动态英文托福阅读真题第286篇HowHerdingCanProvideSafety（答案文章最后）
How Herding an Provide Safety
In open grasslands there is no place for a large animal to hide. Thus a watchful grazing animal will e the slight movement that betrays the prence of a predator long before it is clo enough to launch an attack. It sounds as though the hunters (predators) stand no chance at all. Unfortunately for the grazers, life is not so simple, however. grazing animal must lower its head and look at the ground to feed. Its attention may be occupied for only a few conds before it rais its head and resumes its watch while chewing the food it took, but hunters are patient and skillful and are concentrating intenly. Tho few conds provide time enough to advance a few steps and then freeze, body flattened against the ground. It may take hours, but eventually the repeated small advances will put the hunter within range—clo enough to outrun its prey—and the long time the hunt has taken will have been worthwhile, becau the resulting feast will be highly nutritious.
learly the grazers are at a disadvantage, becau while they eat they are vulnerable to atta
ck. The hunters also have a weakness, however, and it is one that allows the grazers to survive. Hunters can attack only one prey animal at a time. This applies even to the predators that hunt as a team, such as lioness, wolves, and hunting dogs. Their hunt involves running down or ambushing an individual. Teamwork allows them to hunt animals much bigger and stronger than themlves and to hunt more successfully, but it does not allow them to attack more than one individual at a time.
广州塔附近美食
he grazers exploit this weakness by making it as difficult as they can for the predators to choo an individual as a target. They do not graze alone, scattered widely across the landscape, but together, as a herd. The approaching hunter es not a solitary animal, but a crowd of animals, all of them moving, so they are constantly crossing and recrossing each other’s paths. No sooner does the hunter choo an individual than another animal has crosd in front of it and the target has disappeared into the herd. From the hunter’s point of view this is highly confusing behavior—as, indeed, it is meant to be.
咽喉炎的症状有哪些
安全生产法培训There is another advantage to the grazers. herd is much more alert than a solitary animal. n animal has to relax its guard while it is taking food, but in a herd there are at any time some animals with their heads down, biting, and others, with their heads up, watching. What is more, tho with their heads up are looking in different directions so that together they are alert to any movement anywhere on the landscape around them. There is no way for a hunter to approach a herd unobrved. When a member of the herd spots trouble, it starts to move away. Other members of the herd move with it and the entire herd starts to move. If the trouble is rious and clo, the herd will run. The individual raising the alarm is simply protecting itlf, but in doing so it is warming all of the others.
像乔丹一样打球
Herding is highly successful, provided members of the herd stay together in a tight bunch. The hunter moves with the herd, watching for an individual to wander away from the others. When that happens, it tries to move between that individual and the rest of the herd, preventing it from rejoining. Once it has done that the hunter has a good chance of making a kill. If the herd starts to run, a solitary hunter may abandon the cha, but a pac
k of wolves or hunting dogs will regard the running herd of animals as an opportunity and t off in pursuit. s the herd runs, one or two old or sick animals, or young animals that become parated from their mothers, may fall behind.
s soon as the hunter or hunters ize their prey, they lo interest in all other grazers since then they, too, must concentrate on eating, at which point the herd stops running, tho who were left behind rejoin the group, and they all resume grazing.
银行数据分析
蛇年祝福1
►In open grasslands there is no place for a large animal to hide. Thus a watchful grazing animal will e the slight movement that betrays the prence of a predator long before it is clo enough to launch an attack. It sounds as though the hunters (predators) stand no chance at all. Unfortunately for the grazers, life is not so simple, however. grazing animal must lower its head and look at the ground to feed. Its attention may be occupied for only a few conds before it rais its head and resumes its watch while chewing the food it took, but hunters are patient and skillful and are concentrating intenly. Tho few con
ds provide time enough to advance a few steps and then freeze, body flattened against the ground. It may take hours, but eventually the repeated small advances will put the hunter within range—clo enough to outrun its prey—and the long time the hunt has taken will have been worthwhile, becau the resulting feast will be highly nutritious.
