【英语时差8,16】狼到中年（在线收听）

Middle Aged Wolves Picture an elk walking through the forest, looking for some berries to nibble. Then, suddenly, a pack of wolves leaps from the bushes, surrounding the startled animal. The wolves close in. The elk looks for an escape route, but the predators tighten the circle. The elk is a goner, right? Maybe. But it depends partly on the age of the wolves. According to one study, wolves’ hunting skills peak around age three, and then their hunting prowess starts to decline. By the time wolves reach old age, around the age of six, they’re no longer the same hunters they were as youngsters. Why ?Because unlike lions, tigers, and other large predators, the average wolf doesn’t have the bulk or attributes to take down large prey with a single blow. Wolves rely more on athleticism and endurance to bag elk. And like most athletes, wolves’ physical abilities decline with age. Once their skills erode, wolves aren’t much good as hunters. So older wolves are good for elk. The study found that the older the average wolf population in an area, the more elk there are still around. When the wolf population skews younger, more elk bite the dust.