英语听力：恐龙是怎样炼成的—19

Oh, this is a bit different. There’re dinosaurs here. Now these guys I recognized. (Yes.) So this is your famous Thomas? (Yes.) Can we get up here? (Sure. Absolutely.)

Face to face to the baby T-rex. With three T-rexes of different ages on one platform, it's possible for the first time ever to get an understanding of the entire life cycle of this legend of the dinosaur kingdom.

So having a series of juvenile skeletons like this gives you insights into the way that dinosaurs grew.

Absolutely. The dinosaurs had growth bursts. So this animal is estimated to have died at the age of two.

Right.

And this one here is estimated to have died at the age 13. There is, you know, there is a sizediscrepancy here, but they are also 11 years apart. Yet this animal is only four years older than this one. Yet it’s enormously bigger than this one. What this is telling you is that between 13 and 17, they were able to add about 1,500 pounds, that’s what 750 kilograms a year.

Wow. And when you see that the two skeletons close to each other like that, you really get a kind of physical impression of that.

Although Thomas towers over the younger T-rexes, even he wasn't fully grown. But at about 17 years old, he was already 11 meters long and over three tons in weight.

So this is a juvenile, this enormous skeleton.

Indeed. Indeed. It’s an animal that probably died at the age of 17, so rather young.

So he's still a teenager.

You can tell that he's a juvenile not only based on the histology on the bone tissue for which we have studies of it, but also because there are many bones that would fuse when the animal was a full-grown that have yet not been fused, one of them missed here, the calcaneum and the astragals

are completely unfused and both with the tibia.

And it's not just the phenomenal speed at which they grew that Luis’ shedding light on. The final addition to this platform would be carcass of another dinosaur, the T-rexes' dinner. It will give us an insight into how the three T-rexes may have interacted.