托福听力背景知识：动物迁徙及航行/防御行为常见出题套路及听力要素

Biology一词对于大多数的托福考生而言，并不陌生。自然，生物学也是托福听力常见的考试话题之一，无论是对话还是讲座，都与生物学有着千丝万缕的联系。 今天我们就来给大家详细介绍一下听力考试常见话题生物学中的一个高频考点——动物行为学。帮助大家了解与掌握该考点，一起来看看吧。在正式展开本次主体之前，先帮助各位同学梳理一下，在听力考试中，生物学常考的三种相关话题： 1. 具体讲述某一类动物的特性或对该类动物对具体介绍--常见定义式结构 2. 探究某类细菌或菌落bacterium的功能--常见问题解决式结构 3. animal behavior动物行为--结构不限，重在理解文章主旨 而针对第三类，动物行为学，又可以细分为以下几类情况： 1. 求偶 mating ritual behavior； 2. 抚养后代 parenting behavior； 3. 「昆虫」pollinating behavior； 4. 觅食行为foraging behavior； 5. 玩耍行为play behavior； 6. 迁徙及航行 migration and navigation behavior; 7. 防御行为 preventing predators / defense behavior 本次，我们重点选择后两种行为，来做深入展开，带领同学们一同了解，生物学的常见出题套路以及听力要素。

一、动物学托福听力背景知识

As we all know, 人类的行为受环境的影响以及制约，动物也一样。上述这些行为，实际可以被理解为是动物为了生存而适应环境，所作出的一些行为调整。所以，在animal behavior这类话题中，对话也好，讲座也罢，同学们都要记得把握住一个原则，也就是这类文章的重点：某种动物由于面临着某种生存问题从而演变出了某种行为（文章中高频考点包括：动物该行为的具体表现及其优缺点）。 而在听力考试中，常见的生存问题则可以分为： 1. 环境恶劣（drought, volcano eruption, flood, etc) 2. 天敌predators 3. 资源短缺limited resources 现在，我们一起分析为了保证存活，动物们都是如何做的。

二、迁徙及航行行为

定义：Animal navigation is the ability of many animals to find their way accurately without maps or instruments. Birds such as the Arctic tern, insects such as the monarch butterflyand fish such as the salmon regularly migrate thousands of miles to and from their breeding grounds, and many other species navigate effectively over shorter distances. 动物导航是许多动物在没有地图或仪器的情况下准确找到自己的方向的能力。北极燕鸥等鸟类、帝王蝶等昆虫和鲑鱼等鱼类定期往返繁殖地数千英里，许多其他物种在较短距离内有效航行。

1. 水生动物的航行

在昏暗的深水区域，动物们通常都无法通过眼睛来识别方向。因此，他们获得了一种特殊的定位和航行能力——回声定位。

How do marine mammals use sound to navigate? Sound plays an important role in marine mammal navigation. It may be critical when other senses are of limited use. 声音在海洋哺乳动物的航行中起着重要的作用。当其他感官作用有限时，这可能是至关重要的。 Echolocation by odontocetes (toothed whales) has been extensively investigated. They produce a rapid series of clicks and the return echoes provide important information about objects in their vicinity. Deep diving sperm whales produce a series of clicks at the start of their dives. The interval between their clicks is consistent with detecting multiple elements of their environment, including distance to the seafloor or to the surface. 齿鲸（齿鲸）的回声定位已被人们广泛研究。它们发出一系列快速的咔嗒声，回波提供了有关附近物体的重要信息。深海抹香鲸在开始潜水时会发出一连串的咔哒声。它们咔嗒声之间的间隔与探测其环境的多个元素一致，包括到海底或到表面的距离。 相关题目：20151011 L1 海牛如何在水下航行、定位

2. 飞行动物的航行

对于鸟类来说，飞行则大多是为了获取更多的食物资源、躲避天敌、寻找更适宜的栖息地。

Many species of birds migrate thousands of kilometers every year. Migration is driven mostly by weather and the availability of food. 许多鸟类每年迁徙数千公里。迁徙主要是由天气和食物供应引起的。 In the springtime, birds migrate to temperate regions, where food is plentiful and birds may safely create nests. In autumn, birds migrate to warmer latitudes, following their food sources and more comfortable weather patterns. In the Northern Hemisphere, birds generally fly south for the winter. In the Southern Hemisphere, they generally fly north for the winter. 在春天，鸟类迁徙到温带地区，那里食物丰富，鸟类可以安全地筑巢。秋天，鸟类迁徙到更温暖的纬度，遵循它们的食物来源和更舒适的天气模式。在北半球，冬季鸟类通常向南飞行。在南半球，它们通常向北飞行过冬。 Scientists are not entirely sure how birds navigate their flyways. They seem to have an internal global positioning system (GPS) that allows them to follow the same pattern every year. A young bird imprints on the sun and stars to help orient it. Some researchers think a bird may also recognize landmarks. 科学家们并不完全确定鸟类是如何在飞行路线上导航的。他们似乎有一个内部全球定位系统（GPS），允许他们每年遵循相同的模式。一只小鸟在太阳和星星上留下印记来帮助确定方向。一些研究人员认为鸟类也可以识别地标。 Most surprisingly, a bird’s beak helps contribute to its navigational ability. The beak helps birds determine their exact position. Some researchers think a bird can smell its way across a flyway. This “olfactory map” would orient a bird to terrain and topography. The trigeminal nerve, which connects a bird’s beak to its brain, may also help a bird assess its exact location. Researchers think the trigeminal nerve may help birds evaluate the strength of the Earth’s magnetic field, which is stronger at the poles and weaker at the Equator. 最令人惊讶的是，鸟的喙有助于提高其导航能力。喙帮助鸟类确定它们的确切位置。一些研究人员认为鸟可以闻到自己穿过飞行路线的气味。这张“嗅觉地图”将使鸟类适应地形和地形。连接鸟嘴和大脑的三叉神经也可以帮助鸟类评估其确切位置。研究人员认为三叉神经可能有助于鸟类评估地球磁场的强度，地球磁场在两极较强，在赤道较弱。 相关题目：TPO58 L1 鸟类的归巢行为

三、防御行为

在有了充足的食物供给、适宜的栖息地保障后，动物们仍面临一个巨大的威胁——捕猎者（predator）。要想存活下来，动物必须要通过进化，掌握一些自我防御能力，以求自保。托福考试中常见的四类动物防御行为如下：

1. Camouflage

Camouflage is one form that allows the animal to blend in with its environment and to mask its identity. Cryptic coloration is important to the survival of many new-born and young animals, as it is often their main defense against being detected by predators. Some animals blend in so well with their environment that it is very difficult to identify them. For example, some insects and other animals can look like leaves; both in their visual appearance and their behavior. It is important to note that predators also use cryptic coloration to avoid detection by unsuspecting prey. 伪装是一种形式，使得动物融入其环境，并掩盖其身份。隐色对许多新生和幼小动物的生存非常重要，因为它通常是它们抵御捕食者发现的主要防御。有些动物很好地融入了环境，因此很难识别它们。例如，一些昆虫和其他动物可以看起来像树叶；无论是在他们的视觉外观和他们的行为。值得注意的是，捕食者也使用神秘的颜色来避免被毫无戒心的猎物发现。

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变色龙的伪装行为[/caption]

相关题目：TPO17 L4 章鱼是如何进行自我防御的

2. Trickery

Trickery can also be used as a formidable defense. False features that appear to be enormous eyes or appendages can serve to dissuade potential predators. Mimicking an animal that is dangerous to a predator is another effective means of avoiding being eaten. For example, some harmless snakes have bright warning colors that resemble the colors of dangerously venomous snakes. Warning calls can also be used by one animal species to trick another animal species. 欺骗也可以作为一种强大的防御手段。看似巨大的眼睛或附属物的虚假特征可以用来劝阻潜在的捕食者。模仿对捕食者有危险的动物是避免被吃掉的另一种有效方法。例如，一些无害的蛇有明亮的警告颜色，类似于危险毒蛇的颜色。一种动物也可以用叫声警告欺骗另一种动物。

3. Chemical Features

Chemical features can be just as effective at deterring predators. We all know the hazards of scaring a skunk! The chemicals released result in a not so pleasant aroma that an attacker will never forget. The dart frog also uses chemicals (poisons secreted from its skin) to deter attackers. Any animals that eat these small frogs are likely to get very sick or die. 化学特征在阻止捕食者方面同样有效。我们都知道吓唬臭鼬的危险！释放出来的化学物质会产生一种让天敌反感的气味。飞镖蛙还使用化学物质（皮肤分泌的毒素）来阻止攻击者。任何吃这些小青蛙的动物都有可能生病或死亡。

4. Warning Calls

Some animals sound the alarm when danger approaches. For example, oxpeckers (birds that live in mutualistic relationships with grazing animals) will give a loud warning call when predators get too close. African elephants emit a rumbling alarm call when they hear the sound of African bees. Animals can also give distinctive calls to identify the type of threat. For instance, monkeys have one alarm sound for leopards and a different sound for eagles. 一些动物在危险来临时发出警报。例如，当捕食者离得太近时，啄牛鸟（与放牧动物生活在互惠关系中的鸟类）会发出响亮的警告声。非洲象听到非洲蜜蜂的声音时发出隆隆的警报声。动物也能发出独特的叫声来识别威胁的类型。例如，猴子对豹子有一种报警声，而对鹰有一种不同的报警声。

相关题目：20141221 L3 动物如何通过伪装来躲避捕食者

TD福利 & 领取方式

生物类话题一直都是托福听力考试中的常见话题，其中涉及到的考点和知识背景也需要同学们重点记忆，并且提高对相应话题对熟练度和敏锐度。通过上文，各位大概也已经了解了biology的常见话题，但我们依旧需要配合相应的题目，进行练习加强。本次，笔者也为同学们准备了一份生物话题练习资料——《动物的航行及防御行为》这份资料。

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