英语听力:自然百科 大迁徙 Great Migrations—9(在线收听

 Females travel in family groups, sometimes leading their young on yearly wanderings of up to 20,000 miles. Each day, they gather to reaffirm their bonds. They seem to crave physical contact.  

 
Finally, the mothers disperse to feed in shifts. They leave their calves for up to 40 minutes of every hour. They may dive up to 2 miles for a daily catch of 300 pounds of octopus and squid. This calf, too young to dive, tracks his mother closely from above, listening intently for her signature clicks.
 
Chunks of octopus rise to the surface from the matriarchs hunting below like bread crumbs leading back to safety. 
 
From the depths, mother finally returns. All of this young life, the calf has been on the move. Now his mother and aunts seem to be waiting for something big. Unknown to the calf, he’s about to be welcomed into a world of giants, a world rarely seen and little understood. 
 
Migrations are "journeys of attrition. Darwinian in the extreme".
  原文地址:http://www.tingroom.com/lesson/zrbaike/2010/259337.html