英语听力文摘 English Digest 355、狗为何会汪汪叫？（在线收听）

Why Dogs Bark?
犬吠为何？

Have you ever wondered why do dogs bark?

In terms of evolution, there has to be a reason for barking, or it probably wouldn’t be there. Is it to warn of predators? But dogs bark when there are no predators around. Is it play? Some dogs play without barking. In fact, people who study canine behavior find there isn’t much of a pattern to barking–it seems to be an all-purpose noise.

Now here’s another fascinating thing: adult wolves don’t bark. They growl, and they whine, but no barking. And dogs evolved from wolves. So where did the bark come in?

Mark Feinstein and Ray Coppinger of Hampshire College in Massachusetts have a theory. These biologists have noted that while adult wolves don’t bark, adolescents do. Wolf pup barking seems to be an intermediate noise you grow out of.

Now, a few tens of thousands of years ago, wolves and people started becoming friendly species. You can imagine a person tossing a bone to a friendly wolf from time to time. But “friendly” is the key. Nobody ever gets close to a hostile wolf. So over many thousands of years we would have been gradually selecting for certain behavioral traits–playfulness, low hostility, the ability to bond. Very puppy-like behaviors!

See what’s happening? A species that resembles a wolf puppy that never grows up may have slowly evolved in this way. That species would retain its puppy-like behaviors, such as barking, but never grow into growling, howling adult wolves. That species we would now call “dogs.”

你可曾想过犬缘何而吠呢？

从进化的角度来说，狗汪汪叫肯定是有理由的，要不这叫声肯定在漫长的进化过程中给淘汰掉了。那么这叫声是为了警告捕食者么？但是周围没有捕食者的时候狗也会汪汪叫。那么它只是在玩耍么？有些狗玩的时候也没有发出叫声呀。事实上，研究狗类行为的专家告诉我们，狗的叫声并没有固定的形式。它只是是一种多用途的响声。

另一件让人着迷的事情是：成年的狼并不会吠叫。它们只是嚎叫、哀鸣，但并不吠叫。但是狗是从狼进化而来的，那么，狗的这种吠叫声是从何而来的呢？

对此，来自马萨诸塞州罕布什尔学院的马克·范斯坦和雷·科平杰提出了一个理论。这两位生物学家注意到，虽然成年的狼不会吠叫，但是狼崽会。狼崽的吠声就好比是在它成长发声过程中的一个中间产物。（译者注：就好比我们在学习一门新的语言时产生的中介语）

现在我们来谈谈人的因素，数万年前，狼和人便开始进化成为可以友好相处的物种。你可以想象人们会时不时地向一只温顺的狼扔块骨头，但是“温顺”二字是关键，没人会靠近一只充满敌意的狼。因此，实际上，成千上万年以来，人类都在渐渐地、有意识地进行着选择，选择具有特定行为特征的狼群。这些特征包括爱嬉戏玩闹，温顺，合群。这些行为难道不像小狗吗？

现在明白这是怎么回事了吗？就像这样，一种类似于狼崽的物种开始慢慢的进化着。这一物种保留了那些幼崽般的行为特征，比如吠叫，它们也不会进化为嚎叫的成年狼。这一物种便是我们现在把它称之为“狗”的动物。