英语听力：2013-07-17 《恐龙的战争》3 顽强防御—14

搜索关注在线英语听力室公众号：tingroom，领取免费英语资料大礼包。

 

What was a surprise is the higher centers of their brain are very large and suggest that something very different is going on in Parasaurolophus and its kin¹ than in most other of these plant-eating dinosaurs³.

 

But how does an advanced auditory cortex help a Parasaurolophus defend itself against monster carnivores? First of all, its acute hearing can detect an approaching predator⁴ from kilometers away. Then most importantly, it can react, deploying⁵ an unusual weapon, a distinctive⁶ sound that originates deep inside a strangely shaped head crest⁷.

 

The crest contains the animal’s nasal cavity—a tube that loops around twice, creating a chamber⁸ two and a half meters long. Calls, vibrations⁹ originating in the voice box travel along these tubes. Like the chambers¹⁰ of a trombone, those tubes amplify¹¹ and lower that sound. The result—an extremely low-frequency hum, even deeper than a foghorn¹².

 

Each species has its own distinct shape. Each species would have its own distinct sound.

 

The arrangement of the chambers inside each animal is unique. And the sound they create is like a fingerprint¹³. These calls are Parasaurolophus’ primary form of defense¹⁴. They are communicative, social beings that live in herds¹⁵. Parasaurolophus have learned there’s safety in numbers.

 

An isolated¹⁶ Parasaurolophus would be a dinosaur² in trouble. It’s gonna have to look out for predators¹⁷ on its own. And therefore, a lone individual might do its call to say, “I’m alone”, and wait to hear for…

分享到：