经济学人250:谁吃了恐龙 What Ate Dinosaurs?

 　　What ate dinosaurs²?

　　谁吃了恐龙

　　Old crocs

　　古鳄鱼

　　Even in their heyday³, dinosaurs were not quite as dominant⁴ as popular myth makes them out to be

　　即便是在全盛时期，恐龙并非像民间传说所理解的那样占绝对统治地位

　　ONE answer to the question, “What ate dinosaurs?” is, obviously, “Other dinosaurs.” The ropod predators⁶ like Tyrannosaurus and Allosaurus loom⁷ large in the imagination of every lover of prehistoric⁸ monsters, and their animatronic fights with the likes of Diplodocus and Stegosaurus are the stuff of cliché. Science, though, tries to look beyond the obvious, and at this year’s meeting of the Society of Vertebrate Palaeontology, held in Las Vegas, some of the speakers asked whether the top predators of the Mesozoic era really were all dinosaurs. Their conclusion was “no”. Another group of reptiles⁹, until recently neglected, were also important carnivores. And it is a group that is still around today: the crocodiles.

　　“谁吃恐龙”很明显，其中一个答案是：“其它恐龙”每个史前怪兽爱好者的脑海里浮现出的是像霸王龙、翼龙这样的兽脚类掠食者，电脑制作的它们与梁龙、剑龙的打斗也成为俗套。而科学试图不落窠臼。今年，在拉斯维加斯召开的古脊椎生物学会会议上，一些发言人问到中生代顶级掠食者是否全是恐龙，结论是“否”。直到最近还被忽视的一类爬虫，同样是重要的食肉动物，正是仍然存活于今的一个族群：鳄鱼。

　　That the past role of crocodiles (or, strictly¹⁰, crocodilians, since they came in many sizes and shapes, not all of which resemble the modern animals) has been underestimated was suggested a few years ago by Paul Sereno. Dr Sereno, a palaeontologist at the University of Chicago, uncovered a crocodile-dominated ecosystem¹¹ from about 100m years ago (the middle of the Cretaceous period), in what is now north Africa. Besides water-dwelling giants similar to (though much bigger than) today’s animals, he found a range of forms including vegetarians¹² and species that ran on elongated¹³ legs—more like dogs than crocodiles. That discovery has prompted other fossil hunters to look elsewhere. As a result, even the well-studied rocks of North America are revealing that dinosaurs did not have it all their own way in the ecosystems¹⁴ of the Mesozoic—as Stephanie Drumheller of the University of Iowa and Clint Boyd of the University of Texas at Austin explained to the meeting.

　　几年前，芝加哥大学古生物学家保罗?赛伦诺博士提出鳄鱼过去的角色（或者从严格意义上讲是鳄鱼目动物，因为它们形状大小各异，并非所有都类似现代鳄鱼）被低估了，在今天的北非，他发现了一个一亿年前（白垩纪中期）由鳄鱼占主导地位的生态系统。除了与现代鳄鱼同为水生巨兽外（但远比现代的大），他还发现了一系列包括食草的、用长腿行走的——比起鳄鱼来更像狗的种群及形态。这一发现促使其他化石探寻者着眼于其它地方。结果是，即便是那些出自北美的已经研究得很透彻的化石也显示出恐龙并非占据中生代生态系统全部位置。——正如衣阿华大学的斯蒂芬妮?庄姆海勒以及位于奥斯汀的德克萨斯大学的克林特?博依德在会上说的那样。

　　The Cretaceous equivalent of zebra and antelopes—the victim species in every wildlife documentary about the dramas of the African savannah—were herbivorous dinosaurs called ornithopods. Frequently, these were taken by theropods. But not always. When Ms Drumheller and Mr Boyd examined the bones of juvenile¹⁵ upper-Cretaceous ornithopods dug up in Utah they saw marks on one skeleton that looked suspiciously like those modern crocodiles inflict¹⁶ when biting and tearing at their prey¹⁷. On examining these marks more closely, they found a crocodilian tooth stuck in one of them.

　　白垩纪被称为鸟脚亚目食草恐龙其地位相当于斑马和羚羊——每部有关非洲大草原的纪录片中被捕杀的种群。这些恐龙经常被兽脚亚目食肉恐龙捕食。但不总是这样，当庄姆海勒与博依德对犹他州出土的白垩纪年幼的鸟脚亚目食草恐龙的化石进行检查时，他们在一副骨架上发现了看上去像是遭受现代鳄鱼撕咬的痕迹。在对这些痕迹进一步检查后，他们发现一颗鳄鱼目动物牙齿嵌在其中一块骨头上。

　　Crocodile tears

　　鳄鱼的眼泪

　　It was not a large tooth. Its size suggests the animal which made it was no more than a metre and a half (about 5 feet) long. Such a predator⁵ would have been unable to take on an adult ornithopod. Nevertheless, this tooth is the first unarguable proof that crocodilians did indeed snack on dinosaurs. Moreover, it helps to confirm suspicions that the other crocodile-bite-like marks that Ms Drumheller and Mr Boyd have discovered really are what they look like. By combining that with an analysis of the whole site, the two researchers argue that what they have discovered is a dinosaur¹ nesting ground that was being raided by crocodilians.

　　这颗牙不是很大，其尺寸表明牙齿的主人不超过一米五（约五英尺）这样的掠食者本不能捕食一头成年鸟脚亚目食草恐龙。但无可争辩的是，这颗牙是第一个鳄鱼目动物拿恐龙当点心的证据。此外，这也有助于消除对庄姆海勒与博依德发现的其它看似鳄鱼咬痕的怀疑。结合对这个地区的分析，两位研究者认为他们所发现的是一个遭到鳄鱼目动物偷袭的恐龙筑巢地。

　　Such suspicions have been aroused before. Other sites in Utah are known to be dinosaur nesting grounds, since eggs are found there. Crocodilian bones frequently turn up at such sites. Ms Drumheller and Mr Boyd, however, seem to have nailed the connection down. Juvenile dinosaurs, at least, were indeed the prey of crocodilians. But what about adults?

　　这样的怀疑以前也出现过。由于发现了恐龙蛋，人们知道犹他州还有其它恐龙筑巢地。在这些地区，鳄鱼目动物化石经常被发现。可庄姆海勒与博依德像是要明确这一关系，年幼恐龙至少是鳄鱼目动物的猎物，那么成年的呢？

　　More than mere¹⁸ morsels¹⁹

　　不仅仅是少数

　　To investigate that question, Martin Lockley at the University of Colorado, Denver, and Spencer Lucas of the New Mexico Museum of Natural History and Science, turned to one of the most famous fossil phenomena²⁰ on the planet—the dinosaur freeway that runs through Colorado, New Mexico, Kansas and Oklahoma. This collection of tracks, scattered²¹ over several sites of the same age along the coast of an inland sea, is thought to mark an ancient migration²² route. The traces of more than 1,380 individual animals can be distinguished²³. Most, but not all, were ornithopods. Some were small carnivorous dinosaurs—the sort that might pick off young stragglers in the way that the crocodilians identified by Ms Drumheller and Mr Boyd did. But there is, Dr Lockley and Dr Lucas realised, something missing from the picture. When they looked for traces of big predatory dinosaurs, they found none.

　　为了弄清这一问题，丹佛科罗拉多大学的马丁?洛克里以及新墨西哥州自然历史博物馆的斯派瑟?卢卡斯将目光转向世上最著名的化石现象之一——横穿科罗拉多、新墨西哥、堪萨斯、俄荷拉荷玛的恐龙公路。于同一年代沿着一个内陆海海岸分布在数个地区，这一汇集恐龙踪迹的地区被认为是标出了一条古老的迁徙路线。人们能区分出超过1380种不同动物的踪迹。绝大部分是鸟脚亚目食草恐龙。一些是小型食肉恐龙——正如庄姆海勒与博依德所确认的鳄鱼目动物那样，这些恐龙会截杀年幼离群的食草恐龙。但洛克里与卢卡斯博士明白，图上遗漏了一些东西。当他们寻找大型掠食恐龙的线索时，他们什么也没发现。

　　That is ecologically absurd. Unless, of course, the top predator of the system—the one that could hunt down adult ornithopods—was not a dinosaur at all. And, when Dr Lockley and Dr Lucas re-examined the tracks they found that that was exactly what was going on. Instead of theropod footmarks, they found those of crocodilians. More than a quarter of the places where the dinosaur freeway surfaces have yielded signs of crocs. And they were big: sometimes more than four metres long. That is certainly large enough to take on an adult ornithopod.

　　从生物学上讲，这是荒唐的。当然除非生态系统的顶级掠食者——即是能捕杀成年的鸟脚亚目食草恐龙的——并不完全是恐龙。而且，当洛克里与卢卡斯博士对这些线索进行重新检查时，他们发现那正是曾经所发生的。在出土的恐龙公路上，超过1/4的地区已发现鳄鱼的踪迹。而且它们很大：有时超过4米长，大到足以捕杀一头成年鸟脚亚目食草恐龙。

　　Such megacrocs, then, could easily have acted as top predators in this ecosystem. But that does not completely explain the absence of theropod tracks. Modern migrating herbivores fall victim to many sorts of carnivore: big cats, wolves and hyenas²⁴, to name but three. The marshy²⁵ conditions of the dinosaur freeway (the reason its footprints formed, and have survived) may, though, have favoured crocodilians over predators that had evolved on drier land. In that sort of environment even a big theropod would constantly have been looking over its shoulder. Perhaps the real reason why they did not plant their footprints on the dinosaur freeway is that they might have ended up as prey, as well.

　　这样的巨鳄能在这样的生态系统中轻松担当顶级掠食者的角色。但这并不能完全解释兽脚亚目食肉恐龙的缺位。现代迁徙类食草动物成为众多食肉动物的牺牲品：大型猫科动物、狼、鬣狗，就拿这三样来说。然而，比起在干燥陆地上进化的掠食者，恐龙公路所处的湿地环境（形成并使恐龙足迹得以保存的原因）也许更受鳄鱼目动物欢迎。在那样一种环境下，即便是一头巨大的兽脚亚目食肉恐龙也会不时回头张望。它们为何没有在恐龙公路上留下足迹呢？真正的原因或许是它们同样亡于其它掠食者。

　　prehistoric adj. 史前的

　　underestimate v. 低估, 看轻

　　equivalent adj. 相等的

　　predator n. 掠夺者, 食肉动物

1 dinosaur   

n.恐龙

参考例句：

• Are you trying to tell me that David was attacked by a dinosaur?你是想要告诉我大卫被一支恐龙所攻击？
• He stared at the faithful miniature of the dinosaur.他凝视著精确的恐龙缩小模型。

2 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

3 heyday   

n.全盛时期，青春期

参考例句：

• The 19th century was the heyday of steam railways.19世纪是蒸汽机车鼎盛的时代。
• She was a great singer in her heyday.她在自己的黄金时代是个了不起的歌唱家。

4 dominant   

adj.支配的，统治的；占优势的；显性的；n.主因，要素，主要的人(或物)；显性基因

参考例句：

• The British were formerly dominant in India.英国人从前统治印度。
• She was a dominant figure in the French film industry.她在法国电影界是个举足轻重的人物。

5 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

6 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

7 loom   

n.织布机，织机；v.隐现，(危险、忧虑等)迫近

参考例句：

• The old woman was weaving on her loom.那位老太太正在织布机上织布。
• The shuttle flies back and forth on the loom.织布机上梭子来回飞动。

8 prehistoric   

adj.（有记载的）历史以前的，史前的，古老的

参考例句：

• They have found prehistoric remains.他们发现了史前遗迹。
• It was rather like an exhibition of prehistoric electronic equipment.这儿倒像是在展览古老的电子设备。

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 strictly   

adv.严厉地，严格地；严密地

参考例句：

• His doctor is dieting him strictly.他的医生严格规定他的饮食。
• The guests were seated strictly in order of precedence.客人严格按照地位高低就座。

11 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

12 vegetarians   

n.吃素的人( vegetarian的名词复数 )；素食者；素食主义者；食草动物

参考例句：

• Vegetarians are no longer dismissed as cranks. 素食者不再被视为有怪癖的人。
• Vegetarians believe that eating meat is bad karma. 素食者认为吃肉食是造恶业。

13 elongated   

v.延长，加长( elongate的过去式和过去分词 )

参考例句：

• Modigliani's women have strangely elongated faces. 莫迪里阿尼画中的妇女都长着奇长无比的脸。
• A piece of rubber can be elongated by streching. 一块橡皮可以拉长。 来自《用法词典》

14 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

15 juvenile   

n.青少年，少年读物；adj.青少年的，幼稚的

参考例句：

• For a grown man he acted in a very juvenile manner.身为成年人，他的行为举止显得十分幼稚。
• Juvenile crime is increasing at a terrifying rate.青少年犯罪正在以惊人的速度增长。

16 inflict   

vt.(on)把…强加给，使遭受，使承担

参考例句：

• Don't inflict your ideas on me.不要把你的想法强加于我。
• Don't inflict damage on any person.不要伤害任何人。

17 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

18 mere   

adj.纯粹的；仅仅，只不过

参考例句：

• That is a mere repetition of what you said before.那不过是重复了你以前讲的话。
• It's a mere waste of time waiting any longer.再等下去纯粹是浪费时间。

19 morsels   

n.一口( morsel的名词复数 )；（尤指食物）小块，碎屑

参考例句：

• They are the most delicate morsels. 这些确是最好吃的部分。 来自辞典例句
• Foxes will scratch up grass to find tasty bug and beetle morsels. 狐狸会挖草地，寻找美味的虫子和甲壳虫。 来自互联网

20 phenomena   

n.现象

参考例句：

• Ade couldn't relate the phenomena with any theory he knew.艾德无法用他所知道的任何理论来解释这种现象。
• The object of these experiments was to find the connection,if any,between the two phenomena.这些实验的目的就是探索这两种现象之间的联系，如果存在着任何联系的话。

21 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

22 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。

23 distinguished   

adj.卓越的，杰出的，著名的

参考例句：

• Elephants are distinguished from other animals by their long noses.大象以其长长的鼻子显示出与其他动物的不同。
• A banquet was given in honor of the distinguished guests.宴会是为了向贵宾们致敬而举行的。

24 hyenas   

n.鬣狗( hyena的名词复数 )

参考例句：

• These animals were the prey of hyenas. 这些动物是鬣狗的猎物。 来自辞典例句
• We detest with horror the duplicity and villainy of the murderous hyenas of Bukharinite wreckers. 我们非常憎恨布哈林那帮两面三刀、杀人破坏，干尽坏事的豺狼。 来自辞典例句

25 marshy   

adj.沼泽的

参考例句：

• In August 1935,we began our march across the marshy grassland. 1935年8月，我们开始过草地。
• The surrounding land is low and marshy. 周围的地低洼而多沼泽。