捕食者如何影响猎物的数量？
捕食性动物是一种猎食其他动物的动物。
我的意思是，它不会吸引更多的捕食者吗？
随着海星捕食者的减少，海星的数量会增加。
With a decline in starfish predators, the starfish population can increase.
它的作用是在章鱼逃跑时分散捕食者的注意力。
It serves to distract a predator while the octopus makes its escape.
捕食者是维持群落物种丰富多样的一个重要因素。
Predators are an essential factor in maintaining communities that are rich and diverse in species.
推测来讲，它离家越频繁，就越有可能暴露在捕食者面前。
Presumably, the more often it wanders from home, the more it's likely to be exposed to predators.
随着时间的推移，动物们已经发展出许多远离捕食者的方法。
Over time animals have developed many ways to stay away from predators.
蝙蝠能避开其他捕食者，找到猎物——通常是夜间飞行的昆虫。
The bats are able to avoid other predators, and locate prey—typically insects that fly around at night.
较少的猎物数量为捕食者提供了不足的食物，导致捕食者数量减少。
Low prey population levels then provide inadequate food for the predators, causing the predator population to decrease.
蝙蝠们遇到了一个技术上的难题：如何在没有光线的条件下认路和捕食。
Bats have an engineering problem: how to find their way and find their prey in the absence of light.
例如，海星捕食各种双壳类软体动物，防止这些双壳类动物独占海底的栖息地。
For example, sea stars prey on a variety of bivalve mollusks and prevent these bivalves from monopolizing habitats on the sea floor.
这是雪鞋兔的一个巨大的优势，因为相比之下，它的捕食者的脚通常会陷进雪里。
This is a huge advantage for the snowshoe hare since, by contrast, the feet of its predators usually sink right down into the snow.
由于引入了非本地的捕食者和病原体，已经有许多本土物种灭绝的记录，证据确凿。
There have been numerous well-documented extinctions of indigenous species caused by the introduction of non-indigenous predators and pathogens.
这种意想不到的颜色表现会吓到捕食者或使其迷惑，并为潜在的猎物提供逃跑的机会。
This unexpected display of color startles or confuses the predator and provides the would-be prey with an opportunity to escape.
因此，从多样性的角度来看，将一种主要捕食者从一个群落中彻底消灭通常是一个错误。
Therefore, from the stand point of diversity, it is usually a mistake to eliminate a major predator from a community.
正如预测的那样，在光线下孵化的小鸟主要用右眼寻找食物，而用另一只眼睛观察是否有捕食者。
As predicted, the birds incubated in the light looked for food mainly with their right eye, while using the other to check out the predator.
现在，让我们来看一个自然捕食者的具体例子，它会对珊瑚礁造成很大的伤害——那就是刺冠海星。
Now let's focus on a specific example of a natural predator that can cause a lot of damage to coral reefs—the Crown of Thorns, or CoT starfish.
特别是，龙虾幼虫需要更短的时间才能长到不再容易受到幼鳕鱼捕食的大小，幼鳕鱼是它们生存的主要威胁。
In particular, lobster larvae take less time to reach the size at which they are no longer vulnerable to predation by young cod, the chief threat to their survival.
当狮子及其他捕食性动物觉得自己正被注视着时，它们就不大可能会继续袭击，这种想法就是基于这一原理。
This idea is based on the principle that lions and other predators are far less likely to attack when they feel they are being watched.
既然捕食者可以让雏鸟为食物付出巨大代价，那么乞食的雏鸟们到底可以从这种交流方式中得到什么益处呢？
Given that predators can make it costly to beg for food, what benefit do begging nestlings derive from their communications?
十年前，这个岛的生态系统处于混乱状态，野猪吸引了来自大陆的金雕，而那些飞行的捕食者又使狐狸的数量锐减。
A decade ago, this island's ecosystem was in chaos. Wild pigs attracted golden eagles from the mainland, and those flying predators crashed the fox population.
玩耍可以让一只小动物探索环境并在相对安全的环境中练习技能，因为周围的成年动物通常不期望幼崽应对威胁或捕食者。
Play allows a young animal to explore its environment and practice skill in comparative safety since the surrounding adults generally do not expect the young to deal with threats or predators.
海豹在水下更长时间地遨游，在这段时间里，它似乎是在探索遥远的路线，或是在躲避捕食者，这确实能唤起我们在实验室里看到的潜水反应。
The seal's longer excursions underwater, during which it appears to be either exploring distant routes or evading a predator, do evoke the diving response seen in the laboratory.
比如说，像小鹿或者山羊这种被捕食的种群，它们的代表动作就是突然快速逃跑的动作和突然转弯；相反的，猫科动物之类的捕食种群会练习潜行追踪、猛扑和撕咬等动作。
Prey species, like young deer or goats, for example, typically play by performing sudden flight movements and turns, whereas predator species, such as cats, practice stalking, pouncing, and biting.
在这种情况下，捕食者和被捕食者可能会在一段时间内继续这种循环模式。
In this situation, the predator and prey population may continue in this cyclical pattern for some time.
狮子捕食全凭偷袭。
猫不捕食海豹。
当某个捕食者靠近时，它们会尽力吸引这个捕食者的注意。
When a predator approaches, they do their best to attract the attention of that predator.
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