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  • 海龟

    A hand in a glove points at a nest of turtle eggs in sand.

    What are these?
    ::这些是什么?

    This picture might look like a bunch of ping-pong balls, but actually it's a picture of turtle eggs . Notice the soft, leathery shell that is typical of eggs.
    ::这张照片可能看起来像一堆乒乓球,但其实是海龟蛋的图片。注意软皮壳,这是典型的鸡蛋。

    Turtles
    ::海龟

    Turtles are reptiles in the order Testudines . If you have seen turtles before, what is the most noticeable thing about them? Their shells. Most turtle bodies are covered by a special shell developed from their ribs. Their shells can be bony or cartilaginous , made from a more flexible supportive tissue . About 300 species are alive today, and some are highly endangered. Like other reptiles, turtles cannot regulate their body temperature, except with behavioral means, such as burrowing underground. Turtles have adapted to environments and environments. Turtles that live primarily on land are generally called tortoises.
    ::龟类是按动物顺序排列的爬虫类。如果你以前见过海龟,那么它们最引人注目的是什么?它们的贝壳。大多数海龟的身体被从它们的肋骨中培养出来的特别壳壳所覆盖。它们的贝壳可以是坚硬的,也可以是圆形的,用较灵活的辅助组织制成。今天约有300种物种存活,有些物种濒临高度灭绝。与其他爬虫类一样,海龟无法调节体温,除非有行为手段,如在地下挖洞。海龟已经适应了环境与环境。主要生活在陆地上的海龟通常被称为龟。

    Turtles are broken down into two groups, based on how they bring their neck back into their shell:
    ::海龟被分成两组,

    1. Cryptodira, which can draw their neck inside and under their spine.
      ::它可以把他们的脖子拉到脊椎里和脊椎下
    2. Pleurodira, which fold their necks to one side.
      ::Pleurodira, 将他们的脖子折成一面。

    Characteristics of Turtles
    ::海龟的特征

    Although many turtles spend large amounts of their lives underwater, they can also spend much of their lives on dry land and breathe air. Turtles cannot breathe in water, but can hold their breath for long periods of time. Turtles must surface at regular intervals to refill their lungs .
    ::尽管许多海龟在水下度过大量生命,但他们也可以在旱地和呼吸空气中度过大部分生命。 海龟不能在水中呼吸,但可以长时间屏气。 海龟必须定期浮出水面以重新填充肺部。

    The position of a turtle's can give a clue to their natural habitat . Most turtles that spend most of their lives on land have their eyes looking down at objects in front of them. Some aquatic turtles, such as snapping turtles and soft-shelled turtles, have eyes closer to the top of the head. These species of turtles can hide from predators in shallow water, where they lie entirely submerged in water except for their eyes and nostrils.
    ::海龟的位置可以提供自然栖息地的线索。大部分在陆地上度过大部分生命的海龟都俯视眼前的物体。有些水生海龟,如海龟和软壳龟,其眼睛靠近头部顶部。这些海龟的物种可以躲在浅水中的捕食者身上,除了眼睛和鼻孔之外,它们完全沉浸在水中。

    Sea turtles ( Figure  ) have glands near their eyes that produce salty tears, which remove excess salt taken in from the water they drink.
    ::海龟(图)眼旁有腺,产生咸眼泪,从饮水中取出过多的盐。

    A sea turtle showcasing eye placement, shell shape, and flippers.
    A species of sea turtle, showing placement of eyes, shell shape, and flippers.

    Turtles have exceptional night due to the unusually large number of cells that sense light in their eyes. This allows them to be active at any time of the day. Turtles also have color vision.
    ::海龟的夜色不同寻常,因为有异常多的细胞在眼睛中感知光线。这使得海龟可以在白天的任何时候活动。海龟也有颜色视觉。

    Turtles don’t lay eggs underwater. Turtles lay slightly soft and leathery eggs, like other reptiles. The eggs of the largest species are spherical, while the eggs of the rest are longer in shape. After internal fertilization , a female is ready to lay her eggs, she places a large numbers of eggs in holes dug into mud or sand. They are then covered and left to grow and develop by themselves. When the turtles hatch, they squirm their way to the surface and head toward the water. They need to get to the water as fast as possible before they are fed upon by animals such as seabirds, crabs, and raccoons.
    ::海龟不会在水下产卵。海龟像其他爬行动物一样产下柔软的和有皮的卵。 最大物种的蛋是球状的,而其他物种的蛋的形状则更长。 在体内施肥后,雌性动物准备产卵,她将大量的卵放入挖进泥土或沙子的洞里。然后,它们被覆盖并独自生长和发育。 当海龟孵化时,它们会冲向表面,向水头。 它们需要尽快到达水中才能被海鸟、螃蟹和浣熊等动物喂食。

    How do Turtles Eat?
    ::海龟怎么吃?

    Turtles may appear slow and harmless when they are out of the water, but in the water is another story. Turtles can be either herbivores or carnivores , with most sea turtles carnivorous . Turtles have a rigid beak and use their jaws to cut and chew food. Instead of teeth, the upper and lower jaws of the turtle are covered by horny ridges. Carnivorous, or animal-eating turtles usually have knife-sharp ridges for slicing through their prey . But as the turtle is not a very fast animal, and it cannot quickly turn its head to snap at prey, it does have some limitations. Sea turtles typically feed on jellyfish , and other soft-bodied organisms . Some species of sea turtle with stronger jaws eat shellfish, while other species, such as the green sea turtle, do not eat any meat at all. Herbivorous turtles have serrated ridges that help them cut through tough plants.
    ::海龟在从水中出来时可能看起来很慢,无害,但在水中则是另一个故事。海龟可以是草食动物或食肉动物,大多数海龟都是食肉动物。海龟有硬嘴,用下巴割断和咀嚼食物。没有牙齿,海龟的上下两下两下两下的海龟被角性脊覆盖。食肉动物或食动物的海龟通常有刀尖的脊,通过猎物切除。但是,由于海龟不是非常快的动物,它不能很快地将头转向猎物,它确实有一些限制。海龟通常食用水母和其他软骨生物。有些海龟的下巴吃贝类,而其他物种,如绿海龟则不吃任何肉类。海龟的海龟有经腐蚀的海脊,可以帮助他们通过坚硬的植物切割。

    How Big Are Turtles?
    ::大海龟怎样?

    The largest turtle is the great leatherback sea turtle ( Figure  ), which can have a shell length of seven feet and can weigh more than 2,000 pounds. The only surviving giant tortoises are on the Seychelles and Galápagos Islands and can grow to over four feet in length and weigh about 670 pounds ( Figure  ). The smallest turtle is the speckled padloper tortoise of South Africa, measuring no more than three inches in length, and weighing about five ounces. The largest ever turtle was the know extinct Archelon genus , a Late Cretaceous sea turtle known to have been up to 15 ft long, and 16 ft wide from flipper to flipper. The closest living relative of this genus is the leatherback sea turtle.
    ::最大的海龟是大棱皮海龟(Figure ) , 其壳长7英尺,重量超过2 000磅。唯一幸存的巨龟在塞舌尔和加拉帕戈斯群岛上,长超过4英尺,体积约为670磅(Figure ) 。最小的海龟是南非的斑点板形海龟,长度不超过3英寸,体积约为5盎司。最大的海龟是已知的已灭绝的海龟Archelon genus,一个已知长达15英尺的过时的白鲸海龟,以及从翻接到翻接的16英尺宽的海龟。这个海龟最接近的活生生的海龟是皮龟。

    It was the giant Galápagos tortoises that Charles Darwin studied during his voyage on the Beagle, providing significant evidence that he used to support his theory of evolution. 
    ::查尔斯·达尔文在航行于比格尔号时研究的 巨型巨型加拉帕戈斯海龟 提供了他用来支持进化理论的重要证据

    Great leatherback sea turtle, notable for its large size and unique shell structure.
    The leatherback turtle can reach up to seven feet in length and weigh over 2,000 pounds.
    A giant tortoise resting on grass with greenery in the background.
    A giant tortoise can grow to over feet ft in length and weigh about 670 lb. These animals can easily live over 100 years, spending their days grazing on grass, leaves, and cactus, basking in the sun, and napping nearly 16 hours each day.

    Summary
    ::摘要

    • Most turtle bodies are covered by a special bony or cartilaginous shell developed from their ribs.
      ::多数海龟尸体都由从肋骨中制成的一团特别的圆壳或圆柱壳所覆盖。
    • Turtles cannot breathe in water, although many turtles spend large amounts of their lives underwater.
      ::海龟不能呼吸在水中,尽管许多海龟在水下度过大量生命。

    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

    • A Moment of Science at (1:25)
      ::科学时刻(1:25)

     

     

    1. How does cloacal respiration work?
      ::阴道呼吸怎么起作用?
    2. Why is this sort of respiration vital for the turtles?
      ::为什么这种呼吸对海龟至关重要?

    Explore More II
    ::探索更多情况二

    • The Leatherback Turtles and Ocean Currents at (4:06)
      ::皮革背龟和洋流(4:06)

     

     

    1. How many populations of leatherback turtles ( Dermochelys coriacea ) are there in the Pacific Ocean?
      ::太平洋有多少只棱皮龟(多温海龟)?
    2. Why do scientists feel that beaches like Playa Grande are important to the survival of this species?
      ::为什么科学家觉得像Playa Grande这样的海滩 对这个物种的生存很重要?
    3. How could natural selection explain why leatherback turtles favor beaches like Playa Grande?
      ::自然选择如何解释 皮革龟为何偏爱普莱亚格兰德这样的海滩?

    Review
    ::回顾

    1. How are turtles divided into two groups?
      ::海龟如何分为两组?
    2. How and what do turtles eat?
      ::海龟吃什么?
    3. Do turtles breath underwater? Explain.
      ::海龟在水下呼吸吗?