You can never know how well Tyrannosaurs could count, but I imagine Mom would be a little bit perplexed when suddenly she was down to five instead of six and there was no sign of where it had gone.
你永远无法想象霸王龙会数数，但我可以想象当母恐龙突然发现六个孩子变成五个而另一个不知道哪里去了时的困惑。
For a baby Tyrannosaurus Rex, danger lurks everywhere. But at least he has a fighting chance.
对于小霸王龙来说，危险无处不在。但他至少有战斗的机会。
For infant Sauroposeidon, it's another story altogether. They are born defenseless. And alone.
对于波塞东龙幼崽，又是另一种情况了。它们生来毫无保护。孤苦伶仃。
If you want to have intensive parental care, you can only take care of a limited number of offspring.
如果你想得到父母的精心呵护，你只能照顾有限数量的后代。
If you want to have lots of offspring, you have to have little or no parental care. Sauropods took that route.
如果你选择拥有很多后代，父母的呵护只能少之又少了。波塞东龙选择了那条路。
From birth, Sauroposeidon is in a race for survival.
从出生开始，波塞东龙便开始了生存的竞赛。
For every 3,000 hatchlings, only 1 will make it to adulthood.
每三千只孵化的幼兽，只有一只可以长大。
And to become that one survivor, it must fend for itself for years.
为了成为那唯一的幸存者，相当长的时间内，它必须自食其力。
For this future giant, there's just one rule-grow or die.
对于这些未来的庞然大物，规则只有一条——成长或死亡。
When we look at Sauropod tracksites, where we have tracks of hundreds of individuals all together, there's a curious thing.
当我们观察数百只波塞东龙集体迁徙的路线时，令我们好奇的事发生了。
These big groups of sauropods always include only the adults and the animals down to about 1/3 of full size.
这些巨型的蜥脚类动物群中只有成年恐龙和三分之一的青壮年恐龙。
Growing up alone means growing up in constant danger.
独自成长意味着要面对无数危险。
So, think about a juvenile Sauroposeidon that's the size of a pony or a horse.
所以一只波塞东龙幼龙的体型类似马驹或马那么大。
It has no sharp teeth, no plates, no spikes, no horns, no armor. It's not even very fast.
它没有尖利的牙齿，盾骨和尖刺，没有犄角和甲壳。它的速度甚至都比较缓慢。
And so, what would happen to those juvenile Sauroposeidons if they were faced by a pack of Deinonychus? Well, they would die.
那么，如果波塞东龙幼龙遭遇到了一群恐爪龙会怎样呢？它们必死无疑。
Sauroposeidon navigates a world of hungry predators.
波塞东龙来到了一群饥饿的掠食者中。
When you start off coming out of the egg and you're less than, say, 2 feet long and you're in a world full of predators that are loving to crunch on you, then you need to get big fairly quickly.
当幼龙从卵中孵化出来时大概也就不到两英尺长，而且处在一个充满掠食者的世界中，它们酷爱猎杀幼龙，所以幼龙就必须尽快长大。
The future seems bleak for this dinosaur.
这只恐龙将要厄运临头了。
With his life on the constant threat, how will it survive?
如此的艰险世界中它将如何生存。
