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Narrator:Listen to part of a lecture in a Biology class.
獨白:聽下面一段生物課課堂上的講解。
Professor:OK. For today, let's look at a reptile, a predator that hasn't evolved much in the last seventy million years.
教授:好的，今天，我們來講一種爬行動物，這種食肉動物在過去的七千萬年中都沒有太大的進化。
No discussion of reptiles would be complete without some mention of crocodiles.
提到爬行動物就一定會談到鱷魚。
Now, we tend to think of crocodiles as, uh, kind of solitary, hiding out in a swamp, uh, kind of mysterious creatures.
現在我們通常認為鱷魚是一種孤僻的動物，他們隱藏在沼澤中，令人感覺十分神秘。
But we are finding out that they aren't as isolated as they seem.
但是我們發現鱷魚并不像大家想象的那樣孤僻。
In fact, crocodiles interact with each other in a variety of ways.
實際上，鱷魚之間的互動方式多種多樣。
One way is with vocalizations, you know, sounds generated by the animal.
其中一種就是發聲法，也就是動物發出的聲音。
This is true of the whole crocodile family, which includes crocodiles themselves, alligators, etc.
整個鱷魚族類都是如此，包括短吻鱷。
Take American alligators.
例如美洲鱷。
If you were to go to a swamp during the breeding season, you'd hear a chorus of sounds, deep grunts, hisses, these are sounds that male alligators make.
如果在繁殖季的沼澤中，你就會聽到各種聲音此起彼伏，低沉的咕嚕聲，嘶嘶聲，這些聲音都是雄鱷魚發出的。
And some of them are powerful enough to make the water vibrate.
而有的聲音大到可以引起水的震動。
This sends a strong, go-away message to the other males.
可以向其他雄性發出走開的信號。
So the alligator can focus on sending other sound waves through the water, sound waves that you and I couldn't even hear since they are at such low frequency.
這樣它就可以專注的通過水來發出其他的聲波，而由于這種聲波的頻率很低，我們大家都無法聽到。
But they do reach the female alligator, who then goes to find and mate with the male.
但是雌鱷魚可以接收到這種聲音，找到并與雄鱷魚交配。
Vocalization is um...well, it is used for other reasons, like getting attention or just, um... letting others know you are distressed.
發聲法也用在其他的季節，比如說引起注意，或者只是讓其他鱷魚知道他們很憂慮。
Let's see. New-born crocodiles, or hatchlings and their interactions with their mothers.
比如說，新生的鱷魚或剛孵出的小鱷魚與母鱷魚之間的溝通。
When they are born, croc... baby crocodiles have a sort of muffled cry while they are in their nest.
當小鱷魚剛出生的時候，他們會在巢穴中發出一種壓抑的聲音。
Hatchlings are really vulnerable, especially to birds and small mammals when they are born.
剛孵化的小鱷魚十分脆弱，尤其是面臨鳥類和小型的哺乳動物的威脅。
But their mother, who has been keeping vigil nearby, hears their cry for help and carries them to safety, meaning, to water.
但是他們的媽媽在附近守夜，聽到他們的叫聲后，就會將他們轉移到安全的地方，也就是水中。
So she takes them out of the nest.
她將他們從巢中帶出。
Uh, uh, all the eggs hatched at once, so she has about forty newborns to look after.
卵是一起孵化的，所以母鱷魚要照顧 40 只剛剛出生的小鱷魚。
Well, she takes about fifteen out of the nest at a time, carrying them in her mouth to the nearby water.
她一次可以轉移 15 只，將小鱷魚放在她的嘴里帶到附近的水中。
While she is taking one load of hatchlings, the others wait for her to come back.
當她將第一批新孵化的小鱷魚送到水里是，其他的小鱷魚就等待著她回來。
But do you think they are quiet about it?
但是你想他們會安靜的等著媽媽回來嗎？
No way. They are clamoring for the mother's attention, sort of squeaking and practically saying-don't forget about me!
當然不會。他們大叫著引起媽媽的注意，尖叫著就像是說別忘了還有我呢。
I heard some great examples of this on the television program on crocodiles last week.
上個星期我在電視上的一個有關鱷魚的節目上看到了不少這樣的例子。
Anyone catched it? It had a few interesting bits.
大家看到了嗎？里面有幾段非常有意思的畫面。
But you know, uh, you have to be careful, think critically.
但是你看節目的時候要仔細，抱著審視的態度。
Sometimes I don't know where these shows find their experts.
有時候我真不知道他們是從哪里請的專家。
Student:Excuse me. But, um... does all that crying defeat the purpose?
學生:不好意思。那他們的叫聲總能起到保護他們的作用嗎？
I mean, doesn't it attract more predators?
我是說，難道他們的叫聲不會引起其他食肉動物的注意嗎？
Professor:Hmm...good question.
教授:嗯，問得好。
I guess, well, I am guessing that once the babies have the mother's attention, they are safe.
我想如果小鱷魚引起了母鱷魚的注意，他們就是安全的。
She's never too far away, and, and I think...I mean, would you mess with a mother crocodile?
母鱷魚不會離開太遠的。我想，你會去惹一只母鱷魚嗎？
So after the mother transports all the youngsters, they still call to each other, and to their mother.
當母鱷魚將小鱷魚都轉移完畢，他們還會繼續叫嚷，跟其他的小鱷魚還有他們的媽媽。
This communication continues right through to adulthood.
這種交流一直會持續到他們成年后。
Crocodiles have about eighteen different sounds that they can make.
鱷魚能夠發出 18 種不同的聲音。
There's...um...um... you have deep grunting sounds, hisses, growls, are many different sounds to interact or send messages.
有低沉的咕嚕聲，嘶嘶聲，咆哮聲，還有許多不同的聲音來交流或傳遞信息。
This is more typical of mammals than of reptiles.
相比爬行動物，哺乳動物的聲音交流更具代表性。
I mean, crocodiles' brains are the most developed of any reptile.
我的意思是，在爬行動物中鱷魚的大腦是最發達的。
In that sense, they are closer to mammals' brains than other reptiles' brains.
在某種程度上，他們的大腦比其他爬行動物更接近哺乳動物。
And we know that mammals, dogs for example, dogs vocalize many different sounds.
而據我們所知，哺乳動物，比如說狗，能發出許多種不同的聲音。
Crocodiles have a similar level of, uh, vocal sophistication, if you will, which makes them unique among reptiles.
而鱷魚的發聲相對復雜，這使它在爬行動物中十分獨特。
Another thing would be, um, if a hatchling gets separated from the rest of its family, once the others get far enough away, its survival instinct kicks in.
還有一種情況，如果一只新生的鱷魚離開了它家族的巢穴，一旦達到一定距離，它的生存本能就會發揮出來。
It will make a loud distress call, which its siblings answer. It calls again.
它會發出很大的悲痛的叫聲，如果它的兄弟姐妹聽到了就會回應他，它就會繼續叫。
And they continue calling back and forth until they all find each other again.
它們會來回叫直到它們找到對方。
Another thing, something that wasn't on that TV show I mentioned.
還有另一種情況，是我提到的電視節目中沒有提到的。
Um...mother crocodiles lead their young from one area to another, like when they have to find a different source of water.
當母鱷魚帶領小鱷魚從一個地方轉移到另一個地方，比如說它們要尋找另一處水源。
Usually she will lead them at night, when it is safer for them, moving ahead and then letting out calls of reassurance so that they will follow her.
通常它們會在夜里行動，因為這時相對比較安全。母鱷魚在前面領路并發出叫聲以確認小鱷魚是否跟著她。
Her voice helps give the babies the courage they need to leave the area and go some place that's a more desirable home for them.
她的聲音會鼓勵小鱷魚，讓它們得到離開這個區域的勇氣，出發去其他更適合他們生存的地方。
