英语听力：2013-06-05 完美捕食 Perfect Predators —15

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。

 

Probably stay aloft for a week. Probably it could have gone for 25, 26,000 miles in a single trip. 

 

Quetzalcoatlus is one of the most unusual and terrifying carnivores to inhabit the earth. But unlike predators² such as T-Rex and Deinonychus, this flying meat eater isn’t searching for the big kill. It scours³ the earth from above, tracking the small, the young, the defenseless dinosaur⁴ hatchlings. 

 

Keeping this predator¹ airborne at altitudes as high as 10,000 feet requires a 12-meter wingspan, an accurate guidance system, and near-perfect eyesight.

 

What we see is an enlarged eyeball, an enlarged eye socket⁵, and the processing centers of the brain, the optic lobes⁶ were also very much expanded. 

 

Its 10-centimeter retina is packed with over a billion light receptors and registers as much as four times the detail of the human eye. A Quetzalcoatlus can also see a spectrum⁷ of light invisible to humans, ultraviolet. 

 

The urine of their prey⁸ absorbs U.V. rays and then reflects them back. This creates a light trail leading straight to their quarry⁹. 

 

These animals had very highly developed gaze stabilization¹⁰ mechanisms¹¹, allowing to keep their target fixed¹² and in focus, within the cross hairs, if you will, as they were moving through space. 

 

The secret to gaze stabilization is hidden in the inner ear. Three interconnected tubes form what are called semicircular canals. Fluid fills each canal, and small hairs detect the tiniest movement. As a Quetzalcoatlus’ head moves during flight, signals are sent directly to the eye muscles. The eyeballs adjust, keeping an image fixed and perfectly¹³ in focus. From 300 meters in the air, a Quetzalcoatlus can pick out a T-Rex nest and even count the...

分享到：