评论
打印
Listen to part of a lecture in a Biology class.
请听生物课上的部分内容。
Even though it's cold and snow-covered, the Arctic houses many species of animals that manage to survive the harsh conditions there.
即使非常寒冷且被冰雪覆盖，北极还是成为了许多能够忍受当地严峻环境的动物的家园。
These Arctic animals have adapted to the extremely cold temperatures primarily
主要得益于某些能够帮助它们抵抗寒冷的北极气候的身体特性，
because of certain body features that help them to survive in the cold Arctic climate.
这些北极动物都已经适应了北极的严寒气温。
Let's look at a few of them. For one thing, many Arctic animals have developed a protective covering on their feet.
让我们来看看其中一些动物吧。首先，许多北极动物的脚部都形成了一层保护性的覆盖物。
The covering usually consists of fur or feathers which act as a protective layer between the cold and the animals' skin.
这层覆盖物主要由毛发或者羽毛构成，作为严寒与动物皮肤之间的一层保护层。
Since they spend so much of their time on snowy, icy surfaces,
鉴于它们大部分时间都在满是冰雪的表面上，
whether they are standing on the ground or swimming in the water, they can easily lose heat through their feet.
无论它们是站在地上还是游在水里，它们都很容易从脚部流失热量。
This is especially true of Arctic birds.
对北极鸟类来说尤其如此。
A bird like the Arctic Snowy Owl, for example, has feathers on its body the way other birds do.
比如一种叫北极雪鸮的鸟，它身上羽毛的分布方式和其他鸟类的一样。
But unlike most birds, it also has feathers all over its feet.
但是和大部分鸟类不同的是，它在脚部也长满了羽毛。
This shields and protects the feet from the icy ground
这些羽毛能够作为防护层，保护其脚部不与满是冰雪的地面直接接触，
so that very little of the owl's foot actually touches snowy or icy surfaces, which helps its feet to stay warm.
所以雪鸮的脚部几乎不会碰到冰雪表面，这样便能使其脚部保持温暖。
Another physical characteristic that some Arctic animals share is having smaller bodies and smaller, shorter body parts.
一些北极动物共有的另一个身体特征就是：它们都有较小的身躯和较小较短的身体部位。
In other words, their bodies are often more compact than other animals'.
换句话说，它们的身体通常比其他动物更加紧凑。
And the parts of their bodies that stick out or protrude like the legs, ears or tails are smaller and shorter.
而他们那些突出的身体部位比如腿、耳朵或者尾巴都更小更短。
And the result is that there is less body surface exposed to the cold air.
结果就是它们暴露在寒冷空气中的身体表面更少一些。
A great example is the Arctic wolf.
最好的例子就是北极狼。
Unlike the larger grey wolves that live in warmer climates,
不像生活在温暖地带的大灰狼，
Arctic wolves have relatively small, compact bodies that efficiently retain heat.
北极狼的身体相对来说更小，更紧凑，能够有效地保留热量。
They also have smaller ears and shorter legs so that they lose less body heat than animals with larger bodies or longer body parts.
它们的耳朵也更小，腿更短，所以和身材高大或身体部位纤长的动物相较而言，它们流失的热量更少一些。
And in the climate where the temperature is below zero most of the year, that's very important.
而在常年气温都在零下的地区，这一点非常重要。
