【英语时差8,16】纳塔耳分散现象：孩子们离家出走的时候

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Yaël: Hey Don, why the sad face?

 

Don: Yaël, I am beginning to think my son will never move out of the basement.

 

Y: I wouldn't worry. Natal¹ dispersal is a perfectly² natural thing.

 

D: Natal what?

 

Y: Natal dispersal. That's what happens when young animals leave home to make a life for themselves. Birds leave the nest. Mammals leave their home territories.

 

D: Do we know why they leave?

 

Y: Scientists think there are a number of reasons why young animals leave home. By 

doing so, they avoid competing with their relatives for resources. They avoid 

competing with each other for mates. And they also avoid inbreeding which can lead 

to less healthy offspring.

 

D: So, do all animals disperse³?

 

Y: Not all, but let's take bears as an example. Scientists have been keeping track of 

bear dispersal in many parts of the world. Most bears leave their mother's territory before they reach sexual maturity⁴ at age five. In Scandinavia, ninety-four percent of brown bear males and forty-one percent of females leave their natal territory. In Canada, grizzly⁵ bear males and females leave their mother's territory, but males leave in greater numbers and travel farther than females. In Virginia, black bear mothers  encourage their young to move away at one year of age and males even swim across   rivers to find a new home.

 

D: Hmm.

 

Y: You don't seem convinced.

D: Oh, I'm convinced.

 

Y: Then what is it?

 

D: Do scientists say anything about charging rent to encourage dispersal?

 

Y: I think that just might work for you, Don.  

 

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