章节大纲

  • 常规

    全部折叠 展开全部

  • Crocodilia 鳄

    A crocodile resting on sandy ground near a rock, showcasing its V-shaped snout.

    Crocodile or Alligator?
    ::鳄鱼还是鳄鱼?

    This picture is a crocodile, identified by it's V-shaped snout. Alligators have more of a U-shaped snout. Although crocodiles and alligators have a few differences, they are very much alike and belong to the same order , Crocodilia.
    ::这张照片是鳄鱼,由V形的鼻子来识别。鳄鱼的U形鼻子更多。虽然鳄鱼和鳄鱼有一些不同,但它们非常相似,属于同一顺序,克罗科迪利亚(Crocodilia)。

    Alligators and Crocodiles
    ::鳄鱼和鳄鱼

    Crocodilia, containing both alligators and crocodiles, is an order of large . Reptiles belonging to Crocodilia are the closest living relatives of . Reptiles and birds are the only known living descendants of the dinosaurs . Some would day that alligators and crocodiles actually look like small dinosaurs. Dinosaurs that evolved wings are the ancestors of birds.
    ::鳄鱼既含有鳄鱼,也含有鳄鱼,是大型的顺序。属于鳄鱼的爬虫是最近的活亲属。爬虫类和鸟类是恐龙的唯一已知活后代。有的鳄鱼和鳄鱼实际上长得像小恐龙。进化翅膀的恐龙是鸟类的祖先。

    The basic crocodilian body plan ( Figure ) is a very successful one and has changed little over time. Modern species actually look very similar to their Cretaceous ancestors of 84 million years ago. All species of crocodilians have similar body structures, including an elongated snout, powerful jaws, muscular tail, large protective scales, streamlined body, and and nostrils that are positioned on top of the head.
    ::基本鳄鱼肉体计划(图)非常成功,而且随着时间的推移变化不大。 现代物种实际上看起来与8400万年前的白鲸祖先非常相似。 所有鳄鱼都有着类似的身体结构,包括长鼻子、强下巴、肌肉尾巴、大防护尺度、精简体形和鼻孔,它们都放在头顶上。

    Nile crocodiles resting together by the water, showcasing their distinctive features and body plan.

    Nile crocodiles display the basic crocodilian body plan.
    ::尼罗河鳄鱼展示了基本鳄鱼体计划。

    Characteristics of Crocodiles
    ::鳄鱼的特征

    Crocodilians have a flexible, semi-erect posture. They can walk either in a low, sprawled “belly walk,” or hold their legs more directly underneath them to perform the “high walk.” Most other reptiles can only walk in a sprawled position.
    ::鳄鱼有灵活、半过敏的姿势。 它们可以走低、无孔不入的“大胆行走 ” , 或者更直接地把腿放在下面进行“高度行走 ” 。 大部分其他爬行动物只能走无孔不入的姿势。

    All crocodilians have, like humans, teeth set in bony sockets. But unlike mammals , they replace their teeth throughout life. Crocodiles and gharials (large crocodilians with longer jaws) have salivary glands on their tongue, which are used to remove salt from their bodies. This helps with life in a saltwater environment. Crocodilians are often seen lying with their mouths open, a behavior called gaping . One of its functions is probably to cool them down.
    ::像人类一样,所有鳄鱼都有牙套。但与哺乳动物不同,它们在整个生命中取代牙齿。鳄鱼和长嘴鳄鱼(大鳄鱼和长下巴)的舌头上有盐碱性腺,用来去除体内的盐。这有助于咸水环境中的生活。人们经常看到鳄鱼张着嘴躺在床上,一种叫做隔膜的行为。它的一个功能可能是冷却它们。

    The crocodilian is highly adapted to their lifestyle. Crocodilians are known to swallow stones, known as gastroliths , which help digest their prey . The crocodilian stomach is divided into two chambers. The first is powerful and muscular. The other stomach is the most acidic digestive system of any animal . It can digest mostly everything from their prey, including bones , feathers , and horns!
    ::鳄鱼高度适应其生活方式。 鳄鱼以吞咽石块为名, 称为胃骨, 有助于消化猎物。 鳄鱼胃分为两个室。 第一个是强大和肌肉。 另一个是动物中最酸性的消化系统。 它能吸收猎物中的所有东西, 包括骨头、羽毛和角!

    All crocodilians are carnivores . They feed on live animals such as birds, small mammals and . Crocodilians use several methods of attack when pursuing live prey. One approach is that of the ambush. The crocodilian lies motionless beneath the water's surface with only their nostrils above the water line. This keeps them concealed while they watch for prey that approaches the water's edge. The crocodilian then lunges out of the water, taking their prey by surprise and dragging it from the shoreline into deep water where the prey is killed.
    ::鳄鱼是食肉动物,它们食用鸟类、小哺乳动物和小哺乳动物等活动物。鳄鱼在捕食活猎物时使用几种攻击方法。一种方法是伏击。在水面下面的鳄鱼躺着不动,只有鼻孔在水线上方。这使他们躲藏起来,看着接近水边的猎物。鳄鱼然后从水中跳出来,突然地捕食猎物,然后把猎物拖进猎物被杀死的深水中。

    The sex of developing crocodilians is determined by the temperature of the eggs during incubation , when eggs are kept warm before they hatch. This means that the sex of crocodilians is not determined genetically. If the eggs are kept at a cold or a hot temperature, then their offspring may be all male or all female. To get both male and female offspring, the temperature must be kept within a narrow range.
    ::孕育过程中的卵的温度决定了孕育过程中蛋的性别,当卵在孵化前保持温暖时,这表示克隆人的性别不会在基因上确定。如果卵处于寒冷或热温中,那么它们的后代可能是男性或全部女性。要让男女生都生,温度必须保持在狭小范围内。

    Female crocodilians care for the young after they hatch, providing them with protection until they grow large enough to defend themselves. In many species of crocodilians, the female carries her tiny offspring in her mouth.
    ::孕育后,雌性鳄梨种植者会照顾幼童,并为他们提供保护,直到它们长大到足以自卫的地步。 在很多种类的鳄梨种植者中,雌性将幼子放在她的嘴里。

    Evolving More Complex Structures
    ::不断演变的更复杂结构

    Like all reptiles, crocodilians have a relatively small brain , but the crocodilian brain is more advanced than those of other reptiles. Because of their habitat , the eyes, ears, and nostrils are all located on the same "face" in a line one after the other.
    ::和所有爬行动物一样,鳄鱼的大脑相对较小,但鳄鱼的大脑比其他爬行动物的大脑更先进。 由于它们的栖息地、眼睛、耳朵和鼻孔,它们都位于同一个“脸”上,一个接一个的线条上。

    The crocodiles have advanced sensory organs . They see well during the day and may even have color , and they also have excellent night vision. A third transparent eyelid, the nictitating membrane , protects their eyes underwater. The eardrums are located behind the eyes and are covered by a movable flap of skin. This flap closes, along with the nostrils and eyes, when they dive. This prevents water from entering their external head openings. Their jaws are covered with sensory pits , which hold bundles of nerve fibers that respond to the slightest disturbance in surface water. Crocodiles can detect vibrations and small pressure changes in water. This makes it possible for them to sense prey and danger even in total darkness, and becomes very useful when the animal is submerged in the water.
    ::鳄鱼有先进的感官器官,白天看好,甚至可能有颜色,夜间视力也很好。第三只透明的眼皮,动静的膜,保护着它们的眼睛。耳膜位于眼睛后面,被皮肤的可移动片覆盖。这个扇形,连同鼻孔和眼睛,在它们下潜时都闭着。这阻止了水进入它们的外部头部孔。它们的下巴被感官坑覆盖,里面有一捆神经纤维,可以应对地表水的轻微扰动。鳄鱼可以探测到振动和水中的微小压力变化。即使在完全黑暗中,它们也能感觉到猎物和危险,当动物被浸入水中时也变得非常有用。

    Like mammals and birds, and unlike other reptiles, crocodiles have a four-chambered heart. But, unlike mammals, with and without oxygen can be mixed.
    ::鳄鱼和哺乳动物和鸟类一样,与其他爬行动物不同,鳄鱼有四组心脏。 但是,与哺乳动物不同,有氧和没有氧是混合的。

    Summary
    ::摘要

    • Crocodilians swallow stones, known as gastroliths, which help digest their prey.
      ::鳄鱼吞咽石块, 被称为胃石, 帮助消化它们的猎物。
    • The sex of developing crocodilians is determined by the temperature of the eggs during incubation.
      ::生长氯丙二烯的性别取决于孵化期间卵的温度。
    • The crocodiles have advanced sensory organs, including keen eyesight, eardrums, and sensory pits that detect disturbances in the water.
      ::鳄鱼有先进的感官器官,包括敏锐的视力、耳膜和感官坑,可探测到水中的扰动。

    Explore More
    ::探索更多

    Use the resources below to answer the questions that follow.
    ::利用以下资源回答以下问题。

    Explore More I
    ::探索更多

    • American Alligator at
      ::美国美洲鳄鳄
    1. Where do American alligators live?
      ::美国鳄鱼住在哪里?
    2. What do alligators eat?
      ::鳄鱼吃什么?
    3. What conditions have led to the recovery of the American alligator?
      ::是什么条件导致美国鳄鱼的恢复?

    Explore More II
    ::探索更多情况二

    • Bubble-Blowing Saltwater Crocodiles at (1:53)
      :伤心1:53)时的鳄鱼
    1. In what kind of courting displays do saltwater crocodiles ( Crocodylus porosus ) engage?
      ::盐水鳄鱼(Crocodylus porosus)在什么种类的求偶展示中扮演什么角色?
    2. Do saltwater crocodiles have internal or external fertilization?
      ::咸水鳄鱼有体内或外部肥化吗?

    Explore More III
    ::探索更多三

    • Baby Siamese Crocodiles at (4:05)
      ::4:05时,育婴暹粒鳄鱼
    1. What kind of maternal care do crocodile mothers show their young? When does this care begin?
      ::鳄鱼妈妈给她们年轻的孩子展示什么样的产妇护理?这种护理什么时候开始?
    2. What do baby crocodiles do as soon as they hatch?
      ::幼鳄孵化后会怎么做?
    3. Why is it important for mother crocodiles to guard their nests?
      ::为什么母鳄鱼必须守住巢穴?

    Review
    ::回顾

    1. Name four features that all crocodilians share.
      ::列出四个特征,所有鳄鱼都分享这些特征。
    2. How is the sex of alligators and crocodiles determined?
      ::鳄鱼和鳄鱼的性别是如何确定的?
    3. Describe digestion in crocodilians.
      ::描述鳄鱼的消化。
    4. Describe the special sensory organs of crocodiles.
      ::描述鳄鱼的特殊感官器官