and even you and I have them: canines.

甚至你我都有：犬齒。

Those long, pointy front teeth,

那些長長尖尖的牙齒，

they're actually the longest teeth in the human mouth.

其實是人類口中最長的牙齒。

So what are these long, sharp teeth

那麼這些長尖牙

doing among our short, stubby ones?

在我們粗短的牙齒之中有何功能呢？

Well, contrary to popular belief,

與多數人的認知相反，

it's not for tearing and ripping meat.

並不是用來撕扯肉。

The real reason is actually much more romantic than that.

真實的理由其實比那浪漫多了。

Human men today have 10% longer canines than women,

現代人類男性犬齒比女性的長了 10%，

and this difference isn't unique to our species.

而這個差異並非人類獨有。

Our close relatives, gorillas, have

我們的近親，大猩猩，也有

it as well to an even larger extent.

甚至差異更懸殊。

Males' canines are twice as long as females'.

雄性的犬齒是雌性的兩倍長。

That's because in gorilla society,

那是因為在大猩猩的社會裡，

males compete for exclusive mating rights to

雄性競爭唯一與整群母猩猩

the entire female troop, and the male

交配的權利

with the longest, most intimidating

而擁有最長、最有威脅力的一副尖牙

set of fangs usually wins.

的雄性通常會勝出。

Over time, gorillas have evolved increasingly longer canines,

隨著時間，大猩猩演化出了更長的犬齒，

but when it comes to humans, our teeth

至於人類，我們的牙齒

took a different evolutionary path.

走上一條不同的演化道路。

Our canines have actually become shorter over time.

事實上，我們的犬齒隨著時間變得更短了。

Just look at the canines on the first human,

看看第一個人類，

Ardipithecus ramidus,

地猿、

or Australopithecus anamensis versus modern humans.

或是湖畔南方古猿，相較於現代人的犬齒。

In fact, our canines today are the shortest

事實上，我們現在的犬齒是

they've ever been, and the difference

歷代以來最短的，

between male and female canines

且雌雄犬齒之間的差異

got less pronounced as well.

也變得不那麼明顯。

That's because unlike modern gorillas

那是因為不像現代的大猩猩

who take after our shared ancient ancestors,

仿效了我們共同的祖先，

human men eventually stopped fighting

人類男性在演化路上某處

with their teeth somewhere along the way.

最終停止了用牙齒打架。

Now, scientists aren't entirely sure why this happened,

現今，科學家並未完全明瞭箇中原因，

but one possibility is that our babies

但有一個可能是我們的嬰兒

grew increasingly defenseless, so males

愈來愈無防備，所以男性

had to spend more time on childcare

必須花更多時間照顧小孩

and less time on winning a mate.

較少時間在贏得交配權。

As a result, all that's left in our mouths today

結果，現在留在我們口中的

is the memory of a more slobbery method

是用更多口水的方式

of one-upping our peers.

贏過我們同輩的紀念。

That's right, those canines you carry

沒錯，你現在的那些

around today aren't particularly useful.

犬齒並不特別有用。

For one thing, they're not long enough

一方面，它們不像獅子

to grab and hold on to prey the way lions use them,

夠長去掠奪並抓住獵物，

and they're not big enough to intimidate

也不像河馬

predators' arrivals the way hippos use them.

夠大足以威脅掠食者。

Instead, they help us bite into food. That's it.

它們幫助我們咬食物，僅此而已。

Turns out, evolution isn't always useful,

結果，演化並非總是有用，

but while the truth about our canines

但即使關於我們犬齒的事實

might be disappointing, those teeth

可能令人失望，那些牙齒

are still pretty amazing because

仍然很了不起，因為

anthropologists use canine size and shape

人類學家利用犬齒的大小和形狀

to help track when humanlike ancestors evolved.

協助追蹤人類祖先的演化。

So in a way, our tiny canines make us who we are.

所以在某種意義上，我們小小的犬齒造就了現在的我們。