Hi. Today we're going to be looking at animals in urban environments and I'm going to be telling you about some research on how they're affected by these environments.

大家好。今天我们将关注点放在（生活在）城市环境的动物上，我将向您讲述一些关于动物们如何被环境影响的研究。

Now, in evolutionary terms, urban environments represent huge upheavals, the sorts of massive changes that usually happen over millions of years.

如今，从进化的角度来看，城市环境意味着剧变，这种巨大的变化通常要经过数百万年。

And we used to think that only a few species could adapt to this new environment.

我们曾经认为只有少数物种能够适应这种新环境。

One species which is well known as being highly adaptable is the crow, and there've been various studies about how they manage to learn new skills.

一种众所周知的具有高适应性的物种是乌鸦，关于他们如何学习新技能已经有很多研究了。

Another successful species is the pigeon, because they're able to perch on ledges on the walls of city buildings, just like they once perched on cliffs by the sea.

另一种成功适应环境的物种是鸽子，因为它们能够栖息在城市建筑物墙壁的平台上，就像它们曾经栖息在海边的悬崖上一样。

But in fact, we're now finding that these early immigrants were just the start of a more general movement of animals into cities, and of adaptation by these animals to city life.

但事实上，现在我们发现这些城市早期的“移民”只是动物们大量迁移到城市的一个开端，也是这些动物适应城市生活的开始。

And one thing that researchers are finding especially interesting is the speed with which they're doing this - we're not talking about gradual evolution here - these animals are changing fast.

研究人员发现了一件特别有趣的事情，就是他们适应的速度——我们这里说的不是所谓的渐进式进化——而是这些动物正在快速改变。

Let me tell you about some of the studies that have been carried out in this area.

让我来为您介绍一些这方面正在进行的研究。

So, in the University of Minnesota, a biologist called Emilie Snell-Rood and her colleagues looked at specimens of urbanised small mammals such as mice and gophers that had been collected in Minnesota, and that are now kept in museums there.

在明尼苏达大学，一位名叫埃米莉·斯内尔·鲁德的生物学家和她的同事们观察了在明尼苏达州收集的城市化小型哺乳动物的标本，如小鼠和地鼠，现在这些标本被保存在当地的博物馆中。

And she looked at specimens that had been collected over the last hundred years, which is a very short time in evolutionary terms.

她看了过去一百年来收集的标本，从进化的角度来看，（一百年）是非常短的时间。

And she found that during that time, these small mammals had experienced a jump in brain size when compared to rural mammals.

她发现，在那段时间里，与农村哺乳动物相比，这些小型哺乳动物的大脑尺寸呈现大幅的增长。

Now, we can't be sure this means they're more intelligent, but since the sizes of other parts of the body didn't change, it does suggest that something cognitive was going on.

现在，虽然我们不能确定这意味着它们更聪明，但由于身体其他部位的大小没有改变，所以这的确表明认知方面正在改变。

And Snell-Rood thinks that this change might reflect the cognitive demands of adjusting to city life - having to look in different places to find food, for example, and coping with a whole new set of dangers.

斯内尔·鲁德认为，这种变化可能反映了适应城市生活的认知需求——例如，不得不在不同的地方寻找食物，并应对一系列全新的危险。

Then over in Germany at the Max Planck Institute, there's another biologist called Catarina Miranda who's done some experiments with blackbirds living in urban and rural areas.

在德国马克斯普朗克研究所，还有另一位名叫卡塔琳娜·米兰达的生物学家，她曾对生活在城市和农村地区的黑鸟做过实验。

And she's been looking not at their anatomy but at their behaviour.

而且她一直关注的不是它们的解剖，而是观察它们的行为。

So as you might expect, she's found that the urban blackbirds tend to be quite bold - they're prepared to face up to a lot of threats that would frighten away their country counterparts.

正如你所料，她发现城市黑鸟往往非常大胆——它们准备好面对许多威胁，而这些威胁往往会吓跑它们的乡村同伴。

But there's one type of situation that does seem to frighten the urban blackbirds, and that's anything new - anything they haven't experienced before.

但是有一种情况似乎确实会吓到城市黑鸟，那就是任何新情况（的出现）——任何他们之前没经历过的事情。

And if you think about it, that's quite sensible for a bird living in the city.

如果细想一下，对于生活在城市的鸟来说，这是相当合理的。

Jonathan Atwell, in Indiana University, is looking at how a range of animals respond to urban environments.

印第安纳大学的乔纳森·阿特威尔正在观察某一范围的动物如何应对城市环境。

He's found that when they're under stress, their endocrine systems react by reducing the amount of hormones such as corticosterone into their blood.

他发现，当它们处于压力之下时，他们的内分泌系统通过减少分泌到血液中的激素量，比如皮质酮的量，来做出反应。

It's a sensible-seeming adaptation.

这似乎是一种合理的适应性改变。

A rat that gets scared every time a subway train rolls past won't be very successful.

如果每次地铁驶过时老鼠都感到害怕，那它的适应就是不成功的。

There's just one more study I'd like to mention which is by Sarah Partan and her team, and they've been looking at how squirrels communicate in an urban environment, and they've found that a routine part of their communication is carried out by waving their tails.

我要提及的另一项研究是来自莎拉·帕坦和她的团队，他们一直在研究松鼠在城市环境中的沟通方式，他们发现它们沟通中日常的方式是摇动尾巴。

You do also see this in the country, but it's much more prevalent in cities, possibly because it's effective in a noisy environment.

你在乡村也能看到这个现象，但它在城市中更为普遍，可能是因为（这种方式）在嘈杂的环境中更加有效。

So what are the long-term implications of this?

那么这意味着什么呢？

One possibility is that we may see completely new species developing in cities.

一种可能性是，我们会看到全新的物种在城市中进化。

But on the other hand, it's possible that not all of these adaptations will be permanent.

但另一方面，很可能这些适应不是永久性的。

Once the animal's got accustomed to its new environment, it may no longer need the features it's developed.

一旦动物们习惯了新环境，可能就不再需要它之前进化出来的特征了。

So, now we've had a look ...

那么，现在让我们来看一下……