《趣味科普學英語》介紹
《趣味科普學英語》精選內容有趣的科普類話題，短短幾分鐘，讓你收穫的不僅僅是英語的提升，還有知識層面的擴充。真的是一舉多得！
導讀
什麼叫虎牙？人的嘴裡為什麼長虎牙？本期將介紹人類虎牙的進化和作用。
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中英文文本
Narrator: Lions have them, hippos have them,
獅子有 河馬有
and even you and I have them: canines,
甚至你和我都有 它們就是虎牙
those long, pointy front teeth.
這些又長又尖的前牙
They’re actually the longest teeth in the human mouth.
實際上是人類嘴裡最長的牙齒
So what are these long, sharp teeth doing
那麼 相比於嘴裡粗短的牙齒
among our short, stubby ones?
這些長而尖的牙齒是用來做什麼的呢？
Well, contrary to popular belief,
與人們普遍的看法相反
it’s not for tearing and ripping meat.
虎牙不是用來撕扯肉的
The real reason is actually much more romantic than that.
真正的原因其實要比這更加浪漫
為什麼人類擁有這些鋒利的前牙
Human men today have 10% longer canines than women,
現代男性的虎牙要比女性的長10％
and this difference isn’t unique to our species.
而且這種差別並不獨屬於人類
Our close relatives, gorillas,
我們的近親大猩猩
have it as well to an even larger extent.
它們之間的差別要比人類大得多
Males』 canines are twice as long as females』.
雄性的虎牙是雌性的兩倍長
That’s because in gorilla society,
因為在大猩猩的社會裡
males compete for exclusive mating rights to the entire female troop,
雄性大猩猩要為整個雌性群體的專屬交配權而競爭
and the male with the longest, most intimidating set of fangs usually wins.
擁有最長最嚇人犬齒的雄性大猩猩通常會取得勝利
Over time, gorillas have evolved increasingly longer canines,
隨著時間推移 大猩猩不斷進化出更長的虎牙
but when it comes to humans,
但一說到人類
our teeth took a different evolutionary path.
我們的牙齒選擇了一條不同的進化之路
Our canines have actually become shorter over time.
我們的虎牙隨時間地推移變得越來越短
Just look at the canines on the first human, Ardipithecus ramidus,
只要看一看最早的人類——地猿 就可以知道
or Australopithecus anamensis versus modern humans.
或者將湖畔南方古猿和現代人類進行對比
In fact, our canines today are the shortest they』ve ever been,
事實上 如今人類的虎牙是有史以來最短的
and the difference between male and female canines got less pronounced as well.
男女之間的虎牙差異也變得不那麼明顯
That’s because unlike modern gorillas
那是因為 與現代大猩猩不同
who take after our shared ancient ancestors,
雖然它們與人類共同的遠古祖先很像
human men eventually stopped fighting
但人類在牙齒的進化過程中
with their teeth somewhere along the way.
最終停止了使用牙齒來搏鬥
Now, scientists aren’t entirely sure why this happened,
科學家至今尚未完全確定其原因
but one possibility is that our babies grew increasingly defenseless,
但一種可能性是人類的嬰兒變得越來越弱小
so males had to spend more time on childcare
所以男性不得不花更多的時間照顧小孩
and less time on winning a mate.
花更少的時間去爭奪交配權
As a result, all that’s left in our mouths today
結果是 如今我們嘴裡所留下的
is the memory of a more slobbery method of one awing our peers.
更多只是個噴著口水嚇唬同類的記憶而已
That’s right, those canines you carry around today aren’t particularly useful.
確實 如今你擁有的虎牙並不是特別有用
For one thing, they’re not long enough to grab
一方面 人類的虎牙不夠長
and hold on to prey the way lions use them,
不能像獅子那樣用來抓捕和控制獵物
and they’re not big enough to intimidate predators 『 arrivals the way hippos use them.
也不夠大 不能像河馬一樣用來嚇退捕食者
Instead, they help us bite into food. That’s it.
但它們能幫助我們咬入食物 如此而已
Turns out, evolution isn’t always useful,
事實證明 進化不總是有用的
but while the truth about our canines might be disappointing,
儘管人類虎牙的真相會讓人失望
those teeth are still pretty amazing
但這些牙齒依然讓人感到十分震驚
because anthropologists use canine size and shape
因為人類學家利用虎牙的大小和形狀
to help track when humanlike ancestors evolved.
來幫助追蹤類人祖先進化的時間
So in a way, our tiny canines make us who we are.
所以在某種程度上 是小小的虎牙造就了今天的我們