One of the most famous cases of extinction is that of a bird known as the dodo.

最著名的灭绝案例之一是一种名为渡渡鸟的鸟类。

In fact there's even a saying in English, 'as dead as the dodo', used to refer to something which no longer exists.

事实上，英语中甚至有一句俗语“像渡渡鸟一样死了”，用来指那些已经不存在的东西。

But for many centuries the dodo was alive and well, although it could only be found in one place, the island of Mauritius in the Indian Ocean.

虽然渡渡鸟只存在于一个地方——印度洋的毛里求斯岛，但是渡渡鸟也曾健康地生存了许多个世纪。

It was a very large bird, about one metre tall, and over the centuries it had lost the ability to fly, but it survived happily under the trees that covered the island.

这是一种体型非常庞大的鸟，大约一米高。几个世纪以来它已经失去了飞行的能力，但它在岛上的树木下快乐地生存了下来。

Then in the year 1507 the first Portuguese ships stopped at the island.

在1507年，第一艘葡萄牙船只在岛上停了下来。

The sailors were carrying spices back to Europe, and found the island a convenient stopping place where they could stock up with food and water for the rest of the voyage, but they didn't settle on Mauritius.

水手们正把香料运回欧洲，他们发现这个岛便于中途停留，在那里他们可以为余下的航程储备食物和水，但没有在毛里求斯定居下来。

However, in 1638 the Dutch arrived and set up a colony there.

然而，1638年荷兰人来到岛上并在那里建立了殖民地。

These first human inhabitants of the island found the dodo birds a convenient source of meat, although not everyone liked the taste.

这些第一批上岛定居的人发现虽然不是所有人都喜欢渡渡鸟的味道，但它们是很易得的肉类来源。

It's hard to get an accurate description of what the dodo actually looked like.

很难准确地描述渡渡鸟到底长什么样。

We do have some written records from sailors, and a few pictures, but we don't know how reliable these are.

我们确实有一些水手的笔记和照片，但我们不知道这些描述的可信度。

The best-known picture is a Dutch painting in which the bird appears to be extremely fat, but this may not be accurate – an Indian painting done at the same time shows a much thinner bird.

最著名的一幅画是荷兰的画，画中的鸟看起来非常胖。但这可能并不准确，因为在同一时期一幅印度画中的鸟就要瘦很多。

Although attempts were made to preserve the bodies of some of the birds, no complete specimen survives.

尽管有人试图保存一些鸟类的尸体，但都不完整。

In the early 17th century four dried parts of a bird were known to exist – of these, three have disappeared, so only one example of soft tissue from the dodo survives, a dodo head.17

世纪早期，有四块干燥的渡渡鸟碎片被保留下来。这其中的三块已经消失了，这样就只有一块来自渡渡鸟头部的软组织保留了下来。

Bones have also been found, but there's only one complete skeleton in existence.

人们也发现了一些渡渡鸟的骨骼，但是却只有一副完整的骨骼。

This single dodo skeleton has recently been the subject of scientific research which suggests that many of the earlier beliefs about dodos may have been incorrect.

这副渡渡鸟骨架最近成为科学研究的主题，这表明许多早期关于渡渡鸟的看法可能是不正确的。

For example, early accounts of the birds mention how slow and clumsy it was, but scientists now believe the bird's strong knee joints would have made it capable of movement which was not slow, but actually quite fast.

例如，早期对这种鸟类的描述提到了它是十分缓慢和笨拙的，但是科学家们现在相信，依靠强壮的膝关节，渡渡鸟的活动并不缓慢，相反还十分迅速。

In fact, one 17th century sailor wrote that he found the birds hard to catch.

事实上，一位17世纪的水手的记录中说到他发现这些鸟很难捕捉。

It's true that the dodo's small wings wouldn't have allowed it to leave the ground, but the scientists suggest that these were probably employed for balance while going over uneven ground.

的确，渡渡鸟的翅膀很小，不能飞离地面。但科学家们认为这些翅膀可能是在越过不平的地面时用来保持平衡的。

Another group of scientists carried out analysis of the dodo's skull.

另一组科学家对渡渡鸟的头骨进行了分析。

They found that the reports of the lack of intelligence of the dodo were not borne out by their research, which suggested the bird's brain was not small, but average in size.

他们发现他们的实验不能证明有关渡渡鸟智力不足的报道，这表明渡渡鸟的大脑并不小，而是中等大小的。

In fact, in relation to its body size, it was similar to that of the pigeon, which is known to be a highly intelligent bird.

事实上，从头身比来看，渡渡鸟的比例与鸽子很相似。众所周知鸽子是一种非常聪明的鸟。

The researchers also found that the structure of the bird's skull suggested that one sense which was particularly well-developed was that of smell.

研究人员还发现，这种鸟的头骨结构表明其嗅觉尤其发达。

So the dodo may also have been particularly good at locating ripe fruit and other food in the island's thick vegetation.

因此，渡渡鸟也可能特别擅长在岛上茂密的植被中找到成熟的水果和其他食物。

So it looks as if the dodo was better able to survive and defend itself than was originally believed.

因此，渡渡鸟看起来比人们最初猜想的更能擅长生存和自卫。

Yet less than 200 years after Europeans first arrived on the island, they had become extinct.

然而，距离欧洲人第一次来到岛上之后还不到200年，它们就灭绝了。

So what was the reason for this?

那么是什么原因导致了它们的灭绝呢？

For a long time, it was believed that the dodos were hunted to extinction, but scientists now believe the situation was more complicated than this.

很长一段时间以来，人们认为渡渡鸟是被猎杀而灭绝的，但科学家现在认为情况比这更复杂。

Another factor may have been the new species brought to the island by the sailors.

另一个因素可能是水手们带到岛上的新物种。

These included dogs, which would have been a threat to the dodos, and also monkeys, which ate the fruit that was the main part of the dodos' diet.

这其中包括威胁到渡渡鸟生存的狗。还有猴子，它们吃水果，这是渡渡鸟的饮食的主要来源。

These were brought to the island deliberately, but the ships also brought another type of creature – rats, which came to land from the ships and rapidly overran the island.

水手故意把这些动物带到岛上。但是船舶还带了了一个物种——老鼠。老鼠下船之后迅速蔓延到整个小岛。

These upset the ecology of the island, not just the dodos but other species too.

老鼠破坏了岛上的生态，不仅是渡渡鸟还有其他物种遭殃。

However, they were a particular danger to the dodos because they consumed their eggs, and since each dodo only laid one at a time, this probably had a devastating effect on populations.

然而，老鼠对渡渡鸟来说是特别的危险，因为它们吃掉了鸟蛋。另外由于每只渡渡鸟一次只产一只鸟蛋，这可能会对它们的种群产生毁灭性的影响。

However, we now think that probably the main cause of the birds' extinction was not the introduction of non-native species, but the introduction of agriculture.

但是，我们现在认为鸟类灭绝的主要原因可能不是引进非本地物种，而是引进农业。

This meant that the forest that had once covered all the island, and that had provided a perfect home for the dodo, was cut down so that crops such as sugar could be grown.

这意味着曾经覆盖全岛的森林被砍伐，以便种植诸如糖之类的作物。而这片森林曾为渡渡鸟提供了一个完美的家园。

So although the dodo had survived for thousands of years, suddenly it was gone.

所以尽管已经存活了几千年，渡渡鸟突然灭绝了。