In the Cretaceous Period, plant eaters faced vicious killers.
在白垩纪，食草动物们不得不面对凶残的杀手。
And none has a worse reputation than Tyrannosaurus Rex, possibly the largest land predator that has ever lived.
这其中没有比霸王龙更臭名昭著的了，它可能是迄今为止最大的陆生食肉动物。
T. Rex is sort of the quintessential monster. A dinosaur with an attitude.
某种程度上说霸王龙是最完美的怪兽。充满敌意的恐龙。
A Tyrannosaurus Rex can grow to five 5.5 meters tall and 12 meters long, with jaws designed to tear meat to shreds.
霸王龙可以长到5.5米高，12米长，它们的下颚天生就是用来撕碎血肉的。
It's reputation for violence and terror is unmatched.
它那狂暴和恐怖的名声无人能及。
But a infant T. Rex comes into the world better protected than most.
但是霸王龙的幼崽在出生后会受到比多数幼崽更好的保护。
If you say "Tyrannosaurus Rex", I think of gentleness.
如果你提起"霸王龙"，我会想到温柔。
I think of superb motherhood and a struggle to raise one's chicks.
我会想到伟大的母性和养育幼崽的艰辛。
The dreaded Tyrannosaurus Rex, it turns out, is one of the most nurturing of all dinosaur parents.
令人恐惧的霸王龙却是恐龙家庭中最擅长育雏的家长。
It means taking care of the eggs, sticking around the nest, defending the nest, and keeping track of its progress.
这意味着对蛋的细心照料，在巢穴附近徘徊守护巢穴，时刻关注蛋的动向。
Tyrannosaurus rex means "tyrant lizard king."
霸王龙的意思是"蜥蜴暴君"。
And this beast rules a world where physical traits more than intelligence determine winners and losers.
它统治着这个身体特征比智力因素更能决定成王败寇的世界。
But T. Rex has both-- superb biomechanics and, by dinosaur standards, a sharp intellect.
但霸王龙两者兼得，完美的生理结构，还有相对恐龙标准来说的敏锐思维。
It was the result of many, many millions of years of specialization for large body size, for focus on prey, for sensory apparatus, and for the ability to dispatch a large herbivore.
这是数百万年特化的结果，才有了它的庞大身躯，执着捕食，感觉器官，还有杀死大型食草动物的能力。
With things like Tyrannosaurus Rex, you have bigger brains, you have the option for more complex behaviors, especially when it comes to parental care.
对于霸王龙，它们拥有更大的大脑，可以选择更加复杂的行为，尤其是亲代育雏方面。
For three months, an adult delicately guards the nest to ensure the survival of their youngsters and the continuation of their genes.
在三个月时间里，成年霸王龙都会悉心保护巢穴以确保幼崽的存活和基因的延续。
You've got to have somebody that's very, very attentive when these little things hatch.
当这些小家伙孵化时必须确保时时刻刻有人关注。
Inside the egg, the embryo breathes in oxygen and exhales carbon dioxide.
在蛋的内部胚胎吸入氧气，呼出二氧化碳。
The CO2 dissolves in fluid, making carbonic acid, which will slowly weakens the shell.
二氧化碳溶解于胚胎组织液中，形成碳酸会慢慢腐蚀蛋壳。
Before long, a meter long T. Rex chick breaks free.
没过多久，一米长的霸王龙幼崽破壳而出了。
You can imagine T. Rex helping its young out of the shell, even with those big, giant jaws.
你可以想象霸王龙帮助幼崽破壳而出的场景，即使用它那巨大的下颚。
The hatchling is tiny compared to its gigantic parents.
刚孵出的幼崽与庞大的父母相比是如此瘦小。
And it's immediately under threat.
它们很快就被威胁萦绕左右。
