尼安德特人：为什么只剩下我们？

If a Neanderthal sat in today's subway, would people look at him?

Some scientists say: no.

People wouldn't give him a second glance.

He wears our clothes, rides our trains, and goes to work with us.

This idea is very interesting.

It shows that today's scientists increasingly feel that Neanderthals are a lot like us.

But many years ago, the story wasn't like this.

A hundred thousand years ago, several kinds of humans lived in the world.

Back then, humans were climbing a ladder step by step.

We were at the very top.

The others were at the bottom.

They weren't smart, so they didn't survive.

In the 19th century, people saw Neanderthal bones for the first time.

In the 1980s, many scientists thought this way.

Later, new discoveries came one after another.

In France, there is a cave called Bruniquel Cave.

One hundred seventy-six thousand five hundred years ago, Neanderthals walked into this cave.

They broke the stone pillars in the cave.

They used these stone pillars to make a circle.

Inside the circle there were also things that had been burned by fire.

Doing these things required planning, talking, and working together.

A scientist in London said: this shows they could think about very complex things.

Besides this cave, there is other evidence.

They could draw.

They cared for sick people.

They also used fire.

So some people started saying: they are just like us.

But others disagreed.

They said: this claim goes too far.

Maybe the Neanderthals learned things from us.

Maybe it was us who learned things from them.

It's hard for us to know who learned from whom.

In 2010, Neanderthal genes came out.

These genes tell us something important.

Neanderthals didn't directly turn into us.

They also didn't completely disappear.

Our ancestors had children with them.

Today, people outside Africa have about two percent Neanderthal genes in their bodies.

Neanderthal genes stayed on in this way.

Scientists also calculated a time span.

This interbreeding lasted about seven thousand years.

It started more than fifty thousand years ago.

But there are still many things we don't know.

How many times did this interbreeding happen?

Was it willing on their part?

Or was there violence?

A scientist who studies genes said: there is far too much we still don't know.

The first question people ask him is always: how many times were there between them and us?

This answer matters a lot.

If it was only a few times, then it's just a small event in history.

If it was thousands of times, then it's tied to who we are.

Besides genes, there are other reasons.

Back then, there were very few people.

The weather was very cold, and it changed a lot.

Sometimes the Neanderthals did well.

Sometimes we did well.

Sometimes the small groups on both sides died out.

Some say this was luck.

We came from Africa.

We had a larger population.

The places they lived had colder weather and were harder.

So maybe we were just a little luckier.

Others say it wasn't about luck.

Maybe our society was larger, with more friends.

Maybe we found it easier to cooperate.

Maybe we were better able to face new diseases.

None of these answers has been proven.

Now, scientists are still searching.

They put Neanderthal genes into mice.

They want to know what these genes do.

What we know now is: these genes are related to immunity, sleep time, and body shape.

But genes are only part of the story.

How people lived, how the weather changed, how many people there were — all of these matter.

Maybe the Neanderthals did nothing wrong.

They just didn't have the kind of luck we had.

They were in the world for four hundred thousand years.

We Homo sapiens, only three hundred thousand.

For a million years, there were many kinds of humans.

Human evolution spans seven million years.

Today, there are eight billion people in the world, all one kind of human.

They are gone.

We should think about it: will we be next?