英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—19

There is no mistaking yet. She is ready to mate. Finally, the lover/ unites a bit briefly. After two months, the breeding season is over. It is time for the long track back to their southern feeding grounds, but the females carrying the next generati

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—18

Here and now, cub and cub, pound for pound. The bodies of the falling litter the battle field. The females approach to the victorious males willingly, and with a discerning eye. They gravitate to the i/ storm, knowing that only the fittest gladiators

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—17

Even fearsome wasps high in treetops, are no match for the implacable ants. They watch helplessly as their own larvae are stripped from their honeycomb cribs. Now, the porters take up their burdens, they carry the movable feast back to the unquenchab

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—16

Tonight the newly winged young would join the feeding frenzy.They are now fully fledged members of the colony,ready to investigate the bounty of this land,and dark in the dusk with breathtaking numbers once again. Morning in Costa Rica ,and the army

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—20

After months on awkward shores, they are going home. The young albatross fledglings left behind days ago, rave their engines on their necks, testing the force for the wings and hauling wings that will power them around the world. It is time to fly or

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—13

And the raptor executes his cool mercy.In the rolling surf, rockhoppers pop home with their garlics full. They take turns shuttling to the sea daily , having tibets of quilt to feed their growing chicks. Once ashore, the rockhoppers trade their long

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—14

At the top, red eyed, yellow browed and full of spunk, they celebrate their ascent and reunion, and are quickly assorted by their ravenous chicks. Now, the earlier, the bigger the adults. More food is the chorus ringing out up and down the shores and

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—15

Some freshwater crocs try to snap them out of the air, others wait for fatal mistakes. But many more make it through. And after many hours on the wing, they find their new paradise, fresh, succulent eucalyptus at the highest bloom. At dawn, they sele

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—12

Unable to leave his harem to feed its seed, hes losing 50 pounds of blabber a day. All ready the albatross checks a hatching in staggering numbers downy and demanding with unending patience. The new mother waits for her mate to return for his far ori

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—11

Almost magically, they form a temporary nest of their own bodies. The larvae and food are taken into the nursery at its centre. Tomorrow they will do the whole thing again, marching for two to three weeks to reach fresh hunting grounds, where they ca

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—10

The nursery lies at the heart of a twitching, thriving structure, built almost entirely of the aunts of themselves. Long legs stuck together with tussle cores. They are the scaffolding, bricks, and mortar of the nests. But theyve been in one place fo

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—9

By November, the blinding equatorial sun has turned their southern water holes into sucking mud, a trap for unwary youngsters and so they must move north toward permanent water. Their pace quickens with the male's need to reach their ancient battle g

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—8

In the war-racked country of Sudan, lies Boma National Park, the largest intact savanna in East Africa. Mile upon mile of what looks like pristine wilderness unfolds. But much of this is an empty paradise. During the Sudan's decades of ruinous civil

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—7

But they can't migrate to greener pastures until the last of the youngsters has been winged. So mother has become stingy and edgy. Readying for the migration ahead, she tongues oily secretions over every bit of her flight equipment. A bat's wings are

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—6

Parenting on the move is all about sacrifice. And in the forests of northeastern Australia, another great journey spurred by parental dedication is about to begin. On translucent tawny wings, a little red flying fox flaps homeward after a night of in

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—5

Blood runs freely from slashed noses and necks. They even fight dirty, going for the eyes. The loser's breeding chances for now are ground into the sand. But this beachmaster's triumph is just the beginning of his troubles. Ahead lie dozens of fights

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—4

An egg tumbled from the nest is fair game for Johnny rook. He'll soon have his own clamoring brood to look after. On another stretch of beach, the shoreline quakes with desperate battles to dominate. The stakes are unimaginably high. Only a privilege

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—3

From tip to tip, its wings stand eight feet. This superb blighter can soar almost e* 24 hours a day. Waiting in this bustling, the troublous of hundreds of thousands of birds, her mate shores up the nest from last year's breeding. And after seven lon

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—2

And for Johnny rook, the wait is over. Because some of the world's greatest wanderers are heading his way. They've been traveling the globe for months, even years. Only one thing can bring their wanderings to a halt, none of them can give birth at se

英语听力：自然百科 大迁徙之繁衍生息 Need to Breed—1

They are driven to move, to move and to multiply. Possessed by the /insatiable need to breed, they will journey to brutal African battle fields, and grow on South Atlantic shores. For the sake of their young, they will blacken the skies, and terroriz