为了帮助大家更好的备考雅思听力，使雅思听力这个问题得到彻底解决，从现在开始，小编开始陆续为大家准备了一些雅思考试听力真题。
Hi. Today we're going to be looking at animals inurban environments
嗨。我们今天讲的是城市中的动物，
and I'm going to be telling you about some researchon how they're affected by these environments.
我会说一些关于它们是如何被环境影响的研究。
Now, in evolutionary terms, urban environmentsrepresent huge upheavals,
用进化的术语来说的话，城市的环境代表着很大的变动，
the sorts of massive changes that usually happenover millions of years.
就是那种经过数百万年才会造成的巨大改变。
And we used to think that only a few species could adapt to this new environment.
我们曾经觉得只有很少生物能够适应这种新环境。
One species which is well known as being highly adaptable is the crow,
众所周知的适应性极强的物种之一就是乌鸦，
and there've been various studies about how they manage to learn new skills.
也有很多关于它们如何学习新技能的研究。
Another successful species is the pigeon, because they're able to perch on ledges on the wallsof the city buildings,
另一个非常成功的物种是鸽子，因为它们能够在城市建筑物的墙架上栖息，
just like they once perched on the cliffs by the sea.
就像它们经在海边的悬崖上栖息一样。
But in fact, we're now finding that these early immigrants were just the start of a more generalmovement of animals into cities,
但是实际上，我们如今发现这些早期的"移民"只是向城市移居的一大群动物的一小部分而已，
and of adaptation by these animals to city life.
也只是这些动物们适应城市生活的一部分而已。
And one thing that researchers are finding especially interesting is the speed with which they'redoing this
研究者发现一件特别有趣的事情，那就是它们适应的速度
we're not talking about gradual evolution here -- these animals are changing fast.
我们指的并不是逐渐的进化--这些动物进化的非常快。
Let me tell you about some of the studies that have been carried out in this area.
让我来告诉你一下这个领域开展的一些研究。
So, in the University of Minnesota, a biologist called Emilie Snail-Rood and her colleagues lookedat specimens of urbanized small mammals
所以，在明尼苏达大学，一名叫做Emilie Snail-Rood的生物学家和她的同事们研究了城市化的小型哺乳动物的样本，
such as mice and gophers that had been collected in Minnesota, and that are now kept inmuseums there.
比如说老鼠和囊地鼠，这些样本都是从明尼苏达收集的，现在保存在那里的博物馆里面。
And she looked at specimens that had been collected over the last hundred years, which is avery short time in evolutionary terms.
她也研究了过去几百年来收集的样本，在进化意义上，这段时间很短。
And she found that during that time, these small mammals had experienced a jump in brainsize when compared to rural mammals.
她发现，在那段时间，和农村地区的动物相比，这些小型哺乳动物的脑部大小迅速增加。
Now, we can't be sure this means they're more intelligent,
我们不能确定这就意味着它们变得更加聪明，
but since the sizes of other parts of the body didn't change, it does suggest that somethingcognitive was going on.
但是因为身体的其他部分大小并没有改变，这确实能够暗示着发生了一些认知方面的变化。
And Snell-Rood thinks that this change might reflect the cognitive demands of adjusting tocity life
Snell-Rood认为这些变化可能反映了适应城市生活的认知变化
having to look into different places to find food, for example, and coping with a whole new setof dangers.
比如说，需要"考察"不同的地方来寻找食物，以及应对一些新的危险。
Then over in Germany at the Max Planck Institute,
然后在德国的马克斯--普朗克研究所，
there's another biologist called Catarina Miranda who's done some experiments with blackbirdsliving in urban and rural areas.
有一位名为Catarina Miranda 的生物学家，她做了关于生活在城市和农村地区的黑鹂的实验。
And she's been looking not at their anatomy but at their behaviour.
她所关注的不是它们的结构，而是它们的行为。
So as you might expect, she's found that the urban blackbirds tend to be quite bold
可能如你所料，她发现城市的黑鹂会更加大胆
they're prepared to face up to a lot of threats that would frighten away their countrycounterparts.
它们不惧很多挑战，而这些挑战可能会吓坏它们的乡村同伴。
But there's one type of situation that does seem to frighten the urban blackbirds,
但是也有一种情况能够吓到城市的黑鹂，
and that's anything new -- anything they haven't experienced before.
那就是全新的情况--这种情况它们从来没有遇到过。
And if you think about it, that's quite sensible for a bird living in the city.
如果你想一下的话，对于一只在城市生活的鸟来说，那是完全合乎情理的。