考研英语外刊阅读能力的提升，需要日积月累才能看得到效果。接下来，北京文都考研网为帮助2020考研学子，在英语水平上更上一层台阶，特意整理出考研英语外刊阅读精选:食草系鳄鱼，供考生参考。
2020考研英语外刊阅读精选:食草系鳄鱼
Compared with mammals, living members of the crocodile clan have exceptionally boring dentition.
和哺乳动物相比，现存鳄鱼家族的成员有着异常无趣的牙列。
From the slender-snouted gharials of India and the nocturnal caimans of South America to the saltwater behemoths of the South Pacific,crocodile teeth vary little in morphology.
从印度的非洲狭吻鳄和南美的夜行凯门鳄到南太平洋的盐水巨兽，鳄鱼的牙齿形态变化不大。
All are conical and pointed. Each tooth in an animal's mouth is almost identical to its neighbours—as befits a group of that feed on a mixture of fish and the occasional careless beast that strays too close to the shore, or even into the water itself.
它们所有类型的牙齿都是圆圆尖尖的。动物嘴里的每颗牙齿几乎都和它的邻居一样— 这群动物以各种鱼以及因粗心而偶尔 离海岸太近或者甚至游到水里去的野兽为食。
This predilection for pointed fangs is not, however, how it has always been. During the days of the dinosaurs, the Jurassic and Cretaceous periods,crocodile-clan members showed extraordinary dental diversity.
但对尖牙的这种偏爱并非一直如此。在恐龙时代,侏罗纪和白垩纪， 鳄鱼家族成员的牙齿展现出了非凡的多样性。
Many of their teeth have proved so bizarre that some palaeontologists have theorised that,far from being carnivorous, these ancient species might have been eating plants.
它们的许多牙齿被证明是非常怪异的，以至于一些古生物学家推断，这些远古物种根本不是食肉动物，它们可能以植物为食。
A study published this week in Current Biology, by Keegan Melstrom and Randall Irmis at theUniversity of Utah, confirms this. It also suggests that herbivory evolved in the crocodile clan on several occasions.
本周犹他大学的Keegan Melstrom和Randall Irmis在《Current Biology》发表的一项研究证实了这一点。该研究还表明鳄鱼家族的食草性进化了好几次。
When trying to work out what ancient animals ate, palaeontologists usually look to modern analogues. If teeth from an extinct beast match those of a modern species, the two are quite likely to have had similar diets.
当古生物学家试图弄清楚古代动物吃什么时，他们通常会参照现代的类似物。如果灭绝动物的牙齿与现代动物的牙齿相匹配，那么这两种动物很可能有着相似的饮食习惯。
With extinct crocodilians, however, this palaeontological tactic has routinely been stymied because their teeth, which are adorned with many rows of cusps and wrinkled enamel, look nothing like what is found in the mouths of animals alive today.
但对于已经灭绝的鳄鱼来说，这种古生物学策略经常受到阻碍因为它们的牙齿上布满了一排排的牙尖和皱巴巴的牙釉质 看起来一点也不像在今天活着的动物嘴里发现的东西。
This has left the topic of what ancient crocodilians ate very much up for grabs. Some palaeontologists argue that certain species, such as Simosuchus clarki were vegetarian.
这就留下了古代鳄鱼吃什么的话题。一些古生物学家认为某些种类，如迷你鳄鱼是素食动物。
To solve the puzzle Mr Melstrom and Dr Irmis turned to Orientation Patch Count Rotated(OPCR) analysis. This technique scans a tooth and measures the complexity of its surfaces.
为了解决这个难题，Melstrom和Irmis博士转向了旋转定位补丁计数(OPCR)分析。这项技术扫描牙齿并测量其表面的复杂性。
Use of OPCR has demonstrated, in a quantifiable manner, that diet is closely related to tooth complexity. Carnivores tend to have simple teeth. Omnivores have more complex teeth. Herbivores have the most complex teeth of all.
OPCR的使用以可量化的方式证明，饮食与牙齿复杂性密切相关.食肉动物的牙齿比较简单。杂食动物的牙齿更复杂。食草动物的牙齿是所有牙齿中最复杂的。
Until now, however, the technique has been used mostly on the molars of living mammals. Indeed, Mr Melstrom and Dr Irmis knew of no studies that had tested it extensively oncrocodiles and their kin.
但直到现在，这项技术主要用于现存哺乳动物的臼齿。事实上，Melstrom和Irmis博士都不知道有任何研究对鳄鱼及其近亲进行的广泛测试。
This lack of testing made sense, because living crocodilians have no complex tooth morphologies to analyse—so why bother?
缺乏这种测试是有道理的，因为现存的鳄鱼没有复杂的牙齿形态来分析，所以为什么要麻烦呢?
However, the strange teeth of ancient crocodiles, they reasoned, might give OPCR something to work with. In total, they threw 146 teeth from16 extinct crocodilians at OPCR.
但他们推断，远古鳄鱼奇怪的牙齿可能会给OPCR提供一些启发。他们一共对16只灭绝鳄鱼的146颗牙齿进行OPCR分析。
For comparison, they also added teeth from a modern caiman into the mix. The analysis revealed that two of the extinct species were, like the caiman, carnivorous.
为了进行对比，他们还加入了现代凯门鳄的牙齿。分析显示，其中两个灭绝的物种，和凯门鳄一样，是食肉动物。
But even these were notably different from modern animals in that one had serrated steak-knife-like teeth and the other had triangular teeth that made contact with one another when the animal closedits mouth(something not seen in modern crocodilians).
但即使是这些动物也与现代动物有明显的不同，一种动物有锯齿状的牛排刀状牙齿， 另一种动物有三角形的牙齿，当动物的嘴闭上时，这些牙齿就会互相接触 (这是现代鳄鱼所没有的)。
The system identified two of the species as"durophagus", meaning that their teeth looked as if they would be good at crushing the shells of clams, crabs and other armoured invertebrates.
系统鉴定出其中两种为“具有硬壳或外骨骼的生物体”， 这意味着它们的牙齿似乎很擅长咬碎蛤蜊、螃蟹和其他甲壳类无脊椎动物的外壳。
One species was identified as omnivorous. And eight, including Simosuchus, were identifiedby OPCR as obligate herbivores. (The other three were hard to classify, but may have been insectivores.)
一种被鉴定为杂食动物。八种，包括迷你鳄鱼，被OPCR鉴定为专性食草动物。(其他三只很难分类，但可能是食虫动物。)
What particularly surprised Mr Melstrom and Dr Irmis, though, was the way herbivory mapped onto the crocodile family tree.
让Melstrom和Irmis博士感到特别惊讶的是这种食草性映射在鳄鱼族谱上的方式。
Rather than evolving once at some point long ago and then appearing in all later species on that branch, it came into existence at least three times during the history of these reptiles.
这种食草性不是在很久以前的某个时候进化过一次，然后出现在那个分支上的所有后来的物种中， 而是在这些爬行动物的历史中至少出现过三次。
Herbivorous crocodiles of the Jurassic and Cretaceous, then, were capable of competing successfully with their dinosaur counterparts in a way that a modern herbivorous crocodile presumably could not with the plethora of herbivorous mammals that now exists.
侏罗纪和白垩纪时代的食草鳄鱼 能够成功地与它们的恐龙同伴竞争。但现代食草鳄鱼可能无法用这种方式和现存的过多的食草哺乳动物成功竞争。
以上是北京文都考研网给出的“2020考研英语外刊阅读精选:食草系鳄鱼”，希望对2020考研者有所帮助!祝2020考研成功!
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