英語聽力：冰河綠洲—5

But the glyptodont wasn't a reptile. So what was it? There is a relative of the glyptodont that’s still alive today. It's the armadillo and it's a mammal, the only mammal with this kind of armor in the whole of North America. It may give us some idea of how an ice age glyptodont might have looked when alive.

Armadillos have poor eyesight and rely mostly on their sense of smell. Much of their time is spent nose to the ground in search of food.

Like the glyptodont, they are covered in a layer of bony scutes. But the armadillo's body armor is surprisingly thin and flexible and doesn't slow its owner down. So what about the glyptodont?

The glyptodont's scute casing was up to 5 centimetres thick and fused into a solid shell. The shell alone is extremely heavy. And the entire animal probably weighed as much as a small car. It had extremely sturdy legs and five toes on each foot to spread its massive weight. The heavy tail probably acted as a counterbalance. So the glyptodont wasn't built for speed, but inside all this body armor, you'd imagine it was well protected. But one fossil skull tells a different story. It suggests the glyptodont's defences weren't impenetrable.