英语听力：自然百科 探索世界奥秘之Life in the Freezer (冰雪童话) Unit04（在线收听）

Humpback whales. During the brief summer they gorge themselves on krill. When the krill swarms are near the surface, the humpbacks collect them by lunging. They simply open their cavernous mouths and scoop it up. Often the whales cooperate, working together as fishing boats do. When the krill is more dispersed, the whales have to dive deeper. After a while, lines of bubbles appear on the surface. The bubbles gradually form a pattern that spirals inwards, then suddenly in its center, the whales appear.

Time and again, the pair dive. When they reach the bottom of the dive, they start releasing bubbles and continue to do so as they swim upwards, spiraling around one another. These curtains of bubbles rise through the water, creating a ring on the surface. Underwater, the curtains drive the krill into the center of the spiral and the humpbacks then surge up through the middle, jaws agape.

The humpbacks that visit Antarctica only feed during the brief southern summer, building their reserves for the winter that will be spent in less productive northern waters. And so, for hour after hour, throughout the long Antarctic day, these 40-ton creatures perform a splendidly synchronized and very productive underwater ballet.

New Words & Phrases

Humpback: (n.) A humpback whale. 座头鲸

lunge: (v.) A sudden forward movement or plunge. 冲，扑

scoop: (v.) To gather or collect swiftly and unceremoniously; grab 掏

agape: (a.) Wide open. 大张着的