【英语时差8,16】为何狗要咆哮（下）

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 hostility¹, 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 growling², howling adult wolves. That species We would now call that species “dogs.”

1 hostility   

n.敌对，敌意；抵制［pl.］交战，战争

参考例句：

• There is open hostility between the two leaders.两位领导人表现出公开的敌意。
• His hostility to your plan is well known.他对你的计划所持的敌意是众所周知的。

2 growling   

n.吠声, 咆哮声 v.怒吠, 咆哮, 吼

参考例句：

• We heard thunder growling in the distance. 我们听见远处有隆隆雷声。
• The lay about the deck growling together in talk. 他们在甲板上到处游荡，聚集在一起发牢骚。