英语听力：2013-05-12 完美捕食 Perfect Predators —5

 Hearing, smell and sight are all well refined. 

 

We can look at the sense of vision and see the attributes of a predator¹. 

 

T-Rex’s eyes are 40 centimetres apart providing exceptional binocular vision, the ability to perceive depth.

 

An eye is essentially² just a photon-catching device. Tyrannosaurus would have had an extremely large retina over which they could collect those photons. 

 

Collecting more photons gives the brain more visual information to interpret, more detail about its surroundings. And those eyes are crucial for an alfa hunter for another reason.

 

A Tyrannosaur’s eyes were quite high up, and therefore they always had a very tall perspective on the world. It could see great distances. For them, the horizon was very, very far away. 

 

A T-Rex can distinguish fine visual detail as far away as six kilometers, eyesight far superior to that of humans. Its hearing is also a significant advantage for a hunter. 

 

What we see in the inner ear of T-Rex is a hearing organ that’s long and suggests that hearing was very important to T-Rex. 

 

It’s called the cochlea. It’s a hollow, cone-shaped tube filled with liquid. This tube vibrates in response to sound waves. Thousands of tiny hair-like cells detect this movement, then send electrical signals to the brain. The cochlea in a Tyrannosaurus Rex is 2.5 centimentres long, so it can pick up a wide range of frequencies. 

 

It was able to actually hear very low frequency sounds. And so something even off in the distance was gonna be within its perceptive³ world. 

 

It doesn’t want to hear the peeping and piping of little birds around there because they’re not gonna be something it eats. But if its hearing the infrasound grunts of a Triceratops, that’s what it wants to hear, because that…

1 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

2 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

3 perceptive   

adj.知觉的，有洞察力的，感知的

参考例句：

• This is a very perceptive assessment of the situation.这是一个对该情况的极富洞察力的评价。
• He is very perceptive and nothing can be hidden from him.他耳聪目明，什么事都很难瞒住他。