生命的进化（1979）

a creature that has foregone the lush leaves of the grass
而专门吃草根
and specialised instead on eating the roots.
它勤劳地在地表以下几英寸挖洞
It tunnels industriously a few inches below the surface,
从下面咬下草根
nipping off the grass roots from beneath.
在地下眼睛没用了，鼹鼠彻底瞎了
Eyes are no use underground, and the mole rat has become totally blind,
它头上的毛皮完全遮盖了退化的眼睛
the furry skin of its head having completely covered the vestiges of its eyes.
它靠触摸找路
It finds its way around by touch,
利用头上两边成排的鬃毛
using lines of bristles growing on either side of its head.
它快活地穿梭于像轨道一样的洞穴 不但向前，也向后
It happily scuttles along its dark tunnels, not only forwards, but backwards, like a tram.
为了挖洞，它出色地用它那大而有力的啮齿
For burrowing it uses predominantly its large and powerful gnawing teeth
和铲子似的鼻子
and its shovel-shaped snout.
它在草地下挖了很长的洞穴并且看守它们
It excavates enormously long tunnels beneath the turf and guards them energetically
来保护从里面长出来的草根和球茎的供给
to protect its supply of roots and bulbs growing down from the ceiling.
如果鼹鼠在地道里遇见一个陌生人
If a mole rat meets a stranger in its tunnel,
很可能会有麻烦
there is likely to be trouble.
只要闻一闻，就知道是竞争对手
Having established by smell that they are rivals,
它们第一个反应是在两个领地之间建一道墙
their first reaction is to build a wall between the two territories.
若它们仍然闯进来，就会打起来
If they still run into one another, then they fight.
在春天，特大的土墩会出现在它们的通道上
In the spring, particularly large mounds appear above their runs,
雌鼹鼠把它们挪走， 就像挖养育它们的地方一样
thrown up by the females as they excavate their breeding chambers.
这些地下室都有装满球茎的贮藏室
Each of these underground mansions has larders stocked with bulbs,
有特别的厕所和通往雄性住处的通道
special lavatories and passages to the tunnels where the males live.
像父母一样瞎的小生命出生了并被养育
Here the young, blind like their parents, are born and reared.
鼹鼠是穴居动物中最专业的
Mole rats are the most dedicated of underground dwellers.
草原上的其他居住者，像这些土拨鼠一样
Other inhabitants of the plain, like these prairie dogs,
生活地更加大胆
are rather more confident about life.
土拨鼠也挖洞
Prairie dogs are also burrowers,
但它们不是花很多时间在地下而是地上
but they spend much of their time not below ground, but above it.
它们积极地开垦领地
They actively farm their fields.
如果有一种植物它们不喜欢吃 例如鼠尾草，就把根带走
If a plant they don't like to eat, such as sage, takes root on their land,
它们会把它咬下， 以便给它们喜欢的植物留空间
they will cut it down and so make room for more of the plants that they do like.
如果一片牧场变贫瘠了
If one patch of pasture gets overgrazed,
它们舍弃它，让它荒着而去开♥发♥另外一片
they abandon it and let it lie fallow while they feed on another patch.
它们生活在大几千倍的城镇里
They live in huge towns many thousands strong.
这些社区由30只动物组成
These great communities are made up of groups of about 30 animals,
它们各自都认识，经常洞穴间连通
which all know one another personally and often have interconnected burrows.
当邻居们见面时，它们亲吻和互相为对方清洁
When these neighbours meet, they kiss and groom one another.
它们交换许多种信息
They exchange many kinds of signals.
一个居民这样宣布他对洞穴的所有权：
A citizen declares his ownership of a burrow like this:
（尖叫声）
(SCREECHING)
当发现危险时，它们也发出危险警告
They also bark warnings when they spot danger,
例如在捕猎的鹰或狼
such as eagles or coyotes on the hunt.
（大叫）
(BARKING)
因而当大草原遍及世界时
So, as the open plains spread through the world,
离开森林开始吃草的动物 发展了不同的消化草的方式
the animals that left the forests to graze there developed different ways of digesting grass
并且在这危险的暴露的环境中保护自己
and of protecting themselves in this dangerously exposed environment.
在这期间，南美，我现在所在的地方
During this period, South America, where I am now,
像一个巨型岛屿一样被隔离
became isolated as a gigantic island.
巴拿马大♥陆♥桥沉没于♥大♥海♥之下
The land bridge of Panama sank beneath the sea.
切断了与其余世界的联♥系♥， 彭巴斯草原的动物
Cut off from the rest of the world, the inhabitants of these grasslands, the pampas,
发展出在我们眼中确实是很不寻常的物种
developed into forms that to our eyes seem very extraordinary indeed.
一种动物看起来像是骆驼和大象的过渡
One looked like a cross between a camel and an elephant.
比犀牛更大的食草动物
There were huge grazing beasts bigger than rhinos,
一种披甲动物，像小汽车一样的大小
and an armoured animal the size of a small car
像在骨质圆顶下运动的小汽车
that trundled about beneath a great dome of bone.
这些食草动物
These vegetarians were preyed on
被长着像短柄斧头的嘴但不能飞的大鸟捕食
by gigantic flightless birds with beaks like hatchets
有着军刀般牙齿的猎手，看起来像老虎
and hunters with sabre teeth that looked like tigers
把幼崽生在育儿袋里，像袋鼠
but bore their young in pouches, like kangaroos.
大约在五百万年前，这块土地和北美重新相连
But about five million years ago, the land link with North America was re-established
别的动物从北方转移到南方
and different creatures from the north moved south.
随着动物的混合
As the populations mixed,
北方动物和南方动物为了食物和领地而斗争
northerners and southerners competed for the same food and territory.
有胜者有败者，大部分南美的古怪动物消失了
There were winners and losers, and most of the strange South Americans disappeared.
但是在巴塔哥尼亚的这个巨大的洞穴里， 在这块大♥陆♥的南角
But in this gigantic cave in Patagonia, on the southern tip of the continent,
一个非常激动人心的生存铁证被找到
tantalising evidence has been found of a really dramatic survival.
在十九世纪末，一个德国人来到这儿
At the end of the 19th century a German came down here
定居这里并饲养牛羊
to settle and to ranch cattle and sheep.
并且这个洞穴就在他的大牧场里
And this cave lay on his estancia.
当它过去探查的时候， 它发现就在后面，在那一排大石头后面
When he came to explore it, he found, at the back, behind that line of boulders,
一堆极不寻常的骨头、皮肤和粪便
a pile of the most extraordinary bones, skin and dung.
它把一块皮肤挂在一根木桩上 来标记他土地的界限
He hung a piece of the skin on one of the posts that marked the boundary of his property.
几年之后，一个瑞士旅行家在那里发现了它
And there, a few years later, a Swedish traveller noticed it.
他把它送到伦敦的国家历史博物馆
He sent it to the Natural History Museum in London,
并在那里它被鉴定为属于一只巨型地懒
and there they identified it as belonging to a giant ground sloth.
从它的骨头化石中， 人们认识这种动物有一段时间了
This animal had been known for some time from its fossilised bones.
但那个洞里的遗迹并没有石化而且看起来很新
But the remains in the cave were not fossilised and seemed extraordinary fresh.
这种动物还没有可能在某些地方存活吗？
Could the animal still be alive somewhere?
为什么洞里会有如此大的一堆粪便？
Why were there such huge piles of dung in the cave?
成排的大石头有可能是人们建造的墙的遗迹吗？
Was it possible that the line of boulders was the remains of a wall built by men
这些动物像巨型牛一样地被圈养在洞里吗？
to pen the animals in the cave, like enormous cattle?
长♥期♥以来，没有人知道问题的答案
For a long time, nobody knew the answers to those questions.
但是最近的发掘已经至少弄清楚了一些事情
But recent excavations have at least cleared up some of them.
几年前，人们从这里挖出了这些小块的骨头
A few years ago, these bits of bone were dug up here.
这是一小块下颌，这是一小块股关节
This is a bit of the jaw, and this of the hip.
根据对它们的一些测试以及在地上的位置， 我们现在知道
From tests on them and their position in the ground, we now know
巨型树懒大约5000年前就在这里了
that the giant ground sloths were here up to about 5,000 years ago.
同样的发掘表明印第安人也在这里
The same excavations have also shown that the Indians were here
大约8000到1♥0♥0♥0♥0♥年前
between 8,000 and 10,000 years ago.
所以印第安人曾猎食那些大型动物 是极有可能的
So it is indeed possible that the Indians hunted those huge animals.
但那一排大石头，恐怕，
But that line of boulders, I'm afraid,
只不过是一次屋顶岩石的自然坠落
is no more than a natural fall of rock from the ceiling.
并且石头后的那堆粪便也不是什么迷团了
And the piles of dung behind it are no mystery either.
现在我们知道许多动物习惯 在同一堆粪便上排便
We now know that many animals habitually use the same dung hills,
并且，这些树懒可能冬天来这里取暖
and maybe the sloths came in here during the winter to keep warm.
但是恐怕这种动物现在的确灭绝了
But I'm afraid the animal is really now extinct.
不可能把一个有牛两倍大的动物
You can't hide a creature twice the size of a cow
藏在巴塔哥尼亚荒凉的狂野中
in the bleak emptinesses of Patagonia.
所以我们非常怀念我们上次有幸见到它
So we've missed our chance of seeing it.
但是无论如何，从地质角度上说， 它是一件很近的事
But it was quite a close thing, in geological terms, at any rate.
南美巨兽可能已经走了
The South American giants may have gone,
但一些没这么明显的 而又同样奇特的动物留了下来
but some less conspicuous but equally bizarre creatures remain.
有很多种类的犰狳，
There are many kinds of armadillos,
在南美大草原上小跑以及在森林里找食物
trotting over the pampas and foraging in the forests,
它们是巨大的灭绝了的动物的小型后代
diminutive descendants of the huge extinct ones.
也有一些很奇怪的啮齿类动物
There are some very odd rodents here, too.
这些是水豚。 它们在水中找掩护的地方
These are capybaras. They find safety in water.
像河马一样， 它们的眼睛、耳朵和鼻孔都在头顶
Like a hippopotamus, their eyes, ears and nostrils are all on the top of the head.
同样的原因，所以水豚能呆在水里
And for the same reason, so that the capybara can lie in the water
完全知道周围发生什么事情
fully aware of what's going on around it,
身体全部浸到水面以下
but with practically all its body hidden beneath the surface.
水豚是世界上发现的最大的啮齿动物
Capybaras are the largest rodents to be found anywhere in the world.
一只雄性可以长到三英寸长， 大约一米
A male grows to be three feet long, a metre or so,
它们是一种更大的已灭绝的祖先的后代
and they're the descendants of an even bigger extinct ancestor.
它们一个大家庭到处游动
They move around in large family groups
在很早的时候就是优秀的游泳者
and are excellent swimmers from an early age,
然而有时候小水豚发现更为容易的方法
though sometimes the young find even easier ways of getting around.
实际上它们除了吃一种或另外一种叶子以外， 什么都不吃
They eat virtually nothing except leaves of one sort or another,
不论是水生植物还是河岸上的草
either water plants or the grasses of the river bank.
兔鼠相当于南美的土拨鼠
The viscacha is the South American equivalent of the prairie dog,
尽管它大得多，相当于獾的大小
though it's very much bigger, about the size of a badger.
在黄昏，它从睡觉的地方爬上来环顾四周，
At dusk it comes up from its sleeping quarters and surveys the world
在开始它每晚啃草工作数小时之前
before starting on its nightly labour of nibbling grass for hours on end.
巴塔哥尼亚野兔，另一种啮齿动物， 有长长的腿
The mara, another South American rodent, has very long legs,
因为它寻找安全不是通过打洞而是逃跑
for it finds safety not by burrowing underground, but by running.
所以当它打洞时，它总是很警觉
So when it browses, it's always on the alert,
敏感地注视着危险 常常排成一列
nervously watching for danger and so highly strung
以至于它能从树枝的狭缝中穿梭 或是晕倒并喷出一种危险的气体
that it will race away at the crack of a twig or the faint whiff of a dangerous scent.
这种小的食叶者大约出现在5000万年前的北美
This little leaf-eater appeared some 50 million years ago in North America.
它不比一条西班牙猎犬大
It was no bigger than a spaniel,
它前腿有四个脚趾，后腿有三个