英语听力：2013-04-14 恐龙之战之极限生存 Extreme Survivors—12

 Like sea turtles who from the moment they hatch they are on their own. For predators¹, hatching time is a veritable feast. Even so, the strategy works. Carnivores gulp² down virtually every hatchling, but a few do make it, not even the most voracious³ feeders can kill them all.

 

Sauropods were in a predator-rich environment, so I’m sure that many, many Sauropods nests were found and destroyed by predators before the babies could even hatch. 

 

Sauroposeidon’s size is its main defense⁴. When it reaches an adult weight of 50 tons, nothing can touch it. But maintaining this massive girth means filling up almost constantly. An adult will eat almost anything that grows. They consume as much as 330, 000 calories, almost a ton of greenery every day. To find that much food, herds⁵ roam great distances. Even if they had the brain capacity to care for their young, there just isn’t enough vegetation to let them stay by the nest. 

 

How much of your resources do you put into reproduction, to producing the next generation? And it’s always a trade-off. If you put in a lot of parental⁶ care, then you don’t have the resources to make lots and lots of babies. Or you can go the other way, make tons and tons of babies, but you won’t have the resources left to take very good care of them.

 

Taking care of offspring requires not only brain power but also well-developed senses. Sauroposeidon has neither. Its eyes are separated, located on each side of its head, so it has no ability to judge depth. Its small brain has only rudimentary centers of sight and smell.

1 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》

2 gulp   

vt.吞咽，大口地吸（气）；vi.哽住；n.吞咽

参考例句：

• She took down the tablets in one gulp.她把那些药片一口吞了下去。
• Don't gulp your food,chew it before you swallow it.吃东西不要狼吞虎咽，要嚼碎了再咽下去。

3 voracious   

adj.狼吞虎咽的，贪婪的

参考例句：

• She's a voracious reader of all kinds of love stories.什么样的爱情故事她都百看不厌。
• Joseph Smith was a voracious book collector.约瑟夫·史密斯是个如饥似渴的藏书家。

4 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

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。

6 parental   

adj.父母的；父的；母的

参考例句：

• He encourages parental involvement in the running of school.他鼓励学生家长参与学校的管理。
• Children always revolt against parental disciplines.孩子们总是反抗父母的管束。