英语听力：自然百科 黄石公园的夏天 Yellowstone—3

 This mother bear's experience gives her family a good chance of survival until spring arrives. They will return again and again as the thaw¹ releases more fish. 

 

On the warmer plains and valleys that surround the plateau, grazers are on the move. They left the high country to avoid the worst of the winter and now begin the long journey towards the heart of Yellowstone in time for summer. These elk² are led by experienced adults who have made this trip many times before.

 

They are followed on their migration³ by the most ancient American grazers, pronghorn. Though predators⁴ may follow, none can outpace them. Over distance, these are the fastest animals in the world, taking the long migration in their stride.

 

Migrating elk and pronghorn must follow the advancing thaw, but higher up in the valleys, one animal is well ahead of them. Bison are adapted for cold. These herds⁵ need to be in Yellowstone early to have time to bring up their young in the short summer ahead.

 

1 thaw   

v.（使）融化，（使）变得友善；n.融化，缓和

参考例句：

• The snow is beginning to thaw.雪已开始融化。
• The spring thaw caused heavy flooding.春天解冻引起了洪水泛滥。

2 elk   

n.麋鹿

参考例句：

• I was close enough to the elk to hear its labored breathing.我离那头麋鹿非常近，能听见它吃力的呼吸声。
• The refuge contains the largest wintering population of elk in the world.这座庇护所有着世界上数量最大的冬季麋鹿群。

3 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。

4 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

5 herds   

兽群( herd的名词复数 )； 牧群； 人群； 群众

参考例句：

• Regularly at daybreak they drive their herds to the pasture. 每天天一亮他们就把牲畜赶到草场上去。
• There we saw herds of cows grazing on the pasture. 我们在那里看到一群群的牛在草地上吃草。