01

十

乌龟(turtle) vs. 乌龟语言学(tortoise linguistics)

Few things in the animal kingdom are more confusing than the difference between turtles and tortoises, for linguistic (rather than anatomical) reasons. Terrestrial (non-swimming) species should technically be referred to as tortoises, but residents of North America are just as likely to use the word "turtle" across the board. Further complicating matters, in Great Britain "turtle" refers exclusively to 海洋物种，而且决不允许陆栖龟。为了避免误解，大多数科学家和自然资源保护主义者将海龟、乌龟和水龟统称为“龟类”或“龟鳖”。专门研究这些爬行动物的博物学家和生物学家被称为“龟鳖学家”

02

十

他们分为两大家族

The vast majority of the 350 or so species of turtles and tortoises are "cryptodires," meaning these reptiles retract their heads straight back into their shells when threatened. The rest are "pleurodires," or side-necked turtles, which fold their necks to one side when retracting their heads. There are other, more subtle anatomical differences between these two Testudine suborders. For example, the shells of cryptodires are composed of 12 bony plates, while pleurodires have 13, and also have narrower vertebrae in their necks. Pleurodire turtles are restricted to the 南半球，包括非洲、南美洲和澳大利亚。隐翅虫在全世界都有分布，是最常见的海龟和乌龟物种。

03

十

贝壳牢固地附着在它们的身体上

You can forget all those cartoons you saw as a kid where a turtle jumps naked out of its shell, then dives back in when threatened. The fact is that the shell, or carapace, is securely attached to its body. The inner layer of the shell is connected to the rest of the turtle's skeleton by various ribs and vertebrae. The shells of most turtles and tortoises are composed of "scutes," or hard layers of keratin. The same protein as in human fingernails. The exceptions are soft-shelled turtles and leatherbacks, the carapaces of which are covered with thick skin. Why did turtles and tortoises evolve shells in the first place? Clearly, shells developed as a means of defense against predators. Even a starving shark would think twice about breaking its teeth on the carapace of a 加拉帕戈斯乌龟

04

十

它们有鸟一样的喙，没有牙齿

You might think turtles and birds are as different as any two animals can be, but in fact, these two vertebrate families share an important common trait: they're equipped with beaks, and they completely lack teeth. The beaks of meat-eating turtles are sharp and ridged. They can do serious damage to the hand of an unwary human, while the beaks of herbivorous turtles and tortoises have serrated edges ideal for cutting fibrous plants. Compared to other reptiles, the 咬海龟和乌龟的数量相对较弱。尽管如此，鳄鱼咬龟仍能以每平方英寸超过300磅的力量咬住猎物，与成年男性差不多。然而，让我们从正确的角度来看问题：咸水鳄鱼的咬合力超过每平方英寸4000磅！

05

十

有些人活了100多年

As a rule, slow-moving reptiles with cold-blooded metabolisms have longer life spans than comparably-sized mammals or 鸟. 即使是一只相对较小的箱龟也能活30或40年，而加拉帕戈斯乌龟也能轻易达到200岁的寿命。如果它能成功地存活到成年期（大多数海龟宝宝永远都没有机会，因为它们孵化后会立即被捕食者吞食），海龟将因为它的壳而不受大多数捕食者的伤害。有迹象表明，这些爬行动物的dna经历了更频繁的修复，它们的干细胞更容易再生。老年学家对海龟和乌龟进行了大量的研究，他们希望分离出能够帮助延长人类寿命的“神奇蛋白质”，这一点也不足为奇。

06

十

大多数人的听力不太好

Because their shells provide such a high degree of protection, turtles and tortoises haven't evolved the advanced auditory capabilities of, for example, herd animals like wildebeest and antelopes. Most Testudines, while on land, can only hear sounds above 60 decibels. For perspective, a human whisper registers at 20 decibels. This figure is much better in the water, where sound conducts differently. The vision of turtles isn't much to brag about, either, but it gets the job done, allowing 食肉的用来追踪猎物的龟鳖。此外，有些海龟特别适合在夜间观看。总的来说，testudines的总体智力水平较低，尽管一些物种可以被教去驾驭简单的迷宫，而另一些物种则具有长期记忆。

07

十

他们在沙子里下蛋

Depending on species, turtles and tortoises lay anywhere from 20 to 200 eggs at a time. One outlier is the eastern box tortoise, which lays only three to eight eggs at once. The female digs a hole in a patch of sand and soil deposits her clutch of soft, leathery eggs, and then promptly ambles away. What happens next is the kind of thing producers tend to leave out of TV nature documentaries: nearby carnivores raid the turtle nests and devour most of the eggs before they've had a chance to hatch. For example, 乌鸦浣熊吃掉大约90%的海龟产卵。一旦卵孵化出来，几率也不会太大，因为没有硬壳保护的未成熟海龟会像有鳞的开胃菜一样被吃掉。为了繁殖该物种，每窝只需要一到两个幼体存活；其他人最终成为食物链的一部分。

08

十

他们的最终祖先生活在二叠纪时期

Turtles have a deep 进化史这可以追溯到中生代之前的几百万年，更广为人知的是恐龙时代。最早确定的testudine祖先是一种一英尺长的蜥蜴，叫做eunotosaurus，它生活在2.6亿年前的非洲沼泽中。它的背部弯曲着宽大、细长的肋骨，这是后来海龟和乌龟壳的早期版本。testudine进化中的其他重要环节包括晚三叠世的pappochelys和早侏罗世的Ordontochelys，这是一种拥有全套牙齿的软壳海龟。在随后的数千万年中，地球上居住着一系列真正可怕的史前海龟，其中包括archelon和protostega，每一只都重达两吨。

09

十

他们不是理想的宠物

Turtles and tortoises may seem like the ideal "training pets" for kids (or for adults who don't have a lot of energy), but there are some very strong arguments against their adoption. First, given their unusually long lifespans, Testudines can be a long-term commitment. Second, turtles need very specialized (and sometimes very expensive) care, especially in regard to their cages and food and water supplies. Third, turtles are 沙门氏菌携带者，严重的病例会使你住院，甚至危及你的生命。你不一定要接触海龟才能感染沙门氏菌，因为这些细菌可以在你家的表面滋生。保护组织的普遍观点是海龟和乌龟属于野外，而不是孩子的卧室。

10

十

苏联曾经把两只乌龟射入太空

It sounds like a science-fiction TV series, but Zond 5 was actually a spacecraft 由苏联发射1968年，它载着一堆苍蝇、蠕虫、植物和两只可能非常迷失方向的乌龟。zond 5绕月球一周后返回地球，在那里发现这些乌龟体重减轻了10%，但在其他方面都很健康和活跃。海龟凯旋归来后发生了什么还不得而知，考虑到它们的品种寿命很长，它们很可能今天还活着。人们喜欢想象它们被伽马射线突变，被炸成怪物大小，然后在海参崴边缘的后苏联研究设施中度过晚年。