What Happened to the Dinosaurs

What Happened to the Dinosaurs

恐龙灭绝之谜

What happened to the dinosaurs?

恐龙究竟怎么了 ?

Dinosaurs lived on Earth for 160 million years. Then, 65 million years ago, most of them disappeared. A few smaller ones slowly changed into the birds we have today. Other reptiles disappeared, too-flying reptiles and reptiles that lived in the sea. Many other kinds of animals also died out. And many kinds of plants.

恐龙在地球上生活了1.6亿年。然后，六千五百万年前，它们中的大部分消失了。一些较小的鸟慢慢地变成了我们今天看到的鸟。 其他爬行动物也消失了，飞行的爬行动物和生活在海里的爬行动物。许多其他种类的动物也灭绝了。还有很多种类的植物。

No one knows why the dinosaurs disappeared. But there are many different ideas. Scientists look at the evidence and try to decide which idea is right. Maybe small animals ate dinosaur eggs so only a few eggs were able to hatch. This is one idea. But it does not explain why other kinds of animals died out, and many plants as well. Also, some dinosaurs may not have laid eggs.

没有人知道恐龙灭绝的原因。不过,人们提出了许多不同的观点。科学家一直在寻找证据，试图确认哪种观点正确。 也许是有些小型动物吃掉了很多恐龙蛋,结果只有少数恐龙蛋能孵化出小恐龙。这是一种观点，但不能解释其他动植物灭绝的原因。另外，有些恐龙并不产蛋。

Maybe a group of dinosaurs got sick and the sickness spread to other groups. That's possible, for even today diseases spread among herds of cattle. But if that happened, chances are the sickness would not have reached reptiles that lived in the sea. Also, other kinds of animals would not have caught the sickness, and neither would plants.

也许是有一群恐龙生病了,还传染了其他恐龙群。这是有可能的。即便在今天,疾病仍然会在牛群中传染。如果是那样,生活在海洋里的爬行动物就不会感染疾病。其他种类的动物也不会得病，植物更不会。

Some scientists have another idea. They study fossils in very old layers of rock and in newer layers, too. They think they see signs that every 26 to 30 million years, different kinds of animals and plants have died out. Maybe every 26 to 30 million years showers of comets hit Earth. These comet showers would change Earth so much that many living things would not survive.

一些科学家提出了另一种观点。他们研究了古老岩层和较新岩层中的化石，认为找到了一些蛛丝马迹:每隔 2600 万至 3000 万年,就有许多不同种类的动植物灭绝。也许每隔2600 万至 3000 万年,彗星雨便会撞击地球。这些彗星雨使地球发生了翻天覆地的变化许多生物都没能存活下来。