英语听力：自然百科 Wolf Hunting Tactics 合作至上的狼群

We are here in Yellowstone National Park to follow some grey wolves and observe the deadlybrilliance of the pack. They’ve learned to cooperate, hunting their prey with manyacting as one pack.

This mother grizzly knows how to protect its cub and itself. Stand your ground. Don’t beintimidated. Don’t let the grey wolves run you down. Grizzly mum stands up to the grey wolves. And eventually, they lose interest.

Stand up, hold your ground. Wolves know that large prey can be dangerous if they fight back. What the wolves want is to get their prey on the run. Like, for example this herd of elk. Now the wolves can fan out over the herd, waiting for an old or sick or just unlucky elk to make a wrong move. The alpha male leads the hunt. He bides his time, directing his troops. And eventually, one elk stumbles.

The hungry wolves quickly surround their faltering victim. They swarm in for the kill, and then, the meal. Wolves are a vital part of a healthy Yellowstone echo-system. They filter out sick and weak animals in the herds and help scavengers survive but providing leftovers from their hunts. This coyote however is not a scavenger but also a competitor, who's beeninterfering with the kills of the pack.

So once again, the wolves use cooperation to guard their turf and drive out the intruder.