Their natural predators have been killed off.

他们的天敌已被灭绝。

With no natural predators on the island, the herd increased rapidly.

由于岛上没有天然食肉动物，牧群的数量迅速增加。

I mean, doesn't it attract more predators?

我的意思是，它不会吸引更多的捕食者吗？

In the ocean，we fished for top predators such as cod.

在海洋中，我们捕捞像鳕鱼这样的顶级食肉动物。

How do predators affect populations of the prey animals?

捕食者如何影响猎物的数量？

Of course, hungry predators sometimes ignore the warning.

当然，饥饿的捕食者有时会忽视这种警告。

The major concern of the snowshoe hare in the winter is predators.

雪靴野兔冬天最大的担忧是捕食者。

Over time animals have developed many ways to stay away from 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。

Two factors appear to be generating the cycle: food plants and predators.

产生这种循环的因素有两个：食用植物和食肉动物。

With a decline in starfish predators, the starfish population can increase.

随着海星捕食者的减少，海星的数量会增加。

All that movement makes it hard for predators to see individuals in a large group.

所有这些运动使得捕食者很难在一个大群体中看到个体。

The octopus is prey to many species, including humans, so how does it escape its predators?

章鱼是许多物种的猎物，包括人类，那么它如何逃脱捕食者的猎杀呢？

The behaviors that the birds engage in to distract predators are called distraction displays.

鸟类做来分散捕食者注意力的行为被称为注意力分散展示。

The problem is that other smugglers are predators, who abandon, kidnap or kill their charges.

问题是有些人贩是掠夺者，他们抛弃、绑架或者杀害被他们绑架的人。

Greenstone suggested that predators may select food items according to their nutrient contents.

格林斯通认为，捕食者可能会根据食物的营养成分来选择食物。

As one of the most brutal predators, killer whales may not fit the image of a cultured creature.

作为最残忍的掠食者之一，虎鲸可能不符合文明动物的形象。

Presumably, the more often it wanders from home, the more it's likely to be exposed to predators.

推测来讲，它离家越频繁，就越有可能暴露在捕食者面前。

Predators are an essential factor in maintaining communities that are rich and diverse in species.

捕食者是维持群落物种丰富多样的一个重要因素。

I read that they often hide from predators by squirting out a cloud of ink, or something like that.

我读到过，它们为了躲避捕食者，经常喷出一团墨水，或者类似的东西。

The bats are able to avoid other predators, and locate prey—typically insects that fly around at night.

蝙蝠能避开其他捕食者，找到猎物——通常是夜间飞行的昆虫。

Wild pigs attracted golden eagles from the mainland, and those flying predators crashed the fox population.

岛上的野猪引来了大陆的金雕，这些飞行的捕食者们导致岛屿灰狐的数量大幅下降。

However, a different explanation is necessary in cases where the vigilant behavior is not directed at predators.

然而，在警觉行为不针对捕食者的情况下，则需要不同的解释。

Another potential cost of this activity is greater exposure to predators since play is attention-getting behavior.

这种行为的另一个潜在代价是更大程度地暴露在捕食者面前，因为玩耍是获得注意力的行为。

Population cycles are characteristic of small mammals, and they sometimes appear to be brought about by predators.

数量的周期循环是小型哺乳动物的特征，它们有时似乎是由捕食者造成的。

They're willing to make more trips to haul back less wood, which carries a greater risk of being exposed to predators.

它们宁愿多走几次，每次只带回较少的木料，这就增加了在捕食者面前暴露的风险。

Low prey population levels then provide inadequate food for the predators, causing the predator population to decrease.

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。

Why does their behavior indicate more of a concern with how much energy they expend than with being exposed to predators?

为什么它们的行为表明它们更关心的是消耗多少能量而不是担心暴露在捕食者面前呢？

Given that predators can make it costly to beg for food, what benefit do begging nestlings derive from their communications?

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？

For instance, islands often have not been colonized by large predators or are too small to hold feasible predator populations.

例如，岛屿通常没有大型食肉动物的殖民地，或者太小而无法容纳可行的食肉动物种群。

Removing waterfowl-nest predators could affect songbird nesting success through subsequent increases in small-mammal populations.

清除水禽巢捕食者可能会通过随后小哺乳动物数量的增加影响鸣禽筑巢的成功。