>51 Marine Mammals
      Since there is such an abundance of food in the sea, it is understandable that some of the efficient, highly adaptable, warm-blooded mammals that evolved on land should have returned to the sea. Those that did have flourished. Within about 50 million years -- no time at all, geologically speaking -- one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth.
      This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in on these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on the top of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea. There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

      海洋哺乳动物
      既然海洋中有如此丰富的食物，一些原本在陆地生存的高效率的，适应性强的暖血型动
物返回海洋生存是不难理解的。 那些已经返回海洋的哺乳动物种族繁荣。 在大约 5 千万年 间(这在地质学上不过是弹指一挥间)，返回海洋的 4 种浦乳动物之一的鲸已成为体积最庞大 的动物。 而另一种哺乳动物海豹，它的数量恐怕是地球上大型食肉哺乳动物中最大的。 这 似乎表明这些海洋中的"大哥大"们人丁兴旺，一派繁荣景象。但至少在近 150 年以来，事实 并非如此。 同样是暖血动物而且效率更高、适应性更强的捕食者，人类，成为这些哺乳动 物的日益迫近的威胁。 在陆地和海洋，人类都已处在巨大的生物金字塔的最顶端，成为所 有生物的主宰，并给海洋哺乳动物带来巨大的危胁。 原因很简单。 这些哺乳动物不幸成为 人类所需要的一堆游动着的商品，如皮毛、油和肉。 尽管如此，如果它们不象人类一样繁 殖如此缓慢，它们对人类的掠夺也不会如此无能为力。 每年人类从海洋中捕捞约 5 千万吨 的鱼类，但这并未导致任何鱼种的灭绝。但繁殖缓慢的海洋哺乳动物却因为有了一心只想满 足一已私欲的人类而濒临。
>52 Chimpanzee
      The most striking single fact about chimpanzees is the flexibility of their social life, the lack of any rigid form of organization. It represents about as far a departure from the baboon type of organization as one can find among the higher primates, and serves to emphasize the great variety of primate adaptations. Chimpanzees are more human than baboons, or rather they jibe better with the way we like to picture ourselves, as free-wheeling individuals who tend to be unpredictable, do not take readily to any form of regimentation, and are frequently charming.(Charm is relatively rare among baboons.) Two researchers have described what they found during more than eight months spent among chimpanzees in their natural habitat the forest:"We were quite surprised to observe that there is no single distinct social unit in chimpanzee society. Not only is there no 'family' or 'harem' organization; neither is there a 'troop' organization - that is to say, no particular chimpanzees keep permanently together. On the contrary, individuals move about at will, alone or in small groups best described as bands, which sometimes form into large aggregations.
      They leave their associates if they want to, and join up with new ones without conflict. " The general practice is best described as "easy come, easy go", although there are certain group-forming tendencies. As a rule chimpanzees move about in one of four types of band: adult males only; mothers and offspring and occasionally a few other females; adults and adolescents of both sexes, but no mothers with young and representatives of all categories mixed together. The composition of bands may change a number of times during the course of a day as individuals wander off and groups split or combine with other groups. On the other hand, certain individuals prefer one another's company. One of the researchers observed that four males often roamed together over a four-month period, and mothers often associated with their older offsprings.

      黑猩猩
      黑猩猩最突出的一个特征是它们社会生活的灵活性，即缺乏固定的组织形式。 它的这 一特征与狒狒的那种组织形态间的差别，在灵长动物中最为突出。 由此可见灵长类动物中 适应性变化的多样性。 黑猩猩比狒狒更接近人类，或者说它与我们心愿的自我形象更为接 近：自由自在，不落窠臼，不喜欢任何形式的约束并且往往魅力十足(在狒狒中魅力比较罕 见)。 通过在黑猩猩的自然栖息地森林中对它们进行了 8 个月的观察，两名研究人员得出这样结论："我们注意到在黑猩猩的社会中似乎没有任何一种独立的社会基本单位，这一点令 我们很吃惊。 它们不仅没有'家庭'或'妻妾'组织，也没有'团队'组织，也就是说黑猩猩没有固 定地生活在一起。 相反，每只黑猩猩随意流动，或是独自一人，或是作为最好称之为团伙 的一员。 团伙有时会与其它团伙合并成大的聚合体。 它们可以随意离开同伴，并与其它黑 猩猩组成新的团伙而不会产生任何纠纷。"把黑猩猩这一总的特性称之为"来得容易去得快" 是最恰当不过了。 但它们也有一定的群体倾向性。 通常，黑猩猩群的构成有以下 4 种：仅 有成年雄性； 母猩猩及其子女而且偶尔有几只其它的雌性猩猩； 雄性和雌性的成年和未成 年黑猩猩但不包括有子女的雌性黑猩猩； 以及各种类型混杂在一起。 一天之中一个团伙的 组成可能变化好几次，因为有的成员可能离开，而且群体可能会与其它群体合并。 另一方 面，有些黑猩猩有自己喜欢的伙伴。 一名研究人员发现四只雄性黑猩猩在 4 个月中常常共 同游荡，还有母亲们常与她们较年长的子女们在一起。