来源：沪江听写酷 2011-12-01 12:05
Now we're entering Kangaroo Country. In all, there are more than 50 different species of kangaroo, and the advantage of zoos like ours is that you see them in their natural habitat. The ones we have all live in the grasslands. On my right, you can see one of the biggest types: the red kangaroo. It travels about 20 miles per hour. It looks like hard work, but hopping actually lets the kangaroo conserve more energy than another animal could when running on four legs. In fact, up to a certain point, the faster a kangaroo goes the more energy it conserves. Rather than taking more hops to increase speed, the kangaroo makes the length of each jump longer. Let's stop here for a minute. Take a look over on your right at this group of kangaroos resting. Can you see that their ears are moving? Hearing may well be the kangaroo's most important sense. Their two large ears can move independently, so sometimes one ear is pointing forward and the other toward the rear. Kangaroos' eyesight is also excellent. They have a wide field of vision and, like most grazing animals, they are especially good at detecting movement. Before we move on, I'd like to point out one more thing: If you look closely, you can see a joey - that's a baby kangaroo - peering out of its mother's pouch. Before long that joey will be out of the pouch for good. The mother will push it out by the time it's eight months old.