英語(yǔ)聽力：恐龍之戰(zhàn)之極限生存—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 milometer’s thick. Even its limbs are far less dense than the bones of many mammals.

　　To look at these big sauropods like Sauroposeidon, they're growing to 20, 30, 40, 50 tons, and they're doing it in a space of just two or three decades.

　　Sauropods grow in spurts, depending on their age, the season, and the availability of food. Scientists know this because their growth is recorded as rings, like rings in a tree trunk.

　　For the first few years of a Sauroposeidon's life, predators are at every turn. One of the most common, Deinonychus is also one of the most deadly.

　　Cunning, definitely cunning. Big brain. Smart.

　　It's the sort of creature that seems very adapt for doing a lot of damage in a short amount of time.

　　Nasty. Deinonychus is a very, very nasty animal that, you know, you meet up with one of these, and your chances of being disemboweled are pretty great.

　　For something like Deinonychus, Sauroposeidon will be a great meal.

　　For the herbivore Sauroposeidon, death by Deinonychus is violent and painful. It's a kill not unlike today's hyenas, one of the Serengeti's most effective predators.

　　When hyenas bite through the gut of antelope, it just stops. It's functionally dead.

　　While juveniles fight it out in the woodlands, adult Sauroposeidon are, as always,foraging for food. With their tiny brains, they live in a world of oblivion, seemingly unaware of the fate of their offspring.