英語聽力：恐龍之戰(zhàn)之極限生存—3

Its reputation for violence and terror is unmatched, but an infant T-Rex comes into the world better protected than most.

If you say Tyrannosaurus Rex, I think of gentleness. I think of superb motherhood and a struggle to raise one’s chicks.

The dreaded Tyrannosaurus Rex, it turns out, is one of the most nurturing of all dinosaur parents.

It means taking care of the eggs, sticking around the nest, defending the nest and keeping track of its progress.

Tyrannosaurus Rex means tyrant lizard king and this beast rules a world where physical traits more than intelligence determine winners and losers. But T-Rex has both superb biomechanics and by dinosaur standards, a sharp intellect.

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.

With things like Tyrannosaur Rex, you have bigger brains; you have the option for a more complex behaviors, especially when it comes to parental care.

For three month, an adult delicately guards the nest to ensure the survival of their youngsters and a continuation of their genes.

You’ve got to have somebody that’s very, very attentive when these little things hatch.

Inside the egg, the embryo breathes in oxygen and exhales carbon-dioxide. The CO2 dissolves in fluid, making carbonic acid which will slowly weaken the shell. Before long, a meter-long T-Rex chick breaks free.

You can imagine a T-Rex helping its young out of the shell, even with those big giant jaws.

The hatchling is tiny compared to its gigantic parents and it’s immediately under threat.