，每一只前面都放了一个装有水的容器，以便鳖可以将头扎进去。

　　He also fitted each turtle with a plastic box that collected its urine, for he had a suspicion that therein lay the key to the mystery.

　　他还给每只鳖配了一个塑料桶来收集它们的尿液，他怀疑解开这个谜的钥匙就藏于其中。

　　This done, he monitored the animals for six days, paying particular attention to the chemistry of the water in the container.

　　准备好后，他对这些鳖监测了六天，并特别关注了容器中水的化学成分。

　　As expected, the turtles periodically submerged their heads in the water for between 20 and 100 minutes at a time.

　　正如所料，这些鳖定期将它们的头扎入水中，每次的时长在20到100分钟之间。

　　During these periods, Dr Ip noted¹⁴ that oxygen was being extracted from it.

　　在此期间，艾坡博士注意到水中的氧气在被提取。

　　This confirmed that turtles can, indeed, breathe underwater through their mouths.

　　这肯定了鳖确实可以在水下通过嘴部呼吸。

　　As the oxygen level fell, though, something else rose: the level of urea.

　　可是，随着氧含量下降，其他物质的含量上升了-尿素。

　　Clearly, the animals were disposing of this waste product by secreting¹⁵ it from their mouths into the water.

　　显然，鳖通过它们的嘴部悄悄的将这种废物排入了水中。

　　Indeed, a calculation Dr Ip performed, based on the volume and composition of the urine he collected in the plastic buckets, and of the head-dunking water at the end of each day, suggested that only 6% of the urea excreted by the turtles was leaving them in the traditional manner, via urine. The question was, why?

　　的确如此，艾坡博士根据每天结束后其在塑料桶中所收集尿液以及头部所扎入水的成分和体积进行了计算，表明鳖排泄的尿素中只有6%是以尿液这一传统方式排出的。问题是，为什么？

　　The most likely answer, as he explains in a paper in the Journal of Experimental Biology, is that urine, though cheap to produce when water is plentiful¹⁶, is a physiologically¹⁷ costly¹⁸ product when water is scarce.

　　最可能的答案是，正如他在《实验生物学》上发表的论文中解释的：虽然在水量丰沛时，产生尿液很便宜，但当水稀缺之时，这就成了一种生理上很昂贵的产品了。

　　Turtle kidneys have difficulty processing salt water, so for an animal that lives in a brackish environment potable water is always scarce.

　　鳖的肾无法处理咸水，所以对于一个生活在微咸水环境中的动物来说，食水一直弥足珍贵。

　　One way round this for a swimming animal is to develop an outlet¹⁹ which allows urea to dissolve directly in the water as it swims, which is what the turtles seem to have done.

　　对游泳动物来讲，规避此点的一种方式是进化出一个可以在其游水时将尿素直接排到水中排泄器官，就像鳖类似乎已经做到的那样。

　　Dr Ip looked at which genes²⁰ were active in the gill-like structures of the mouth and found one that appears, from its similarity to genes of known function from other species, to encode a urea transporter.

　　艾坡博士检查了嘴部这一类腮结构中有哪些基因在起作用，他发现一个基因，根据其和其他物种中已知功能基因的相似程度，会转译出一种尿素通道蛋白。

　　The turtle's gills, then, not only take in oxygen, they also excrete urea.

　　这样，鳖的腮不仅能吸取氧气，也能排出尿素。

　　If there is insufficient²¹ water to swim in, however, the turtles have to resort to desperate measures. The reason they stick their heads in puddles is in order to relieve themselves.

　　然而如果水量不足以供鳖游水时，它们会采取极端手段-将头扎入水坑是为了方便一下。

　　1.appeal to 呼吁,要求

　　To succeed, it must appeal to the emotions rather than to reason.

　　为达目的，它一定要诉诸人的情感而不是理性。

　　The doves appeal to softer emotions.

　　鸽派则求助于柔情策略。

　　2.dry up 枯竭;干涸

　　When remittances²² or credit sources dry up, women suffer.

　　当汇款和信贷源头干涸时，妇女们深受其害。

　　Antihistamines²³ can help dry up some mucus secretions²⁴.

　　抗组胺药物可以帮助干一些粘液分泌物。

　　3.as long as 只要；如果

　　It will prosper²⁵ as long as china does.

　　只要中国繁荣，澳大利亚就会兴旺发达。

　　Music has been with us as long as we can collectively remember.

　　只要音乐与我们同在，我们就会有共同的记忆。

　　4.able to 能；会

　　He was even able to build his own home.

　　他现在甚至能建一所自己的房子。

　　How fortunate that he had been able to love!

　　能爱别人是多么幸运的一件事！

1 reptilian   

adj.（像）爬行动物的；（像）爬虫的；卑躬屈节的；卑鄙的n.两栖动物；卑劣的人

参考例句：

• The chick is ugly and almost reptilian in its appearance. 这只小鸡长得很丑，看起来几乎像个爬行动物。 来自辞典例句
• Being from Orion do Zetas contain DNA from the Reptilian race? 齐塔人是从猎户座而来，DNA来自爬虫族吗？ 来自互联网

2 riddle   

n.谜，谜语，粗筛；vt.解谜，给…出谜，筛，检查，鉴定，非难，充满于；vi.出谜

参考例句：

• The riddle couldn't be solved by the child.这个谜语孩子猜不出来。
• Her disappearance is a complete riddle.她的失踪完全是一个谜。

3 precisely   

adv.恰好，正好，精确地，细致地

参考例句：

• It's precisely that sort of slick sales-talk that I mistrust.我不相信的正是那种油腔滑调的推销宣传。
• The man adjusted very precisely.那个人调得很准。

4 brackish   

adj.混有盐的；咸的

参考例句：

• Brackish waters generally support only a small range of faunas.咸水水域通常只能存活为数不多的几种动物。
• The factory has several shallow pools of brackish water.工厂有几个浅的咸水池。

5 zoologists   

动物学家( zoologist的名词复数 )

参考例句：

• Zoologists refer barnacles to Crustanceans. 动物学家把螺蛳归入甲壳类。
• It is now a source of growing interest for chemists and zoologists as well. 它现在也是化学家和动物学家愈感兴趣的一个所在。

6 gage   

n.标准尺寸，规格；量规，量表 [=gauge]

参考例句：

• Can you gage what her reaction is likely to be?你能揣测她的反应可能是什么吗？
• It's difficult to gage one's character.要判断一个人的品格是很困难的。

7 dissected   

adj.切开的，分割的，（叶子）多裂的v.解剖（动物等）( dissect的过去式和过去分词 )；仔细分析或研究

参考例句：

• Her latest novel was dissected by the critics. 评论家对她最近出版的一部小说作了详细剖析。
• He dissected the plan afterward to learn why it had failed. 他事后仔细剖析那项计划以便搞清它失败的原因。 来自《简明英汉词典》

8 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

9 reptiles   

n.爬行动物，爬虫( reptile的名词复数 )

参考例句：

• Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
• Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》

10 aquatic   

adj.水生的，水栖的

参考例句：

• Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
• We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。

11 puddles   

n.水坑， （尤指道路上的）雨水坑( puddle的名词复数 )

参考例句：

• The puddles had coalesced into a small stream. 地面上水洼子里的水汇流成了一条小溪。
• The road was filled with puddles from the rain. 雨后路面到处是一坑坑的积水。 来自《简明英汉词典》

12 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

13 strapped   

adj.用皮带捆住的，用皮带装饰的；身无分文的；缺钱；手头紧v.用皮带捆扎(strap的过去式和过去分词)；用皮带抽打；包扎；给…打绷带

参考例句：

• Make sure that the child is strapped tightly into the buggy. 一定要把孩子牢牢地拴在婴儿车上。 来自《简明英汉词典》
• The soldiers' great coats were strapped on their packs. 战士们的厚大衣扎捆在背包上。 来自《简明英汉词典》

14 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

15 secreting   

v.（尤指动物或植物器官）分泌( secrete的现在分词 )；隐匿，隐藏

参考例句：

• It is also an endocrine gland secreting at least two important hormones. 它也是一种内分泌腺，至少分泌二种重要的激素。 来自辞典例句
• And some calcite-secreting organisms also add magnesium to the mix. 有些分泌方解石的生物，会在分泌物中加入镁。 来自互联网

16 plentiful   

adj.富裕的，丰富的

参考例句：

• Their family has a plentiful harvest this year.他们家今年又丰收了。
• Rainfall is plentiful in the area.这个地区雨量充足。

17 physiologically   

ad.生理上，在生理学上

参考例句：

• Therefore, the liver and gallbladder cannot be completely separated physiologically and pathologically. 因此，肝胆在生理和病理上不能完全分离。
• Therefore, the liver and gallbladder are closely related physiologically and pathologically. 因此，肝胆在生理和病理上紧密联系。

18 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

19 outlet   

n.出口/路；销路；批发商店；通风口；发泄

参考例句：

• The outlet of a water pipe was blocked.水管的出水口堵住了。
• Running is a good outlet for his energy.跑步是他发泄过剩精力的好方法。

20 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

21 insufficient   

adj.(for，of)不足的，不够的

参考例句：

• There was insufficient evidence to convict him.没有足够证据给他定罪。
• In their day scientific knowledge was insufficient to settle the matter.在他们的时代，科学知识还不能足以解决这些问题。

22 remittances   

n.汇寄( remittance的名词复数 )；汇款，汇款额

参考例句：

• He sends regular remittances to his parents. 他定期汇款给他父母。 来自《简明英汉词典》
• Remittances sometimes account for as much as 20% of GDP. 在这些国家中，此类汇款有时会占到GDP的20%之多。 来自互联网

23 antihistamines   

n.抗组织胺药( antihistamine的名词复数 )

参考例句：

• Cough suppressants and some antihistamines may help quiet an annoying cough. 镇咳药和一些抗组织胺类药物能帮助驱除烦人的咳嗽。 来自互联网
• Antihistamines are the medications most commonly used to diminish allergic symptoms. 抗组胺药是药物最常用的，以减少过敏症状。 来自互联网

24 secretions   

n.分泌（物）( secretion的名词复数 )

参考例句：

• Lysozyme is an enzyme found in egg white, tears, and other secretions. 溶菌酶是存在于卵白、泪和其他分泌物中的一种酶。 来自辞典例句
• Chest percussion and vibration are used with postural drainage to help dislodge secretions. 在做体位引流时要敲击和振动胸部帮助分泌物松动排出。 来自辞典例句

25 prosper   

v.成功，兴隆，昌盛；使成功，使昌隆，繁荣

参考例句：

• With her at the wheel,the company began to prosper.有了她当主管，公司开始兴旺起来。
• It is my earnest wish that this company will continue to prosper.我真诚希望这家公司会继续兴旺发达。