5 WHERE DID ALL THE ANIMALS GO

CHAPTER 4 WHERE DID ALL THE ANIMALS GO?

第四章所有的动物都去了哪里？

WHALE GRANDPA IN THE BEGINNING, HUMANS DIDN'T LIVE ALL OVER THE world—only in some parts. Our Sapiens ancestors lived in Africa, Neanderthals lived in Europe and the Middle East, Denisovans lived in Asia, and the small humans of Flores Island lived on Flores Island. In many other parts of the world, there were no humans at all. There were no humans in America or in Australia, or on many islands like Japan, New Zealand, Madagascar and Hawaii. This is because humans were not very good swimmers. They could sometimes reach islands that were really close to the mainland, like Flores, but they couldn't cross the open sea to reach places like Australia or Hawaii. When our Sapiens ancestors left Africa some 70,000 years ago, they started out by walking everywhere. They walked to Europe, where they met the Neanderthals; they walked to Asia, where they met the Denisovans; and they walked on and on until they reached the furthest end of Asia… and couldn't walk any further. But that didn't stop them because they now had a great idea. They knew that wood floats on water, so they tied logs together to make rafts, or they hollowed out tree trunks to make canoes—and they went to sea.

一开始，人类并没有遍布世界各地——只是在某些地方。 我们的智人祖先生活在非洲，尼安德特人生活在欧洲和中东，丹尼索瓦人生活在亚洲，弗洛雷斯岛上的小人类生活在弗洛雷斯岛上。 在世界上的许多其他地方，根本没有人类。 美洲、澳大利亚、日本、新西兰、马达加斯加和夏威夷等许多岛屿上都没有人类。 这是因为人类不擅长游泳。 他们有时可以到达离大陆很近的岛屿，比如弗洛雷斯岛，但他们不能穿过公海到达澳大利亚或夏威夷等地。 大约7万年前，当我们的智人祖先离开非洲时，他们开始四处行走。 他们走到欧洲，在那里他们遇到了尼安德特人；他们走到亚洲，在那里遇到了丹尼索瓦人；他们一直走啊走，一直走到亚洲的尽头，再也走不动了。 但这并没有阻止他们，因为他们现在有了一个好主意。 他们知道木头会浮在水面上，所以他们把原木绑在一起做木筏，或者挖空树干做独木舟——然后他们就出海了。

This was an amazing achievement. There are other animals that started out living on land and then evolved to live in the sea. For example, the ancient ancestors of whales were land animals that were no bigger than a large dog. Around 50 million years ago, some of these doglike animals started spending part of their time in rivers and lakes, hunting fish and other small creatures. Scientists discovered the skeleton of one of these animals in Pakistan, and they called it Pakicetus. The descendants of Pakicetus adapted to living in water; they spent more and more of their time in rivers, rarely venturing on to land. Their feet, which they no longer needed for walking, evolved into flippers. Their tails also changed to better help with swimming. Eventually, these animals swam out to sea: completely abandoning land, they spent their whole lives deep in the ocean. And their bodies adapted, growing enormous, until they became whales. But this process took millions and millions of years. Not one of the animals felt the change during his own lifetime. Not one of them started life as a small land animal and grew up to become a giant whale in the ocean. And none of them felt that they were a quarter-whale or a half-whale. At every step along the way, they were what they were, and that was good enough for them. If one of those doglike whale ancestors met a present-day whale, he would never guess that this giant sea monster was his relative. And whales are probably not the last step either. They might continue to evolve, and who knows what they'll look like in 50 million years! Unlike whales, Sapiens didn't have to wait for their bodies to evolve when they wanted to cross the sea; they just invented new tools. They didn't start growing flippers; they started building boats. And it didn't take them millions of years; it took just a few generations. When Sapiens first learned to build boats, they rowed to islands they could see from the shore. Then they rowed on, from one island to another, until they reached the farthest island. They couldn't see any more islands in the distance. Maybe this was the end of the world?

这是一个了不起的成就。 还有一些动物一开始生活在陆地上，后来进化到生活在海洋里。 例如，鲸鱼的古代祖先是陆地动物，不比一只大狗大。 大约5000万年前，这些像狗一样的动物开始在河流和湖泊中度过一部分时间，捕食鱼类和其他小型生物。 科学家们在巴基斯坦发现了其中一种动物的骨架，他们称之为巴基鲸。 巴基鲸的后代适应了生活在水中；他们在河中度过的时间越来越多，很少冒险上岸。 它们不再需要行走的脚进化成了鳍状肢。 它们的尾巴也发生了变化，以更好地帮助游泳。 最终，这些动物游向大海：完全抛弃陆地，它们一生都在海洋深处度过。 它们的身体适应了环境，长得越来越大，直到变成了鲸鱼。 但这个过程花了数百万年。 没有一只动物在自己的有生之年感受到这种变化。 它们中没有一个是从陆地上的小动物开始成长为海洋中的巨鲸的。 他们谁也不觉得自己是四分之一鲸或半鲸。 在这条路上的每一步，他们都是他们自己，这对他们来说已经足够好了。 如果那些像狗一样的鲸鱼的祖先遇到了现在的鲸鱼，它永远不会猜到这个巨大的海怪是它的亲戚。 鲸鱼可能也不是最后一步。 它们可能会继续进化，谁知道5000万年后它们会是什么样子！与鲸鱼不同，当智人想要穿越海洋时，他们不必等待身体进化；他们只是发明了新的工具。 它们没有开始长鳍状肢；他们开始建造船只。 它们并没有花几百万年的时间；只花了几代人的时间。 当智人第一次学会造船时，他们划船到岸上可以看到的岛屿。 然后他们继续划，从一个岛划到另一个岛，直到到达最远的岛。 他们再也看不到远处的岛屿了。 也许这就是世界末日？

But they didn't stop there. Perhaps some adventurous people said that there might be more islands hiding beyond the horizon. 'How do you know there are more islands?' their cautious friends asked. 'You haven't seen them'. 'How do you know there aren't more islands?' they replied. 'You haven't been there.' Anyway, a group of people must have decided to take the risk and sail into the unknown to see for themselves. They loaded as much food and water as they could on to their rafts and into their canoes and started rowing. And they rowed and rowed, until they could no longer see the island where their brave journey started… but they still couldn't see any new islands in the distance. And now their food and water were running low. If they went any further, they might not have enough provisions to make the journey back. What would you do if you were in one of those boats? Some of the adventurers probably thought it was too dangerous and turned back. But others decided to go on. Maybe one of them saw a bird flying up ahead and thought, 'That bird must be going somewhere, so there must be land ahead!' And on they rowed. And on. And on. Until they finally reached Australia. That was about 50,000 years ago. The journey made by the first people to reach Australia is one of the most important events in history. It's even more important than Columbus's journey to America, or the journey Neil Armstrong and his friends made to the Moon. The moment when the first humans set foot on an Australian beach was the moment when we humans became the most dangerous animal in the world—the rulers of planet Earth. Until then, humans had had a relatively small influence on their

但他们并没有就此止步。 也许有些爱冒险的人说，在地平线之外可能隐藏着更多的岛屿。 “你怎么知道还有更多的岛屿？”他们谨慎的朋友问。 “你还没见过他们呢。”“你怎么知道没有别的岛屿了？”他们回答说。 “你没有去过那儿。”无论如何，一定有一群人决定冒这个险，驶向未知的世界，亲自去看一看。 他们把尽可能多的食物和水装上木筏，装进独木舟，开始划船。 他们划啊划，划啊划，直到他们再也看不见他们勇敢旅程开始的那个岛屿，但他们仍然看不到远处有任何新的岛屿。 现在他们的食物和水都快用完了。 如果他们再往前走，他们可能没有足够的食物来返回。 如果你在其中一艘船上，你会怎么做？ 一些冒险家可能认为这太危险了，于是折回了。 但其他人决定继续前进。 也许他们中的一个看到一只鸟在前面飞，就想：“那只鸟一定要去什么地方，所以前面一定有陆地！”他们继续划着。 等等。等等。直到他们最终到达澳大利亚。 那是大约5万年前。 第一批到达澳大利亚的人的旅程是历史上最重要的事件之一。 它甚至比哥伦布的美洲之旅，或者尼尔·阿姆斯特朗和他的朋友们的月球之旅更重要。 第一批人类踏上澳大利亚海滩的那一刻，就是我们人类成为世界上最危险的动物——地球的统治者的时刻。 在此之前，人类对它们的影响相对较小