英语听力：2013-04-12 恐龙之战之极限生存 Extreme Survivors—11

I mean, these guys were, frankly dumb as a fence post. Sauroposeidon does almost everything by instinct, including rearing or more accurately not rearing its children. It may seem cruel to just dig a hole and leave your eggs and wander on, but its a

英语听力：2013-04-28 恐龙之战之极限生存 Extreme Survivors—18

Tyrannosaurus Rex, though, lives in an entirely different world. A male devours a Triceratops carcass. Those powerful jaws smash into the meat of the animal. Those gigantic teeth pierce down through flesh. These well-rooted teeth are there to break i

英语听力：2013-04-26 恐龙之战之极限生存 Extreme Survivors—17

It's a digestive process more like those of carnivores. And Sauroposeidon has another trick for growing to mammoth proportions--hollow bones. Its backbone, neck, and ribs have walls just a few milometers thick. Even its limbs are far less dense than

英语听力：2013-04-24 恐龙之战之极限生存 Extreme Survivors—16

Even if the animail managed to survive, the wounds generated from the bite, the prey dinosaur would get weaker and sicker, and the predator could then hunt it down and kill it. Bitten by a T-Rex, and youre downfall, be it now or later. And once you a

英语听力：2013-04-21 恐龙之战之极限生存 Extreme Survivors—15

But with both parents out searching for food, the nest is left unguarded and exposed. Triceratops may be a plant eater, but with a defenseless baby T. Rex around, it'll make an exception. Quetzalcoatlus is the largest flying carnivore in Earth's hist

英语听力：2013-04-19 恐龙之战之极限生存 Extreme Survivors—14

To eviscerate prey, Deinonychus uses both its hands and feet. These were animal that had weapons everywhere you go. Its ridiculous minor weaponry for animal like that size. Its clear its name of all for every reason to be able to dish a lot of damage

英语听力：2013-04-17 恐龙之战之极限生存 Extreme Survivors—13

Sauroposeidon probably had a brain about the size of a kittens, because it was not, unfortunately, a very smart animal. It didnt have to be. It was a food-processing plant. Sauroposeidons five senses are little more than a life-support system for the

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 predators, hatching time is a veritable feast. Even so, the strategy works. Carnivores gulp down virtually every hatchling, but a few do make it, not even the most voracious f

英语听力：2013-04-10 恐龙之战之极限生存 Extreme Survivors—10

One could imagine that the conflict between Tyrannosaurs and Triceratops may have been one of the greatest combats that nature has ever had. And this well-protected herbivore is everywhere. In fact in the Late Cretaceous, Triceratops outnumbered Tyra

英语听力：2013-04-07 恐龙之战之极限生存 Extreme Survivors—9

And there is something else unusual about a T-Rexs nose. The nostrils are a huge 25 centimeters apart, which means T-Rex can smell in stereo. It can triangulate an odor and pinpoint its exact source. T-Rex could walk into a crowded auditorium and in

英语听力：2013-04-05 恐龙之战之极限生存 Extreme Survivors—8

T-Rex is impressive and it's powerful, but compare to Ankylosaurus, it is relatively lightly built. Protective plates made of bone and cartilage covered this lumbering creature from head to tail. Light, but extremely strong, the hide of Ankylosaurus

英语听力：2013-04-03 恐龙之战之极限生存 Extreme Survivors—7

Male lions defend their cubs against rivals who see their offspring as future competition for food and mates. So its likely that an intelligent predator like T-Rex would do the same. Compared to prehistoric plant eaters, its cerebrum, the part of the

英语听力：2013-03-31 恐龙之战之极限生存 Extreme Survivors—6

When you start off coming out of the egg and youre less than, say, 2 feet long and you are in a world full of predators that are loving to crunch on you, then you need to get big fairly quickly. The future seems bleak for this dinosaur. With its life

英语听力：2013-03-29 恐龙之战之极限生存 Extreme Survivors—5

There probably werent many animals of Cretaceous that would dare to try to grab a baby Tyrannosaurus Rex. Quetzalcoatlus could probably manage it. If you see a stork on the Nile today eating a baby crocodile, you can imagine in your mind Quetzalcoatl

英语听力：2013-03-27 恐龙之战之极限生存 Extreme Survivors—4

Tyrannosaurus Rex when we think about it, we tend to think of the big adult because thats the skeletons that we see, but we know that they didnt hatch that way. Once those eggs hatched, weve got an animal thats maybe, you know, three feet long, maybe

英语听力：探索发现 2013-03-10 猛玛象进城记 Mammoths to Manhattan—18

This mass roosting takes place soon after the summer nesting season. Its a chance for the birds to molt before they fly south for the winter. As Vauxs swift numbers reach a peak in mid September, they attract attention from the locals. Coopers hawks

英语听力：探索发现 2013-03-08 猛玛象进城记 Mammoths to Manhattan—17

But there is at least one place in Florida where the manatees benefit from humans being around. Clean, hot water released from this power plant turns a man-made inlet into a hot tub. And during winter months when sea temperatures drop below 20 degree

英语听力：探索发现 2013-03-06 猛玛象进城记 Mammoths to Manhattan—16

This disused car park is a near-perfect location for raising chicks, and only a short flight from a plentiful supply of food. Skimmers get their name from their unusual feeding technique--their extended lower bill detects fish just below the water su

英语听力：探索发现 2013-03-03 猛玛象进城记 Mammoths to Manhattan—15

Moose mainly browse on trees and shrubs, but they will also sample something new. They have a soft spot for pumpkins left out after Halloween. As many as 1,000 moose may enter Anchorage in winter, snowfall here is lower than its surrounding hills and

英语听力：探索发现 2013-03-01 猛玛象进城记 Mammoths to Manhattan—14

Although many of these city foxes do get killed by cars, the population as a whole is thriving. Thats because a regular supply of water means a regular supply of prey, including voles and ground squirrels. Playing on the streets at night is dangerous